CHARTWELL RE HOLDINGS CORP
8-K, 1999-12-22
ACCIDENT & HEALTH INSURANCE
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                       SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 20549
                                 ---------------

                                    FORM 8-K

                                 CURRENT REPORT
                     PURSUANT TO SECTION 13 OR 15(d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934



Date of Report (Date of earliest event reported)        December 19, 1999
                                                --------------------------------

                        Chartwell Re Holdings Corporation
- --------------------------------------------------------------------------------
             (Exact Name of Registrant as Specified in its Charter)



Delaware                               0-28188                 06-1438493
- --------------------------------------------------------------------------------
State or Other Jurisdiction          (Commission             (IRS Employer
of Incorporation)                     File Number)           Identification No.)



Four Stamford Plaza,  P. O. Box 120043, Stamford, CT               06912-0043
- -------------------------------------------------------       -----------------
         (Address of Principal Executive Offices)                  (Zip Code)



Registrant's telephone number, including area code   (203) 705-2500
                                                   -----------------------------


          (Former Name or Former Address, if Changed Since Last Report)




<PAGE>



Item 5. - Other Events

         Trenwick Group Inc., a Delaware  corporation  ("Trenwick"),  the parent
company  of  Chartwell  Re  Holdings  Corporation,  entered  into  a  definitive
Agreement,  Scheme of  Arrangement,  Plan of Merger and Plan of  Reorganization,
dated as of  December  19,  1999 (the  "Business  Combination  Agreement")  with
LaSalle Re Holdings Limited, a Bermuda company ("LaSalle"),  LaSalle Re Limited,
a Bermuda  company  ("LaSalle  Re"),  Trenwick Group  (Delaware)  Inc. and Gowin
Holdings International Limited,  pursuant to which the stockholders of Trenwick,
the common  stockholders of LaSalle and the minority  shareholders of LaSalle Re
will each  exchange  their shares on a  one-for-one  basis for shares in a newly
formed Bermuda  company (the "Business  Combination").  See the full text of the
Business Combination  Agreement which is filed herewith as Exhibit 2.1 and which
is incorporated by reference herein.

         In connection  with the Business  Combination  Agreement,  Trenwick and
LaSalle  have  granted to each other  options to  purchase  up to 19.9% of their
outstanding  shares  pursuant  to  Stock  Option  Agreements,  each  dated as of
December 19, 1999.  See the full text of the Stock Option  Agreements  which are
filed herewith as Exhibits 99.1 and 99.2 and which are incorporated by reference
herein.

         Certain  shareholders  of LaSalle  and  LaSalle Re have  agreed to vote
their  shareholdings  in  favor  of  the  Business  Combination  pursuant  to  a
Shareholders Agreement,  dated as of December 19, 1999. See the full text of the
Shareholders  Agreement  which is filed  herewith  as Exhibit  99.3 and which is
incorporated by reference herein.

         On December 19, 1999, Trenwick and LaSalle issued a joint press release
announcing the Business Combination, which is filed herewith as Exhibit 99.4 and
which is incorporated by reference herein.

Item 7. Financial Statements and Exhibits

(c)      Exhibits

2.1      Agreement,   Scheme  of  Arrangement,   Plan  of  Merger  and  Plan  of
         Reorganization,  dated as of December 19, 1999, by and among LaSalle Re
         Holdings  Limited,  LaSalle Re Limited,  Trenwick Group Inc.,  Trenwick
         Group (Delaware) Inc. and Gowin Holdings International Limited.

99.1     Stock Option Agreement, dated as of December 19, 1999, between Trenwick
         Group Inc. and LaSalle Re Holdings  Limited  (option granted to LaSalle
         Re Holdings Limited).

99.2     Stock Option Agreement, dated as of December 19, 1999, between Trenwick
         Group Inc. and LaSalle Re Holdings Limited (option granted to Trenwick
         Group Inc.).

99.3     Shareholders  Agreement,  dated as of December 19,  1999,  by and among
         Trenwick Group Inc.,  Combined  Insurance Company of America,  Virginia
         Surety Company,  Inc., Aon Risk Consultants (Bermuda) Ltd., Continental
         Casualty Company and CNA (Bermuda) Services Limited.

99.4     Press release of Trenwick Group Inc. and LaSalle Re Holdings Limited
         issued December 19, 1999.



                                    SIGNATURE

         Pursuant to the  Requirements  of the Securities  Exchange Act of 1934,
the  registrant  has duly  caused  this report to be signed on its behalf by the
undersigned hereunto duly authorized.

                                            CHARTWELL RE HOLDINGS CORPORATION


                                            By:   /s/ James F. Billett, Jr.
                                                  -----------------------------
                                                  James F. Billett, Jr.
                                                  Chairman, President and
                                                  Chief Executive Officer




Dated:  December 22, 1999

<PAGE>


                                  EXHIBIT INDEX



Exhibit                    Description of Exhibit

2.1      Agreement,   Scheme  of  Arrangement,   Plan  of  Merger  and  Plan  of
         Reorganization, dated as of December 19, 1999, by  and among LaSalle Re
         Holdings  Limited,  LaSalle Re Limited,  Trenwick Group Inc.,  Trenwick
         Group (Delaware) Inc. and Gowin Holdings International Limited.

99.1     Stock Option Agreement, dated as of December 19, 1999, between Trenwick
         Group Inc. and LaSalle Re Holdings  Limited  (option granted to LaSalle
         Re Holdings Limited).

99.2     Stock Option Agreement, dated as of December 19, 1999, between Trenwick
         Group Inc. and LaSalle Re Holdings Limited (option granted to  Trenwick
         Group Inc.).

99.3     Shareholders  Agreement,  dated as of December 19,  1999,  by and among
         Trenwick Group Inc.,  Combined  Insurance Company of America,  Virginia
         Surety Company,  Inc., Aon Risk Consultants (Bermuda) Ltd., Continental
         Casualty Company and CNA (Bermuda) Services Limited.

99.4     Press  release  of Trenwick  Group Inc. and LaSalle Re Holdings Limited
         issued December 19, 1999.














                                   AGREEMENT,
                             SCHEME OF ARRANGEMENT,
                                 PLAN OF MERGER
                                       AND
                             PLAN OF REORGANIZATION
                                  BY AND AMONG
                          LASALLE RE HOLDINGS LIMITED,
                               LASALLE RE LIMITED,
                              TRENWICK GROUP INC.,
                         TRENWICK GROUP (DELAWARE) INC.,
                                       AND
                      GOWIN HOLDINGS INTERNATIONAL LIMITED



                          DATED AS OF DECEMBER 19, 1999




<PAGE>



                                TABLE OF CONTENTS


ARTICLE 1                  CERTAIN DEFINITIONS................................2
         Section 1.1.      Certain Definitions................................2
ARTICLE 2                  THE PLANS..........................................6
         Section 2.1.      The Plans..........................................6
         Section 2.2.      Application to the Court; Shareholder Meetings;
                           Effective Time of the Plans; Closing...............7
         Section 2.3.      Effects of the Plans...............................8
         Section 2.4.      Governing Documents................................9
         Section 2.5.      Board of Directors of New Holdings................10
         Section 2.6.      Terms of the Scheme of Arrangement: Exchange
                           of Securities.....................................10
         Section 2.7.      Terms of the Plan of Merger and the Plan of
                           Reorganization: Conversion and Issuance
                           of Securities.....................................11
         Section 2.8.      Terms of the Scheme of Arrangement: Surrender
                           and Payment.......................................12
         Section 2.9.      Terms of the Plan of Merger and the Plan
                           of Reorganization:
                           Surrender and Payment.............................14
         Section 2.10.     Voting............................................15
         Section 2.11.     Lost Certificates.................................15
         Section 2.12.     No Fractional Shares..............................15

ARTICLE 3                  REPRESENTATIONS AND WARRANTIES OF TRENWICK........16
         Section 3.1.      Corporation; Organization.........................16
         Section 3.2.      Authority; Approval and Fairness..................17
         Section 3.3.      Capital Structure.................................17
         Section 3.4.      SEC Reports; Financial Statements.................19
         Section 3.5.      Absence of Certain Changes or Events..............20
         Section 3.6.      Certain Fees......................................20
         Section 3.7.      No Defaults.......................................20
         Section 3.8.      Consents..........................................21
         Section 3.9.      Compliance with Applicable Law....................21
         Section 3.10.     Information Supplied..............................22
         Section 3.11.     Material Contracts................................22
         Section 3.12.     Taxes.............................................23
         Section 3.13.     Litigation........................................24
         Section 3.14.     Title to Properties; Leases.......................24
         Section 3.15.     Employees.........................................25
         Section 3.16.     Benefit Plans.....................................25
         Section 3.17.     Intellectual Property.............................31
         Section 3.18.     Takeover Statutes.................................32
         Section 3.19.     Opinion of Financial Advisor......................32
         Section 3.20.     Rights Agreement..................................32
         Section 3.21.     Insurance Matters.................................32


<PAGE>



         Section 3.22.     Liabilities and Reserves..........................33
         Section 3.23.     Investment Company................................33
         Section 3.24.     Finite Risk Reinsurance...........................34
         Section 3.25.     Reinsurance Contracts, Coverholders and MGAs......34
         Section 3.26.     Derivatives.......................................35
         Section 3.27.     Related Party Transactions........................35

ARTICLE 4                  REPRESENTATIONS AND WARRANTIES OF LASALLE
                           HOLDINGS..........................................35
         Section 4.1.      Corporation; Organization.........................35
         Section 4.2.      Authority; Approval and Fairness..................36
         Section 4.3.      Capital Structure.................................37
         Section 4.4.      SEC Reports; Financial Statements.................38
         Section 4.5.      Absence of Certain Changes or Events..............39
         Section 4.6.      Certain Fees......................................40
         Section 4.7.      No Defaults.......................................40
         Section 4.8.      Consents..........................................40
         Section 4.9.      Compliance with Applicable Law....................41
         Section 4.10.     Information Supplied..............................41
         Section 4.11.     Material Contracts................................41
         Section 4.12.     Taxes.............................................42
         Section 4.13.     Litigation........................................43
         Section 4.14.     Title to Properties; Leases.......................44
         Section 4.15.     Approval of Scheme of Arrangement.................44
         Section 4.16.     Employees.........................................44
         Section 4.17.     Intellectual Property.............................45
         Section 4.18.     Takeover Statutes.................................46
         Section 4.19.     Opinions of Financial Advisors....................46
         Section 4.20.     Insurance Matters.................................46
         Section 4.21.     Liabilities and Reserves..........................47
         Section 4.22.     Investment Company................................47
         Section 4.23.     Reinsurance Contracts, Coverholders and MGAs......47
         Section 4.24.     Derivatives.......................................48
         Section 4.25.     Related Party Transactions........................48
         Section 4.26.     Finite Risk Reinsurance...........................48

ARTICLE 5                  COVENANTS.........................................49
         Section 5.1.      Conduct of Business of Trenwick...................49
         Section 5.2.      Conduct of Business of LaSalle Holdings...........52
         Section 5.3.      No Solicitation...................................55
         Section 5.4.      Access to Information; Confidentiality............59
         Section 5.5.      Form S-4; Regulatory Matters......................59
         Section 5.6.      Public Announcements..............................60
         Section 5.7.      Supplemental Information..........................60
         Section 5.8.      Shareholders' Meetings............................60


<PAGE>



         Section 5.9.      Trenwick Options, LaSalle Holdings Options,
                           LaSalle Re Options and Trenwick Warrants..........61
         Section 5.10.     Takeover Laws.....................................63
         Section 5.11.     Affiliates........................................63
         Section 5.12.     Stock Exchange Listing............................63
         Section 5.13.     Indemnification and Insurance.....................64
         Section 5.14.     Commercially Reasonable Efforts...................65
         Section 5.15.     Post-Closing Matters..............................65
         Section 5.16.     Employee Benefit Plans; Existing Agreements.......65
         Section 5.17.     Letters from Accountants..........................66
         Section 5.18.     Litigation........................................67
         Section 5.19.     Advice of Changes.................................67
         Section 5.20.     Trenwick Rights Agreement.........................67
         Section 5.21.     New Holdings Rights Agreement.....................67
         Section 5.22.     Organization of Trenwick Subsidiaries.............67
         Section 5.23.     Assumption of Non-Voting Share Conversion
                           Obligation........................................68
         Section 5.24.     Assumption of Series B Preferred Share
                           Conversion Obligation.............................68
         Section 5.25.     Tax-Free Reorganization...........................68

ARTICLE 6                  CONDITIONS TO THE PLANS...........................68
         Section 6.1.      Conditions to Each Party's Obligation to
                           Effect the Plans..................................68
         Section 6.2.      Additional Conditions to Trenwick's Obligation
                           to Effect the Plans...............................70
         Section 6.3.      Additional Conditions to LaSalle Holdings'
                           Obligation to Effect the Plans....................71

ARTICLE 7                  TERMINATION AND ABANDONMENT.......................73
         Section 7.1.      Termination by Trenwick or LaSalle Holdings.......73
         Section 7.2.      Termination by Trenwick...........................74
         Section 7.3.      Termination by LaSalle Holdings...................74
         Section 7.4.      Procedure and Effect of Termination...............75

ARTICLE 8                  MISCELLANEOUS PROVISIONS..........................76
         Section 8.1.      Non-Survival of Representations, Warranties,
                           Covenants and Agreements..........................76
         Section 8.2.      Amendment and Modification........................76
         Section 8.3.      Waiver of Compliance; Consents....................76
         Section 8.4.      Severability and Validity.........................77
         Section 8.5.      Expenses and Obligations..........................77
         Section 8.6.      Parties in Interest...............................77
         Section 8.7.      Notices...........................................77
         Section 8.8.      Governing Law.....................................79
         Section 8.9.      Counterparts......................................79
         Section 8.10.     Headings..........................................79
         Section 8.11.     Entire Agreement; Assignment......................79
         Section 8.12.     Interpretation....................................80


<PAGE>


                             SCHEDULES AND EXHIBITS

         Schedule I        Minority Shareholders
         Exhibit A-1       LaSalle Stock Option Agreement
         Exhibit A-2       Trenwick Stock Option Agreement
         Exhibit B-1       Memorandum of Association of New Holdings
         Exhibit B-2       Bye-Laws of New Holdings
         Exhibit C         New Holdings Directors




<PAGE>




                AGREEMENT, SCHEME OF ARRANGEMENT, PLAN OF MERGER
                           AND PLAN OF REORGANIZATION

         This  Agreement,  Scheme of  Arrangement,  Plan of  Merger  and Plan of
Reorganization (this "Agreement") is made as of the 19th day of December,  1999,
by and among LaSalle Re Holdings Limited,  a company organized under the laws of
Bermuda ("LaSalle Holdings"),  LaSalle Re Limited, a company organized under the
laws of Bermuda and a  majority-owned  Subsidiary (as defined herein) of LaSalle
Holdings   ("LaSalle   Re"),   Trenwick  Group  Inc.,  a  Delaware   corporation
("Trenwick"),  Trenwick Group (Delaware) Inc., a Delaware  corporation and Gowin
Holdings  International  Limited,  a company organized under the laws of Bermuda
("New Holdings").

         WHEREAS,  the issued  share  capital of LaSalle Re  consists  of voting
common  shares,  par value $1.00 per share ("Voting  Shares"),  all of which are
beneficially owned by LaSalle Holdings,  and non-voting common shares, par value
$1.00 per share (the "Non-Voting  Shares"),  all of which are beneficially owned
by LaSalle  Holdings  and the  shareholders  of LaSalle Re listed on  Schedule I
hereto (the "Minority  Shareholders").  LaSalle Holdings owns 15,603,570  Voting
Shares and NonVoting  Shares in the  aggregate.  The Minority  Shareholders  own
4,725,546 Non-Voting Shares in the aggregate (the "Minority Shares").

         WHEREAS,  the  respective  Boards of  Directors  of  LaSalle  Holdings,
LaSalle Re,  Trenwick and New  Holdings  (a) deem it  advisable  and in the best
interests of their  respective  companies  and  shareholders  to enter into this
Agreement   whereby  (i)  each  of  LaSalle   Holdings  and  LaSalle  Re  become
wholly-owned  Subsidiaries of New Holdings pursuant to the Scheme of Arrangement
between LaSalle  Holdings and its shareholders and LaSalle Re and the holders of
its  Non-Voting  Shares  (the  "Scheme of  Arrangement")  and (ii) the assets of
Trenwick  are  transferred  to New  Holdings  pursuant  to a plan of merger  and
restructuring  described in Section  2.1(b) (the "Plan of Merger") and a plan of
reorganization  described in Section 2.1(c) (the "Plan of Reorganization"),  and
together with the Scheme of Arrangement and the Plan of Merger,  the "Plans") as
provided for herein and (b) have adopted  resolutions  approving this Agreement,
the Plans and the transactions contemplated hereby;

         WHEREAS, concurrently with the execution and delivery of this Agreement
and as a condition and  inducement to the  willingness  of LaSalle  Holdings and
Trenwick  to enter into this  Agreement,  LaSalle  Holdings  and  Trenwick  have
entered into (i) a Stock Option Agreement dated as of the date of this Agreement
and  attached  hereto as Exhibit A-1 (the  "LaSalle  Stock  Option  Agreement"),
pursuant to which Trenwick has granted LaSalle  Holdings an option to purchase a
number of shares equal to 19.9% of the currently  outstanding  Common Stock, par
value $0.10 per share, of Trenwick ("Trenwick Shares",  which shall refer to all
such outstanding  shares) and (ii) a Stock Option Agreement dated as of the date
of this Agreement and attached hereto as Exhibit A-2 (the "Trenwick Stock Option
Agreement"  and together  with the LaSalle  Stock Option  Agreement,  the "Stock
Option Agreements"),  pursuant to which LaSalle Holdings has granted Trenwick an
option  to  purchase  a  number  of  shares  equal  to  19.9%  of the  currently
outstanding  Common  Shares,  par value  $1.00 per share,  of  LaSalle  Holdings
("LaSalle Holdings Shares", which shall refer to all such outstanding shares);

                                       1
<PAGE>



         WHEREAS, concurrently with the execution and delivery of this Agreement
and as a condition and  inducement to the  willingness of Trenwick to enter into
this  Agreement,  Trenwick  and the  Minority  Shareholders  have entered into a
Shareholders  Agreement  pertaining  to the voting of shares  held of record and
beneficially in favor of the transactions contemplated hereby; and

         WHEREAS, the parties hereto intend that each of the Plans shall qualify
as tax-free  under the United States  Internal  Revenue Code of 1986, as amended
(the "Code").

         NOW,  THEREFORE,  in  consideration  of the  foregoing  and the  mutual
representations,  warranties,  covenants and agreements  herein  contained,  the
parties hereto agree as follows:


                                   ARTICLE 1.

                               CERTAIN DEFINITIONS

         Section 1.1     Certain Definitions. Certain capitalized terms used in
this Agreement shall have the meaning set forth below:

     (a)   An "Affiliate" of, or a Person "affiliated" with, a specified  Person
means  any  Person   that   directly   or   indirectly,   through  one  or  more
intermediaries, controls, is controlled by, or is under common control with, the
Person specified.

     (b)   "Average  Closing  Price" means an amount  equal to  the  average per
share closing price of a Trenwick Share as reported on the NYSE for the ten (10)
NYSE trading days immediately preceding the three (3) NYSE trading days prior to
the Effective Date (as defined below).

     (c)   "Business Day" means any  day  other  than a Saturday,  a Sunday or a
day on which  commercial  banks in Bermuda or in the State of Connecticut in the
United States of America are authorized or required by law to be closed.

     (d)   "Confidentiality  Letters"  means  the   letter   agreements  between
LaSalle  Holdings  and  Trenwick,  dated as of August 30, 1999 and  November 19,
1999.

     (e)   "Control"  (including,    with   correlative   meanings,   the  terms
"controlling,"  "controlled by" and "under common control  with"),  as used with
respect to any Person, means the possession, direct or indirect, of the power to
direct or cause the  direction  of the  management  or policies of such  Person,
whether through the ownership of voting securities, by agreement or otherwise.

     (f)   "Dollars" or "$" means  the  lawful currency  of the United States of
America.


                                       2

<PAGE>


     (g)   "Effective Time" means the later of the Scheme Effective Time and the
Reorganization Effective Time.

     (h)   "Employee Benefit Plan" means

                           (a) any "employee  welfare benefit plan" or "employee
                           pension  benefit plan" (as those terms are defined in
                           sections 3(1) and 3(2) of ERISA, respectively), other
                           than a  "multiemployer  plan" (as  defined in Section
                           3(37) of ERISA);

                           (b) any  retirement  or deferred  compensation  plan,
                           incentive compensation plan, stock plan, unemployment
                           compensation plan, vacation pay, severance pay, bonus
                           or benefit arrangement,  insurance or hospitalization
                           program or any other fringe benefit  arrangements for
                           any current or former employee, director,  consultant
                           or agent, whether pursuant to contract,  arrangement,
                           custom  or  informal  understanding,  which  does not
                           constitute  an employee  benefit  plan (as defined in
                           Section 3(3) of ERISA); or

                           (c) any employment agreement or consulting agreement.

     (i) "ERISA" means the United States Employee Retirement Income Security Act
of 1974, as amended.

     (j) "Exchange Act" means the United States Securities Exchange Act of 1934,
as amended.

     (k) "GAAP" means generally accepted accounting  principles as in effect  in
the United  States of America  (as such  principles  may change  from time to
time).

     (l) "Governmental Authority" means  any  governmental,  quasi-governmental,
judicial or regulatory agency or entity or subdivision thereof with jurisdiction
over  Trenwick,  LaSalle  Holdings,  LaSalle  Re, New  Holdings  or any of their
respective  Subsidiaries  or  any  of  the  transactions  contemplated  by  this
Agreement   (including,   without   limitation,   the   Corporation  of  Lloyd's
("Lloyd's")).

     (m) "Knowledge" (i) an individual will be considered  to  have  "Knowledge"
of a fact or matter if the  individual is actually  aware of the fact or matter;
(ii) an entity will be considered to have "Knowledge" of a fact or matter if any
individual who is serving,  or who has at any time served, as a senior executive
of such  entity has, or at any time had,  Knowledge  of the fact or matter;  and
Trenwick and LaSalle  Holdings will be considered to have  "Knowledge" of a fact
or  matter  if  Trenwick  or  its   Subsidiaries  or  LaSalle  Holdings  or  its
Subsidiaries, as the case may be, has Knowledge of the fact or matter.









                                       3

<PAGE>


     (n)  "LaSalle Disclosure Letter" means  the  letter, dated  as  of the date
hereof,  from LaSalle Holdings to Trenwick  regarding certain matters related to
this Agreement.

     (o)  "LaSalle Fair Market  Value"  means the  product of (i) the average of
the closing  sale price as reported  on the NYSE  Composite  Tape for the Voting
Shares for the thirty (30) trading days immediately preceding the Effective Date
multiplied by (ii) the  aggregate number of issued and outstanding Voting Shares
and Non-Voting  Shares on the Effective Date.

     (p) "Lien" means any mortgage, lien, security interest,  pledge,  lease or
other charge or encumbrance of any kind, including, without limitation, the lien
or retained  security title of a purchase money creditor or conditional  vendor,
and any easement,  right of way or other  encumbrance on title to real property,
and any agreement to give any of the foregoing.

     (q) "Material  Adverse  Change" or "Material  Adverse Effect" means,  with
respect to any Person,  any change,  effect,  event,  condition or  development,
occurrence or state of facts that is materially adverse to the business, assets,
results of  operations,  properties,  financial or  operating  condition of such
party  and  its  Subsidiaries,  taken  as a  whole  or the  ability  to  perform
obligations under this Agreement;  provided,  however, that any change,  effect,
event, condition or development,  occurrence or state of facts resulting from or
arising in connection  with (i) this Agreement,  the Scheme of Arrangement,  the
Plan  of  Merger  or  the  transactions   contemplated   hereby  or  the  public
announcement   thereof,   (ii)  changes   generally   affecting  the  insurance,
reinsurance or financial services industry (including,  without limitation,  the
impact  of any  natural  catastrophes  causing  a Net Loss  from a  single  loss
occurrence  and not in the  aggregate to such Persons of  $100,000,000  or less,
(iii) changes in the value of portfolio  investments  resulting  from changes in
prevailing  interest  rates,  (iv)  changes  in  economic  or market  conditions
generally,  (v)  changes  in  laws,  regulations,   accounting  principles,   or
regulations or policies of general  applicability or (vi) changes resulting from
actions or omissions of a party hereto taken with the prior  written  consent of
the other  parties in  contemplation  of the Scheme of  Arrangement  and Plan of
Merger and associated  transactions  contemplated  by this  Agreement  shall not
constitute a Material Adverse Effect for purposes of this Agreement.

     (r)  "Net Loss"  means,  with respect to any Person,  the estimated  amount
of all losses and loss  adjustment  expenses  incurred or to be incurred by such
Person  and its  Subsidiaries  in  connection  with the  occurrence  of a single
natural  catastrophe  occurring  between the date hereof and the Effective Time,
net of all applicable  reinsurance  recoverables,  determined in accordance with
GAAP and generally  accepted  actuarial  standards of practice as applied in the
insurance  industry,  each as in effect on the date of determination of such Net
Loss. Net Loss shall be determined as soon as reasonably  practicable  following
the occurrence of a natural  catastrophe by the Settlement Auditor. In the event
that there is more than one Person serving as the Settlement  Auditor,  Net Loss
shall be  determined  by  taking  the  average  of the Net  Loss  determinations
established by each Settlement Auditor.

     (s)   "NYSE" means The New York Stock Exchange, Inc.





                                       4

<PAGE>

     (t) "Permitted Liens" means, with respect to Trenwick  or LaSalle  Holdings
(as the case may be),  (i) Liens for Taxes or other  assessments  or  charges of
Governmental Authorities that are not yet delinquent or that are being contested
in good faith by appropriate  proceedings,  in each case,  with respect to which
adequate  reserves or other  appropriate  provisions are being maintained to the
extent  required by GAAP;  (ii)  statutory  Liens of landlords and mortgagees of
landlords and Liens of carriers, warehousemen,  mechanics, materialmen and other
Liens imposed by law and created in the ordinary  course of business for amounts
not yet more than thirty (30) days overdue or which are being  contested in good
faith by appropriate  proceedings,  in each case, with respect to which adequate
reserves or other  appropriate  provisions  are being  maintained  to the extent
required  by  GAAP;  (iii)  leases  or  subleases,   easements,   rights-of-way,
covenants,  consents  and  Liens  which  do not  interfere  materially  with the
ordinary  conduct of the  business of Trenwick or LaSalle  Holdings (as the case
may  be) and  their  respective  Subsidiaries,  taken  as a  whole,  or  detract
materially  from the value of the  property to which they  attach or  materially
impair  the use  thereof  to such  party and its  Subsidiaries;  and (iv)  Liens
granted by  Trenwick  or LaSalle  Holdings  (as the case may be) or any of their
respective Subsidiaries to lenders pursuant to credit agreements in existence on
the date hereof.

     (u) "Person"  means any  individual, company, corporation, estate,  limited
liability company, partnership, joint venture, association, joint stock company,
trust,  unincorporated  organization  or  government  or any agency or political
subdivision thereof or other entity.

     (v)  SEC" means the United States Securities and Exchange Commission.

     (w)  "Securities Act" means  the United States Securities Act of 1933, as
amended.

     (x)  "Settlement  Auditor"  means either Ernst & Young LLP or Paragon Risk
Management  Services,  Inc., as shall be mutually agreed by LaSalle Holdings and
Trenwick.  In the event LaSalle Holdings and Trenwick are unable to agree upon a
Settlement Auditor within 30 calendar days following the completion of a natural
catastrophe,  both Ernst & Young LLP and Paragon Risk Management Services,  Inc.
shall serve as the Settlement Auditor.

     (y) "Subsidiary"  means, with  respect to a specified  Person, each company
partnership  or other  entity in which the  specified  Person owns or  controls,
directly or indirectly through one or more  intermediaries,  fifty percent (50%)
or more of the shares or other  interests  having  general  voting  power in the
election of directors or Persons performing similar functions or rights to fifty
percent (50%) or more of any distributions.

     (z)  "Tax" or "Taxes"  means any Bermuda or United  States  federal, state,
local,  foreign or other income,  share capital,  employees' income withholding,
foreign Person  withholding,  social security,  unemployment,  disability,  real
property,  personal  property,  sales, use, transfer or other tax, including any
interest,  penalties  or other  additions  to tax in respect  to the  foregoing,
whether disputed or not.

     (aa)  "Trenwick  Delaware"  means Trenwick Group  (Delaware)  Inc., a
newly-formed  holding company organized under the laws of the State of Delaware,
all of whose  outstanding  shares  of  capital  stock  are  owned  initially  by
Trenwick,  with  Certificate  of  Incorporation,  By-laws and capital  structure
identical in all material respects to those of Trenwick.




                                       5

<PAGE>


     (bb)  "Trenwick  Delaware  Shares" means the shares of common stock,
par value $.10 per share, of Trenwick Delaware outstanding from time to time.

     (cc) "Trenwick  Disclosure Letter" means the letter,  dated as of the
date hereof, from Trenwick  to  LaSalle  Holdings   regarding  certain  matters
related  to  this Agreement.

     (dd) "Trenwick Fair Market Value" means the product of (i) the average
of the  closing  sale  price  as  reported  on the NYSE  Composite  Tape for the
Trenwick  Shares for the thirty (30)  trading  days  immediately  preceding  the
Effective Date multiplied by (ii) the number of issued and outstanding  Trenwick
Shares on the Effective Date.

     (ee) "Trenwick  Holdings Limited" means a wholly-owned  subsidiary of
Trenwick organized under the laws of the United Kingdom.

     (ff) "Trenwick LLC" means a Delaware limited liability company with a
single membership interest outstanding and held by Trenwick Delaware.

     (gg)  "Trenwick Services Limited" means a wholly-owned subsidiary of
Trenwick organized under the laws of Bermuda.

     (hh)  "Trenwick  Subsidiary"  means  a  wholly-owned   subsidiary  of
Trenwick Delaware organized under the laws of the State of Delaware.


                                    ARTICLE 2

                                    THE PLANS

     Section 2.1      The Plans.

         (a) The  Scheme of  Arrangement.  On the  Effective  Date at the Scheme
Effective  Time (as  defined  herein),  and upon the  terms and  subject  to the
conditions  hereof and  subject to the  Supreme  Court of the Islands of Bermuda
(the  "Court")   exercising  its  discretion  and   sanctioning  the  Scheme  of
Arrangement  pursuant to Section 99(2) of The Companies Act, 1981 of Bermuda, as
amended  (the  "Companies  Act"),  and making  such  facilitating  orders as are
appropriate  pursuant to Section 101 of the Companies Act, all of the issued and
outstanding  LaSalle  Holdings  Shares  and all of the  issued  and  outstanding
Minority  Shares shall be  transferred  to New Holdings,  and holders of LaSalle
Holdings Shares and Minority Shares shall become holders of common shares of New
Holdings ("New Holdings Shares") in accordance with the terms of this Agreement.




                                        6

<PAGE>

         (b) The Plan of Merger.  On the Effective  Date,  immediately  prior to
(but subject to the  consummation  of) the Plan of  Reorganization  described in
Section  2.1(c),  and upon the  terms  and  subject  to the  conditions  of this
Agreement:

                  (i) At the Merger Effective Time (as defined herein), Trenwick
                  shall merge with and into  Trenwick  LLC,  pursuant to Section
                  264 of the General  Corporation  Law of the State of Delaware,
                  as amended (the  "GCL"),  with  Trenwick LLC as the  surviving
                  entity, whereupon the shareholders of Trenwick shall receive a
                  number of  Trenwick  Delaware  Shares  equal to the  number of
                  Trenwick Shares owned by them in a
                  transaction  intended to qualify as a tax-free  reorganization
                  under  Section  368(a) of the Code.  At the  Merger  Effective
                  Time, the one share of common stock of Trenwick Delaware owned
                  by Trenwick shall be cancelled;

                  (ii) Trenwick LLC shall distribute to Trenwick  Delaware all
                  of the issued and outstanding shares of Trenwick Holdings
                  Limited and Trenwick Services Limited;

                  (iii)  Trenwick Delaware shall  assume  all  undertakings  and
                  obligations  of Trenwick  under this  Agreement and, upon such
                  assumption  for the purposes of Section 2.1(c) and the Plan of
                  Reorganization  and  transactions  contemplated  thereby,  all
                  references to Trenwick,  Trenwick Shares, Trenwick Options and
                  any  other  similar   reference,   respectively,   under  this
                  Agreement shall refer to Trenwick Delaware,  Trenwick Delaware
                  Shares,  options to acquire  Trenwick  Delaware  Shares and to
                  such similar reference, respectively; and

                  (iv) Trenwick Delaware shall contribute to Trenwick Subsidiary
                  its entire interest in Trenwick LLC.

         (c) The Plan of  Reorganization.  On the Effective Date, upon the terms
and subject to the conditions  hereof and immediately after and conditioned upon
the transactions set forth in Section 2.1(b),  New Holdings shall acquire all of
the assets of and shall assume all of the  liabilities of Trenwick,  pursuant to
Section 271 of the GCL,  in  exchange  for New  Holdings  Shares  which shall be
distributed  to the  holders of Trenwick  Shares (the time of such  distribution
being the "Reorganization  Effective Time") in complete liquidation of Trenwick,
in a transaction intended to qualify as a tax-free  reorganization under Section
368(a) of the Code.

         Section 2.2  Application to the Court;  Shareholder  Meetings;
Effective Time of the Plans; Closing.

         (a) As soon as practicable after the date hereof,  LaSalle Holdings and
LaSalle Re, acting through their respective  Boards of Directors,  in accordance
with applicable law shall:




                                       7

<PAGE>


                  (i) cause an application to be made to the Court,  pursuant to
                  Section 99(1) of the Companies  Act,  requesting  the Court to
                  summon such class meetings of members of LaSalle  Holdings and
                  LaSalle Re as the Court may direct;

                  (ii) give notice of, convene and hold such class  meetings for
                  the  purpose  of  obtaining  such  approvals  of the Scheme of
                  Arrangement  as may be  required  under  Section  99(2) of the
                  Companies Act; and

                  (iii) subject to such approvals being obtained, cause a
                  petition to be presented to the Court seeking the sanctioning
                  of the Scheme of Arrangement  pursuant to Section 99 of the
                  Companies Act and file such other  documents  as are required
                  to be duly filed with the Court to effect the Scheme of
                  Arrangement.

         (b) As soon as  practicable  after the date  hereof,  Trenwick,  acting
through its Board of Directors,  in accordance  with  applicable law shall duly
call, give notice of, convene  and hold an annual  or  special  meeting  of its
stockholders  for the purpose of obtaining  their approval of this  Agreement,
the Plan of Merger and the Plan of Reorganization.

         (c) Upon  receipt of orders  from the Court  sanctioning  the Scheme of
Arrangement,  upon approval by the  stockholders  of Trenwick of this Agreement,
the Plan of Merger and the Plan of Reorganization and upon the terms and subject
to the satisfaction or waiver, if permissible, of the conditions hereof, (i) the
order  sanctioning  the  Scheme  of  Arrangement  shall be duly  filed  with the
Registrar of Companies of Bermuda (the  "Registrar")  and (ii) a certificate  of
merger with respect to this  Agreement and the Plan of Merger (the  "Certificate
of Merger")  shall be duly filed with the  Secretary  of State of Delaware  (the
"Secretary of State"). The Scheme of Arrangement shall become effective upon the
filing of the order of the Court with respect to the Scheme of Arrangement  with
the Registrar (the time of such filing being the "Scheme Effective Time" and the
date of such filing being the "Effective Date"). The Plan of Merger shall become
effective  upon the filing of the  Certificate  of Merger with the  Secretary of
State  (the  "Merger   Effective   Time")  on  the  Effective   Date,  with  the
Reorganization Effective Time being immediately after the Merger Effective Time.
Immediately  prior to such filings,  a closing (the "Closing")  shall be held at
such  time as the last  condition  set forth  hereunder  shall be  fulfilled  or
waived, at the New York office of Mayer, Brown & Platt, 1675 Broadway, New York,
New York 10019-5820, at 9:00 a.m. or such other place and/or time as the parties
shall agree,  for the purpose of confirming  the  satisfaction  or waiver of the
conditions  set forth in Article 5. The date upon which the Closing  shall occur
is referred to herein as the "Closing Date."

         Section 2.3  Effects of the Plans.

         (a) Effect of the  Scheme of  Arrangement.  As of the Scheme  Effective
Time,  LaSalle  Holdings shall be a wholly-owned  Subsidiary of New Holdings and
LaSalle  Re shall be,  directly  and  indirectly  through  LaSalle  Holdings,  a
wholly-owned  Subsidiary of New Holdings, and holders of LaSalle Holdings Shares
and  Minority   Shares  shall  only  have  the  right  to  receive  the  LaSalle
Consideration as set forth in Section 2.6(c).



                                       8

<PAGE>

         (b) Effect of the Plan of Merger and the Plan of Reorganization.  As of
the  Reorganization  Effective Time,  Trenwick shall have transferred all of its
assets to New Holdings and New Holdings  shall have assumed all the  liabilities
of  Trenwick  and the holders of  Trenwick  Shares  shall only have the right to
receive the Trenwick Consideration as set forth in Section 2.7(b).

         Section 2.4     Governing Documents.

         (a)      New Holdings.

                  (i) At or prior to the Closing,  the memorandum of association
                  of New Holdings shall be in the form set forth in Exhibit B(i)
                  attached hereto.

                  (ii) At or prior to the  Closing, the bye-laws of New Holdings
                  shall be in the  form set  forth  in  Exhibit  B(ii)  attached
                  hereto.

        (b)       LaSalle Holdings.

                  (i) The  memorandum  of  association  of LaSalle  Holdings  in
                  effect at the Scheme  Effective  Time shall continue to be the
                  memorandum of association of LaSalle Holdings until thereafter
                  amended or restated as provided therein and by law.

                  (ii) The bye-laws of LaSalle  Holdings in effect at the Scheme
                  Effective  Time,  shall continue to be the bye-laws of LaSalle
                  Holdings  until  thereafter  amended or  restated  as provided
                  therein and by law.

         (c)      LaSalle Re.

                  (i) The  memorandum of  association of LaSalle Re in effect at
                  the Scheme  Effective Time shall continue to be the memorandum
                  of  association  of  LaSalle  Re until  thereafter  amended or
                  restated as provided therein and by law.

                  (ii)  The bye-laws  of  LaSalle  Re in  effect  at the  Scheme
                  Effective Time shall continue to be the bye-laws of LaSalle Re
                  until  thereafter  amended or restated as provided therein and
                  by law.



                                       9

<PAGE>


         (d)      Trenwick Delaware

                  (i) The certificate of incorporation  of Trenwick  Delaware in
                  effect at the Merger  Effective  Time shall continue to be the
                  certificate  of  incorporation  of  Trenwick   Delaware  until
                  thereafter amended or restated as provided therein and by law.

                  (ii) The by-laws of Trenwick  Delaware in effect at the Merger
                  Effective  Time shall  continue  to be the by-laws of Trenwick
                  Delaware  until  thereafter  amended or  restated  as provided
                  therein and by law.

         (e)      Trenwick LLC

                  (i) The  certificate of formation of Trenwick LLC in effect at
                  the Merger Effective Time shall continue to be the certificate
                  of formation of the surviving entity until thereafter  amended
                  or restated as provided therein and by law.

                  (ii)  The limited  liability  company  agreement  of  Trenwick
                  Delaware in effect at the Merger Effective Time shall continue
                  to be the limited liability company agreement of the surviving
                  entity  until  thereafter  amended  or  restated  as  provided
                  therein and by law.

     Section 2.5   Board of Directors of New Holdings. The parties hereto shall
procure  that at or prior to the  Closing,  the  directors  of New Holdings
shall be the  individuals  designated in Exhibit C attached  hereto,  which such
directors shall constitute the entire Board of Directors of New Holdings at such
time,  each of such  directors to hold office in accordance  with the applicable
provisions  of the byelaws of New Holdings and until their  successors  shall be
elected or appointed and shall duly qualify.


     Section 2.6   Terms of the Scheme of Arrangement:  Exchange of Securities.
At the Scheme  Effective  Time, by virtue of the Scheme of Arrangement  and
without any action on the part of LaSalle  Holdings,  LaSalle Re or the holder
of any of the following securities:

         (a)  Subject to  Section  2.12,  each LaSalle  Holdings  Share and each
Minority Share that is issued and  outstanding  immediately  prior to the Scheme
Effective  Time (other than LaSalle  Holdings  Shares and Minority  Shares to be
cancelled  in  accordance  with  Section  2.6(c))  shall be  transferred  to New
Holdings  and there  shall be  allotted  and issued to the holder  thereof  such
number of fully paid and  nonassessable  New Holdings  Shares as is equal to the
LaSalle  Exchange  Ratio,  as defined below (the "LaSalle  Consideration").  The
"LaSalle  Exchange  Ratio" means the product of (i) 1.0  multiplied  by (ii) the
quotient of (A) the LaSalle  Fair Market  Value minus 50% of the amount by which
any Net Loss  experienced by LaSalle  Holdings  exceeds  $40,000,000 and is less
than or equal to $60,000,000  and minus 100% of the amount by which any Net Loss
experienced by LaSalle Holdings exceeds $60,000,000 and is less than or equal to
$100,000,000,  divided by (B) the LaSalle Fair Market Value.  New Holdings shall
issue the New  Holdings  Shares to be  received  as  LaSalle  Consideration  and
register  the Persons to whom New  Holdings  Shares are issued on New  Holdings'
register of members. The Non-Voting Shares held by LaSalle Holdings shall not be
affected by the Scheme of Arrangement.



                                       10

<PAGE>

         (b) Each LaSalle  Holdings  Option (as defined herein) and each LaSalle
Re Option (as defined herein)  outstanding as of the Scheme Effective Time shall
be treated in accordance with the provisions of Section 5.9.

         (c) Each  LaSalle  Holdings  Share  that is  issued  and  outstanding
immediately  prior to the  Effective  Time  that is owned by  LaSalle  Holdings,
LaSalle Re, Trenwick,  New Holdings or any Subsidiary of either of the foregoing
shall be  automatically  cancelled and retired and shall cease to exist,  and no
cash or other  consideration  shall be  delivered  or  deliverable  in  exchange
therefor.

         (d)  Each Series A  Preferred  Share of LaSalle  Holdings or LaSalle Re
that is issued and  outstanding  immediately  prior to the Effective  Time shall
remain  unchanged as a Series A Preferred  Share of LaSalle  Holdings or LaSalle
Re, as the case may be.

        (e) If the requisite approval of the holders of Non-Voting Shares is not
received, the Scheme of Arrangement shall relate only to LaSalle Holdings Shares
and shall not affect the NonVoting Shares.

     Section 2.7  Terms  of the  Plan  of  Merger  and the  Plan  of
Reorganization: Conversion and Issuance of Securities.

         (a) At the Merger  Effective  Time,  by virtue of the Plan of Merger
and  without  any  action on the part of any of the  entities  described  in
Section 2.1(b) or the holder of any of the following securities:

                  (i)  Each  Trenwick  Share  that  is  issued  and  outstanding
                  immediately  prior to the Merger  Effective  Time  (other than
                  Trenwick  Shares to be  cancelled in  accordance  with Section
                  2.7(d)) shall be cancelled and extinguished and converted into
                  the right to receive one fully paid and nonassessable Trenwick
                  Delaware Share.  If prior to the Merger  Effective Time either
                  Trenwick,  LaSalle  Holdings  or  LaSalle  Re should  split or
                  combine  the  Trenwick  Shares,  the  LaSalle Re Shares or the
                  Minority  Shares,  as  applicable,  pay a  stock  dividend  or
                  otherwise change the Trenwick Shares, the LaSalle Re Shares or
                  the Minority Shares, as applicable, into any other securities,
                  or make any other  dividend or  distribution  on the  Trenwick
                  Shares,  the  LaSalle  Re Shares or the  Minority  Shares,  as
                  applicable,   then  the  Trenwick   Exchange   Ratio  will  be
                  appropriately  adjusted to reflect  such  split,  combination,
                  dividend or other  distribution or changes.  Trenwick Delaware
                  shall  issue the  Trenwick  Delaware  Shares to be received as
                  Trenwick  Delaware  Consideration  and register the Persons to
                  whom such  Trenwick  Delaware  Shares are  issued in  Trenwick
                  Delaware's register of stockholders.



                                       11

<PAGE>


                  (ii)  Each Trenwick Option (as defined herein) outstanding as
                  of the Merger  Effective Time shall be treated in accordance
                  with the provisions of Section 5.9.

                  (iii) Each Trenwick  Share  that  is  issued  and  outstanding
                  immediately  prior to the Merger  Effective Time that is owned
                  by LaSalle Holdings, LaSalle Re, Trenwick, New Holdings or any
                  Subsidiary  of any of the foregoing  (together,  in each case,
                  with the associated Right (as defined in Section 3.3(a)) shall
                  be  automatically  cancelled  and  retired  and shall cease to
                  exist, and no cash or other  consideration  shall be delivered
                  or deliverable in exchange therefor.

          (b)  Subject to Section 2.12, at the Reorganization Effective Time, by
virtue of the Plan of  Reorganization  and without any action on the part of any
of  the  entities  described  in  Section  2.1(c)  or the  holder  of any of the
following  securities,  there  shall be  allotted  and issued to each  holder of
Trenwick  Delaware Shares a number of fully paid and  nonassessable New Holdings
Shares  as is equal to the  Trenwick  Exchange  Ratio,  as  defined  below  (the
"Trenwick  Consideration").  The "Trenwick  Exchange Ratio" means the product of
(i) 1.0  multiplied  by (ii) the quotient of (A) the Trenwick  Fair Market Value
minus 50% of the amount by which any Net Loss  experienced  by Trenwick  exceeds
$40,000,000  and is less  than or equal to  $60,000,000  and  minus  100% of the
amount by which any Net Loss experienced by Trenwick exceeds  $60,000,000 and is
less than or equal to  $100,000,000,  divided by (B) the  Trenwick  Fair  Market
Value.  New  Holdings  shall  issue the New  Holdings  Shares to be  received as
Trenwick Consideration and register the Persons to whom such New Holdings Shares
are issued in New Holdings' register of members.

     Section 2.8   Terms of the Scheme of Arrangement: Surrender and Payment.

         (a) Promptly  after the Scheme  Effective  Time, New Holdings shall (i)
appoint  an  agent  (the  "LaSalle  Exchange  Agent")  for the  purpose  of
exchanging certificates representing LaSalle Holdings Shares and Minority Shares
for New  Holdings  Shares  pursuant to Section  2.6(a),  (ii)  deposit  with the
LaSalle  Exchange  Agent   certificates   representing  the  aggregate   LaSalle
Consideration  to be paid in  respect  of the  LaSalle  Holdings  Shares and the
Minority  Shares  (together  with any  dividends or  distributions  with respect
thereto) and (iii) send,  or cause the LaSalle  Exchange  Agent to send, to each
holder of LaSalle  Holdings  Shares and each  holder of  Minority  Shares at the
Scheme  Effective Time a letter of transmittal  for use in such exchange  (which
shall  specify that the delivery  shall be effected,  and risk of loss and title
shall pass, only upon proper delivery of the certificates  representing  LaSalle
Holdings  Shares or Minority  Shares (as  applicable)  to the  LaSalle  Exchange
Agent).

         (b) Each holder of LaSalle Holdings Shares or Minority Shares that have
been  transferred to New Holdings  pursuant to the Scheme of  Arrangement,  upon
surrender  to the  LaSalle  Exchange  Agent  of a  certificate  or  certificates
representing  such  shares,   together  with  a  properly  completed  letter  of
transmittal  covering  such  shares,  shall be  entitled  to receive the LaSalle
Consideration payable in respect of such shares. Until so surrendered, each such
certificate shall,  after the Scheme Effective Time,  represent for all purposes
only the right to receive such LaSalle Consideration.



                                       12

<PAGE>


         (c) If any  portion  of the  LaSalle  Consideration  is to be paid to a
Person  other  than the  registered  holder of the  LaSalle  Holdings  Shares or
Minority Shares (as  applicable)  represented by the certificate or certificates
surrendered in exchange  therefor,  it shall be a condition to such payment that
the  certificate or certificates  so surrendered  shall be properly  endorsed or
otherwise  be in proper form for transfer  and that the Person  requesting  such
payment  shall pay to the  LaSalle  Exchange  Agent any  transfer or other Taxes
required  as a result of such  payment  to a Person  other  than the  registered
holder of such shares or establish to the  satisfaction of the LaSalle  Exchange
Agent that such Tax has been paid or is not payable.

         (d)  After  the  Scheme  Effective  Time,  there  shall  be no  further
registrations  of transfers of LaSalle  Holdings Shares or Minority Shares other
than the registration of LaSalle Holdings Shares and Minority Shares in the name
of New Holdings pursuant to Section 2.6(a). If, after the Scheme Effective Time,
certificates  representing  LaSalle  Holdings  Shares  or  Minority  Shares  are
presented to LaSalle  Holdings or, subject to the provisions of Section  2.8(e),
the LaSalle  Exchange  Agent,  they shall be  cancelled  and  exchanged  for the
LaSalle  Consideration  in  accordance  with the  procedures  set  forth in this
Section 2.8.

         (e)  Any  portion  of the  LaSalle  Consideration  (together  with  any
dividends or distributions  with respect to the New Holdings  Shares)  deposited
with the LaSalle  Exchange Agent pursuant to Section 2.8(a) and any cash payment
for a  fractional  New Holdings  Share  pursuant to Section  2.12,  that remains
unclaimed by the holders of LaSalle  Holdings  Shares or the holders of Minority
Shares  twelve months after the Scheme  Effective  Time shall be returned to New
Holdings or an Affiliate  designated by New Holdings,  upon demand, and any such
holder who has not exchanged his LaSalle  Holdings Shares or Minority Shares for
the LaSalle Consideration in accordance with this Section 2.8 prior to that time
shall thereafter look only to New Holdings for his claim for New Holdings Shares
and  any  dividends  or  distributions  with  respect  to New  Holdings  Shares.
Notwithstanding the foregoing, New Holdings shall not be liable to any holder of
LaSalle  Holdings Shares or any holder of Minority Shares for any amount paid to
a public official pursuant to applicable abandoned property laws.

         (f) No  dividends  or  other  distributions  with  respect  to the  New
Holdings Shares constituting part of the LaSalle  Consideration shall be paid to
the  holder of any  unsurrendered  certificates  representing  LaSalle  Holdings
Shares or Minority Shares until such certificates are surrendered as provided in
this Section 2.8. Upon such surrender, there shall be paid, without interest, to
the Person in whose name the  certificates  representing the New Holdings Shares
received in exchange for such  LaSalle  Holdings  Shares or Minority  Shares (as
applicable) are registered, (i) all dividends and other distributions in respect
of New Holdings  Shares that are payable on a date subsequent to, and the record
date for which occurs after, the Scheme Effective Time and (ii) all dividends or
other distributions in respect of LaSalle Holdings Shares or Minority Shares (as
applicable)  that are payable on a date  subsequent  to, and the record date for
which occurs on or before, the Scheme Effective Time.



                                       13

<PAGE>


         (g)  At  and  after  the  Scheme  Effective  Time,  each  holder  of  a
certificate or certificates  that  represented  issued and  outstanding  LaSalle
Holdings Shares or Minority  Shares  immediately  prior to the Scheme  Effective
Time shall  cease to have any rights as a  shareholder  of LaSalle  Holdings  or
LaSalle Re (as applicable), except for the right to surrender its certificate or
certificates  in  exchange  for the  LaSalle  Consideration  as provided in this
Section 2.8.

     Section 2.9  Terms  of the  Plan  of  Merger  and the  Plan  of
Reorganization: Surrender and Payment.

         (a) Promptly  after the  Reorganization  Effective  Time,  New Holdings
shall (i) appoint an agent (the  "Trenwick  Exchange  Agent") for the purpose of
exchanging  certificates  representing  Trenwick  Shares for New Holdings Shares
pursuant  to  Section  2.7,  (ii)  deposit  with  the  Trenwick  Exchange  Agent
certificates  representing  the aggregate  Trenwick  Consideration to be paid in
exchange for the Trenwick Shares  (together with any dividends or  distributions
with respect  thereto) and (iii) send, or cause the Trenwick  Exchange  Agent to
send, to each holder of Trenwick Shares at the  Reorganization  Effective Time a
letter of  transmittal  for use in such  exchange  (which shall specify that the
delivery  shall be  effected,  and risk of loss and title shall pass,  only upon
proper delivery of the certificates representing Trenwick Shares to the Trenwick
Exchange Agent).

         (b) Each holder of  Trenwick  Shares  that have been  converted  into a
right to receive the Trenwick  Consideration  pursuant to the Plan of Merger and
the Plan of  Reorganization,  upon surrender to the Trenwick Exchange Agent of a
certificate or certificates  representing such Trenwick Shares,  together with a
properly completed letter of transmittal covering such Trenwick Shares, shall be
entitled  to  receive  the  Trenwick  Consideration  payable  in respect of such
Trenwick Shares.  Until so surrendered,  each such certificate  shall, after the
Reorganization  Effective  Time,  represent  for all purposes  only the right to
receive such Trenwick Consideration.

         (c) If any  portion of the  Trenwick  Consideration  is to be paid to a
Person other than the registered holder of the Trenwick Shares  represented
by the certificate or certificates surrendered in exchange therefor, it shall be
a condition to such payment that the  certificate or certificates so surrendered
shall be properly  endorsed or otherwise be in proper form for transfer and that
the Person  requesting such payment shall pay to the Trenwick Exchange Agent any
transfer or other Taxes  required as a result of such  payment to a Person other
than  the  registered  holder  of  such  Trenwick  Shares  or  establish  to the
satisfaction  of the Trenwick  Exchange  Agent that such Tax has been paid or is
not payable.

         (d) After the Reorganization  Effective Time, there shall be no further
registrations  of transfers  of Trenwick  Shares.  If, after the  Reorganization
Effective  Time,  certificates  representing  Trenwick  Shares are  presented to
Trenwick or, subject to the provisions of Section 2.9(e),  the Trenwick Exchange
Agent,  they shall be cancelled and exchanged for the Trenwick  Consideration in
accordance with the procedures set forth in this Section 2.9.



                                       14

<PAGE>

         (e) Any  portion  of the  Trenwick  Consideration  (together  with  any
dividends or distributions  with respect to the New Holdings  Shares)  deposited
with the  Trenwick  Exchange  Agent  pursuant  to Section  2.9(a),  and any cash
payment for a  fractional  New Holdings  Share  pursuant to Section  2.12,  that
remains  unclaimed  by the holders of Trenwick  Shares  twelve  months after the
Reorganization  Effective Time shall be returned to New Holdings or an Affiliate
designated  by New  Holdings,  upon  demand,  and any  such  holder  who has not
exchanged his Trenwick Shares for the Trenwick  Consideration in accordance with
this Section 2.9 prior to that time shall  thereafter  look only to New Holdings
for his  claim  for New  Holdings  Shares,  any cash in lieu of  fractional  New
Holdings Shares and any dividends or distributions  with respect to New Holdings
Shares.  Notwithstanding the foregoing,  New Holdings shall not be liable to any
holder of Trenwick Shares for any amount paid to a public  official  pursuant to
applicable abandoned property laws.

         (f) No  dividends  or  other  distributions  with  respect  to the  New
Holdings Shares constituting part of the Trenwick Consideration shall be paid to
the holder of any unsurrendered  certificates representing Trenwick Shares until
such  certificates  are  surrendered  as provided in this Section 2.9. Upon such
surrender,  there shall be paid,  without interest,  to the Person in whose name
the  certificates  representing the New Holdings Shares into which such Trenwick
Shares were converted are registered,  (i) all dividends and other distributions
in respect of New Holdings  Shares that are payable on a date subsequent to, and
the record date for which occurs after,  the  Reorganization  Effective Time and
(ii) all dividends or other distributions in respect of Trenwick Shares that are
payable on a date  subsequent  to, and the  record  date for which  occurs on or
before, the Merger Effective Time.

         (g)  At  and  after  the  Merger  Effective  Time,  each  holder  of  a
certificate or certificates  that  represented  issued and outstanding  Trenwick
Shares  immediately  prior to the Merger  Effective Time shall cease to have any
rights as a  stockholder  of  Trenwick,  except for the right to  surrender  its
certificate  or  certificates  in exchange  for the  Trenwick  Consideration  as
provided in this Section 2.9.

     Section 2.10   Voting.  In  determining  shareholders  of New Holdings
entitled  to  notice  of and to vote at  meetings  of  shareholders  of New
Holdings,  former  shareholders  of record of LaSalle  Holdings,  LaSalle Re and
Trenwick  shall  not be deemed  shareholders  of record  until the  register  of
members of New Holdings is amended to reflect the allotment and issue of the New
Holdings Shares to such former shareholders.

     Section 2.11  Lost Certificates.  If any certificate representing Trenwick
Shares,  LaSalle Holdings Shares or Non-Voting Shares shall have been lost,
stolen or destroyed,  upon the making of an affidavit of that fact by the Person
claiming such  certificate  to be lost,  stolen or destroyed and, if required by
New Holdings,  the posting by such Person of a bond in such reasonable amount as
the New  Holdings  may direct as  indemnity  against  any claim that may be made
against it with  respect to such  certificate,  the Trenwick  Exchange  Agent or
LaSalle  Exchange  Agent,  as the case may be, will deliver in exchange for such
lost,  stolen or destroyed  certificate  the Trenwick  Consideration  or LaSalle
Consideration,  as the case may be, with respect to the Trenwick Shares, LaSalle
Holdings Shares or Non-Voting Shares formerly represented  thereby,  without any
interest thereon.



                                       15

<PAGE>


     Section 2.12  No  Fractional   Shares.  No  certificates  or  scrip
representing  fractional  New  Holdings  Shares  shall be  issued  upon the
conversion of Trenwick Shares,  LaSalle Holding Shares, or NonVoting Shares, but
in lieu thereof  each holder  otherwise  entitled to a  fractional  New Holdings
Share (after taking into account all Trenwick Shares, LaSalle Holdings Shares or
Non-Voting  Shares,  as  applicable,  owned by such holder) shall be entitled to
receive,  from the Trenwick  Exchange Agent or the LaSalle  Exchange  Agent,  as
applicable,  in  accordance  with the  provisions  of this Section  2.12, a cash
payment in lieu of such fractional New Holdings Share  representing the value of
such  fraction,  which for this purpose shall be  calculated by (i)  multiplying
such  fraction  by the  product of the Average  Closing  Price and the  Trenwick
Exchange Ratio in the case of Trenwick Shares and (ii) multiplying such fraction
by the product of the Average  Closing Price and the LaSalle  Exchange  Ratio in
the  case  of  LaSalle  Holdings  Shares  and  Non-Voting  Shares.  As  soon  as
practicable after the determination of the amount of cash, if any, to be paid to
holders of Trenwick Shares,  LaSalle Holdings Shares,  or Non-Voting  Shares, as
applicable,  in lieu of any fractional New Holdings Share, the Trenwick Exchange
Agent or the LaSalle  Exchange Agent, as applicable,  shall promptly pay without
interest  to all  holders  of  Trenwick  Shares,  LaSalle  Holdings  Shares,  or
Non-Voting Shares, as applicable,  entitled thereto all such amounts. Holders of
interests  representing  fractional New Holdings Shares shall not be entitled to
vote such interests or to any other rights as a shareholder of New Holdings.

                                    ARTICLE 3

                   REPRESENTATIONS AND WARRANTIES OF TRENWICK

         Trenwick hereby represents and warrants to LaSalle Holdings that:

         Section 3.1     Corporation; Organization.

         (a) Except as set forth in Section  3.1(a) of the  Trenwick  Disclosure
Letter,   each   of   Trenwick  and   its   Subsidiaries  is  a   company  duly
incorporated,   validly   existing  and  in  good  standing   (with  respect  to
jurisdictions that recognize such concept) under the laws of the jurisdiction of
its  incorporation.  Each of Trenwick  and its  Subsidiaries  (i) is  qualified,
licensed or domesticated  as a foreign  corporation in all  jurisdictions  where
such qualification,  license or domestication is required to own and operate its
properties  and conduct its  business in the manner and at the places  presently
conducted; (ii) holds all franchises, grants, licenses,  certificates,  permits,
consents and orders,  all of which are valid and in full force and effect,  from
all  applicable  regulatory   authorities  necessary  to  own  and  operate  its
properties and to conduct its business in the manner and at the places presently


                                       16

<PAGE>


conducted;  and (iii) has full power and authority (corporate and other) to own,
lease and  operate  its  respective  properties  and  assets and to carry on its
business as presently  conducted and as proposed to be  conducted,  except where
the  failure  to be so  qualified,  licensed  or  domesticated  or to hold  such
franchises, grants, licenses,  certificates,  permits, consents and orders or to
have such power and authority would not, when taken together with all other such
failures,  reasonably be expected to have a Material Adverse Effect on Trenwick.
Trenwick has furnished to LaSalle  Holdings  complete and correct  copies of its
certificate of incorporation  and by-laws as in effect on the date hereof.  Such
certificate  of  incorporation  and  by-laws are in full force and effect and no
other constitutional documents are applicable to or binding upon Trenwick.

         (b) Trenwick conducts its insurance and reinsurance  operations through
the Subsidiaries set forth in Section 3.1(b) of the Trenwick  Disclosure  Letter
(collectively,  the  "Trenwick  Insurance  Subsidiaries").  Each of the Trenwick
Insurance  Subsidiaries  is (i) duly  licensed  or  authorized  as an  insurance
company or (as applicable) a reinsurer in its  jurisdiction of  incorporation or
duly  licensed  to  operate  in  the  insurance  or  reinsurance   business  (as
applicable)  in  its  jurisdiction  of  incorporation,  (ii)  duly  licensed  or
authorized as an insurance company and (as applicable) a reinsurer in each other
jurisdiction  where it is  required  to be so  licensed  or  authorized  or duly
licensed to operate in the insurance or reinsurance  business (as applicable) in
each other  jurisdiction  where it is required to be so licensed  and (iii) duly
authorized  in its  jurisdiction  of  incorporation  and each  other  applicable
jurisdiction to write each line of business  currently  written by such Trenwick
Insurance  Subsidiaries,  except,  in any such case,  where the failure to be so
licensed or authorized is not reasonably  expected to have,  individually  or in
the aggregate,  a Material  Adverse  Effect on Trenwick.  Except as set forth in
Section 3.1(b) of the Trenwick Disclosure Letter, Trenwick has made all required
filings under  applicable  insurance  holding company  statutes except where the
failure to file is not reasonably  expected to have a Material Adverse Effect on
Trenwick.

         Section 3.2    Authority; Approval and Fairness.

         (a) Trenwick has all requisite corporate power and authority to execute
and deliver this Agreement and, subject to the due approval and adoption of this
Agreement  by  its  stockholders,  to  perform  its  obligations  hereunder  and
consummate  the  transactions  contemplated  hereby.  Trenwick has all requisite
corporate  power and authority to enter into the Stock Option  Agreements and to
consummate the transactions  contemplated thereby. The execution and delivery of
this  Agreement  by Trenwick,  the  performance  by Trenwick of its  obligations
hereunder  and the  consummation  by Trenwick of the  transactions  contemplated
hereby have been duly authorized by all necessary  corporate  action on the part
of Trenwick,  subject only to compliance with the provisions of Sections 264 and
271 of the GCL.  No other  corporate  proceedings  on the part of  Trenwick  are
necessary  for the  execution  and delivery of this  Agreement by Trenwick  and,
subject to  compliance  with the  provisions of Sections 264 and 271 of the GCL,
the performance by Trenwick of its obligations hereunder and the consummation by
Trenwick of the transactions  contemplated  hereby. This Agreement and the Stock
Option  Agreements  have  been duly  executed  and  delivered  by  Trenwick  and
(assuming the due  authorization,  execution and delivery of this  Agreement and
the Stock Option  Agreements by LaSalle  Holdings,  LaSalle Re),  subject to the
provisions  of  Section  264 and 271 of the GCL,  constitute  legal,  valid  and
binding obligations of Trenwick,  enforceable against Trenwick in accordance its
terms, subject with respect to enforceability to the effect of bankruptcy,



                                       17

<PAGE>



fraudulent conveyance,  insolvency,  reorganization,  moratorium or similar laws
now or hereafter affecting the enforcement of creditors' rights generally and to
the availability of equitable remedies.

         (b) The Board of Directors of Trenwick (the  "Trenwick  Board") (i) has
unanimously  (by all  directors  present  at a  meeting  duly  called  and held)
declared  that it  considers  this  Agreement,  the Plan of Merger and the other
transactions  contemplated  hereby to be advisable and in the best  interests of
Trenwick  and its  stockholders,  and (ii) has  authorized  and  approved in all
respects  this  Agreement,  the Plans and the  other  transactions  contemplated
hereby.

         Section 3.3    Capital Structure.

         (a) As of the date hereof,  the  authorized  capital  stock of Trenwick
consists  of  30,000,000  shares of common  stock  with a par value of $0.10 per
share and  2,000,000  shares of  preferred  stock  with a par value of $0.10 per
share.  As of December  15,  1999,  (i)  17,397,809  shares of common stock were
issued and  outstanding,  (ii) no shares of common  stock were held as  treasury
shares or by  Subsidiaries  of Trenwick,  (iv) 200,000 shares of Series B Junior
Participating  Preferred  Stock were  reserved for issuance upon exercise of the
rights  (the  "Rights")  distributed  to the  holders of shares of common  stock
pursuant to the Rights  Agreement  dated as of  September  24, 1997 (the "Rights
Agreement"),  between  Trenwick and First  Chicago Trust Company of New York, as
Rights Agent,  and (v) no shares of preferred  stock were issued or outstanding.
Section  3.3(a)  of  the  Trenwick  Disclosure  Letter  sets  forth  each  plan,
arrangement or agreement pursuant to which options or stock appreciation  rights
with  respect to Trenwick  Shares may be granted or under which such  options or
stock  appreciation  rights have been granted and are outstanding (the "Trenwick
Option  Plans") and in the  aggregate  the  maximum  number of options and stock
appreciation  rights  outstanding as of the date hereof and the class and number
of Trenwick  Shares  reserved for issue  pursuant to the  Trenwick  Option Plans
(such options and rights being herein collectively  referred to as the "Trenwick
Options"),  together  with a listing of the  aggregate  number of such  Trenwick
Options which shall vest at the Merger Effective Time as a result of the Plan of
Merger.  Each of the  outstanding  shares of capital stock of each Subsidiary of
Trenwick,  other  than  the  110,000  redeemable  preferred  capital  securities
(liquidation  amount $1,000 per security)  issued by Trenwick Capital Trust I, a
Delaware  statutory business trust ("Trenwick  Capital"),  and other than as set
forth in Section  3.3(a) of the  Trenwick  Disclosure  Letter,  is  directly  or
indirectly owned by Trenwick, free and clear of all Liens.

         (b) Except as  described in Section  3.3(b) of the Trenwick  Disclosure
Letter, no bonds,  debentures,  notes or other indebtedness  having the right to
vote (or  convertible  into or exercisable  for  securities  having the right to
vote) on any matters on which  stockholders may vote ("Voting Debt") of Trenwick
or any of its Subsidiaries are issued or outstanding.

         (c) Except as described in Sections 3.3(a),  (b) or (c) of the Trenwick
Disclosure  Letter,  there  are  no  options,   warrants,   calls,  rights,
commitments  or  agreements  of any  character  to which  Trenwick or any of its
Subsidiaries is a party or by which any of them is bound obligating  Trenwick or
any of its  Subsidiaries  to  issue,  deliver  or sell,  or cause to be  issued,
delivered  or sold,  additional  shares of capital  stock or any Voting  Debt of
Trenwick  or  any of  its  Subsidiaries  or  obligating  Trenwick  or any of its
Subsidiaries  to grant,  extend or enter into any such  option,  warrant,  call,
right,  commitment  or  agreement.  Except as set forth in this  Agreement or in
Section  3.3(c) of the  Trenwick  Disclosure  Letter,  there are no  outstanding
contractual  obligations of Trenwick or any of its  Subsidiaries  to repurchase,
redeem or  otherwise  acquire any shares of capital  stock of Trenwick or any of
its Subsidiaries.



                                       18
<PAGE>

         (d) Except as  described in Section  3.3(d) of the Trenwick  Disclosure
Letter or as  specifically  described in this Agreement and except for quarterly
dividends  in an amount not in excess of $0.26 per share,  since  September  30,
1999,  Trenwick  has not (i) made or  agreed  to make any  share  split or share
dividend, or issued or permitted or agreed to permit to be issued any shares, or
securities  exercisable  for or  convertible  into shares,  of capital  stock of
Trenwick  other than  pursuant to and as  required by the terms of any  Trenwick
Option;  (ii) repurchased,  redeemed or otherwise acquired any shares of capital
stock  of  Trenwick;  or  (iii)  declared,  set  aside,  made  or  paid  to  the
stockholders  of Trenwick  dividends or other  distributions  on the outstanding
shares of capital stock of Trenwick.

         Section 3.4   SEC Reports; Financial Statements.

         (a) Trenwick has delivered or made available to LaSalle Holdings a true
and  complete  copy  of  each  report,  schedule,   registration  statement  and
definitive proxy statement or information  statement  (including exhibits) filed
by Trenwick or Chartwell Re Corporation ("Chartwell") with the SEC in respect of
their  respective  fiscal  years  ending  December  31,  1997 and 1998 and their
respective  quarters ending after December 31, 1998 under the Securities Act and
the Exchange Act and will deliver to LaSalle  Holdings  promptly upon the filing
thereof with the SEC all such reports,  schedules,  registration  statements and
proxy statements  (including exhibits) as may be filed after the date hereof and
prior to the  Effective  Time (as such  documents  have  since the time of their
filing been amended,  including without limitation,  amendments reflected in the
Joint  Proxy  Statement/Prospectus  dated  September  7, 1999 or may after their
filing, if after the date hereof, be amended, the "Trenwick SEC Reports"), which
are or will be all the  documents  that Trenwick was or will be required to file
with the SEC.  Except as disclosed in Section 3.4(a) of the Trenwick  Disclosure
Letter,  as of their respective dates, the Trenwick SEC Reports complied or will
comply in all material  respects with the  requirements of the Securities Act or
the Exchange Act, as the case may be, and the rules and  regulations  of the SEC
thereunder  applicable to the Trenwick SEC Reports, and none of the Trenwick SEC
Reports  contained  or will contain any untrue  statement of a material  fact or
omitted or will omit to state a material fact  required to be stated  therein or
necessary to make the statements  therein,  in light of the circumstances  under
which they were made or will be made, not misleading.

         (b) As of their respective dates, the financial  statements of Trenwick
included or to be included in the Trenwick SEC Reports (the "Trenwick  Financial
Statements")  complied or will comply as to form in all material  respects  with
applicable accounting  requirements and with the published rules and regulations
of the SEC with respect  thereto,  and  presented or will present  fairly in all
material  respects  the  consolidated  financial  position of  Trenwick  and its
Subsidiaries   and  the   consolidated   results  of   operations,   changes  in
stockholders'  equity and cash flows of Trenwick and its  Subsidiaries as of the
dates and for the  periods  indicated,  in  accordance  with GAAP  applied  on a
consistent basis,  subject in the case of interim financial statements to normal
year-end  adjustments and except for the absence of certain footnote information
in the unaudited statements.



                                       19


<PAGE>


         (c)  Except as set forth in, or arising  out of facts or  circumstances
disclosed  in,  filings  by  Trenwick  with the SEC  prior  to the date  hereof,
Trenwick and its Subsidiaries have no liabilities,  debts, claims or obligations
of any nature on the date hereof, whether accrued, absolute, direct or indirect,
contingent or otherwise, whether due or to become due, that would be required to
be  included on a balance  sheet  prepared in  accordance  with GAAP  ("Trenwick
Liabilities"),  and there is no existing condition or set of circumstances which
would reasonably be expected to result in a Trenwick  Liability,  except for (i)
Trenwick  Liabilities  incurred in the ordinary and usual course of business and
consistent   with  past  practice  since   September  30,  1999,  (ii)  Trenwick
Liabilities  incurred  in  connection  with or as a result  of the  transactions
contemplated  by this  Agreement and (iii) Trenwick  Liabilities  that would not
reasonably be expected to have a Material Adverse Effect on Trenwick.

        Section 3.5   Absence of Certain Changes or Events. Except in connection
with this  Agreement,  the  Plans,  the  Stock  Option  Agreements  and the
transactions  contemplated  hereby and thereby or except as described in Section
3.5 of the Trenwick  Disclosure Letter, as disclosed in the Trenwick SEC Reports
filed and publicly  available  prior to the date of this  Agreement  (the "Filed
Trenwick  SEC  Reports")  since the date of the most  recent  audited  financial
statements  included  in the  Filed  Trenwick  SEC  Reports,  Trenwick  and  its
Subsidiaries  have conducted  their business in the ordinary  course  consistent
with past  practice,  and there has not occurred (i) any event or change  having
individually or in the aggregate a Material Adverse Effect on Trenwick, (ii) any
declaration,  setting  aside or payment of any  dividend  or other  distribution
(whether  in  cash,  stock  or  property)  with  respect  to any  of  Trenwick's
outstanding  capital stock,  other than regular  quarterly cash dividends of not
more than $0.26 per share on the Trenwick  Shares and  dividends  paid by wholly
owned  subsidiaries,   (iii)  (A)  any  granting  by  Trenwick  or  any  of  its
Subsidiaries  to any  current or former  director  or officer of Trenwick or its
Subsidiaries of any increase in  compensation,  bonus or other benefits,  except
for normal  increases  in the ordinary  course of business,  (B) any granting by
Trenwick or any of its  Subsidiaries  to any such current or former  director or
officer of any  increase in  severance  or  termination  pay or (C) any entry by
Trenwick or any of its Subsidiaries  into, or any amendments of, any employment,
deferred  compensation,  consulting,  severance,  termination or indemnification
agreement  with any such  current or former  director or  officer,  (iv) any tax
election that  individually  or in the aggregate  would have a Material  Adverse
Effect on Trenwick or any of its tax  attributes or any settlement or compromise
of any material income tax liability,  or (v) any change in accounting  methods,
principles  or  practices  by  Trenwick  or any of its  Subsidiaries  materially
affecting their assets, liabilities or business, except insofar as may have been
required or permitted by a change in applicable accounting principles (including
statutory accounting practices ("SAP")).

     Section 3.6   Certain Fees. No finder, broker, agent, financial advisor or
other  intermediary  other  than DLJ has  acted on behalf  of  Trenwick  in
connection with this Agreement or the transactions  contemplated  hereby,  or is
entitled to any payment in connection herewith. Trenwick has provided to LaSalle
Holdings copies of Trenwick's engagement letter with DLJ in connection with this
Agreement and the transactions contemplated hereby.



                                       20

<PAGE>

     Section 3.7   No  Defaults.  Neither  Trenwick nor any of its Subsidiaries
is in default or violation  (and no event has occurred which with notice or
lapse  of  time  or  both  would  constitute  a  default  or  violation)  of its
certificate of  incorporation  or by-laws or other  governing  document,  or any
material agreement,  mortgage,  indenture,  debenture,  trust, lease, license or
other  instrument or  obligation  to or by which it or any of its  properties is
subject or bound (the  "Trenwick  Instruments"),  except  for such  defaults  or
violations as would not reasonably be expected to have,  individually  or in the
aggregate, a Material Adverse Effect on Trenwick. Except as set forth in Section
3.7 of the Trenwick  Disclosure Letter, the execution,  delivery and performance
of this  Agreement  and the  taking of any  other  action  contemplated  by this
Agreement  will not (i) result in any  violation  of or be in  conflict  with or
constitute a breach or default (with or without notice or lapse of time or both)
under (a) the  certificate  of  incorporation  or  by-laws  of  Trenwick  or its
Subsidiaries or (b) any of the other Trenwick  Instruments,  except for any such
violation  of,  conflict  with,  breach  of or  default  under  which  would not
reasonably be expected to have,  individually  or in the  aggregate,  a Material
Adverse Effect on Trenwick,  (ii) result in or constitute an event entitling any
party to a Trenwick  Instrument to effect an acceleration of the maturity of any
indebtedness  of Trenwick or any of its  Subsidiaries or an increase in the rate
of interest  presently in effect with respect to such  indebtedness,  except for
any such  accelerations  or increases  which would not reasonably be expected to
have, individually or in the aggregate, a Material Adverse Effect on Trenwick or
(iii) result in the creation of any Lien upon any of the properties or assets of
Trenwick, except for Permitted Liens and any Liens which would not reasonably be
expected to have, individually or in the aggregate, a Material Adverse Effect on
Trenwick.

         Section 3.8    Consents.

         (a)  Except as set forth in Section 3.8 of the Trenwick Disclosure
Letter and except for  compliance  with the  provisions of Sections 264 and
271 of the GCL and the  approval of  Lloyd's,  no  consent,  approval,  order or
authorization of, or registration,  qualification,  designation,  declaration or
filing with, any Governmental  Authority  ("Consent") is required on the part of
Trenwick or any of its  Subsidiaries in connection with the execution,  delivery
and  performance by Trenwick of this Agreement and the  consummation by Trenwick
of the transactions contemplated hereby, except those required by (i) compliance
with any applicable requirements of the Hart-Scott-Rodino Antitrust Improvements
Act of 1976, as amended (the "HSR Act"),  (ii) United  States  federal and state
securities  or "Blue Sky" laws and (iii) where  failure to obtain  such  Consent
would not be reasonably expected to have a Material Adverse Effect on Trenwick.

         (b) Other than the affirmative  vote of the holders of more than 50% of
the issued  and  outstanding  Trenwick  Shares  (with each share having one vote
per share) required to approve and adopt this Agreement,  the Plan of Merger and
the Plan of  Reorganization,  there is no other vote, consent or approval of the
holders  of  any  class  of  shares  of Trenwick  necessary to approve and adopt




                                       21
<PAGE>


this Agreement, the Plan of Merger, the Plan of Reorganization and the
transactions contemplated hereby.

     Section 3.9  Compliance   with   Applicable  Law.  Each  of  Trenwick  and
its  Subsidiaries  is in compliance  with all  licenses,  permits and other
authorizations,  domestic  or  foreign,  necessary  to  conduct  its  respective
business, except where failure to have or comply with such licenses, permits and
authorizations would not reasonably be expected to have,  individually or in the
aggregate,  a Material  Adverse Effect on Trenwick.  Neither Trenwick nor any of
its  Subsidiaries  is in default or violation  (and no event has occurred  which
with  notice  or the  lapse  of time or  both  would  constitute  a  default  or
violation) of any judgment,  decree,  order, law, statute, rule or regulation of
any Governmental Authority,  except for such defaults or violations as would not
reasonably be expected to have,  individually  or in the  aggregate,  a Material
Adverse  Effect on Trenwick.  Subject to obtaining  the Consents  referred to in
Section  3.8,  the  execution,  delivery and  performance  of this  Agreement by
Trenwick  and the  consummation  by  Trenwick of the  transactions  contemplated
hereby prior to the date or dates as of which the representations and warranties
herein are made or deemed  made,  will not result in any default or violation of
any  judgment,   decree,   order,  law,  statute,  rule  or  regulation  of  any
Governmental  Authority  applicable to Trenwick or its Subsidiaries,  except for
such  defaults  or  violations  as would not  reasonably  be  expected  to have,
individually or in the aggregate, a Material Adverse Effect on Trenwick.

     Section 3.10  Information  Supplied.  None of the  information  supplied or
to be supplied by Trenwick for inclusion or  incorporation  by reference in
the Registration Statement on Form S-4 (the "Form S-4") to be filed with the SEC
by  New  Holdings  relating  to  the  New  Holdings  Shares  comprising  LaSalle
Consideration and Trenwick Consideration will, at the time the Form S-4 is filed
with  the SEC,  at any  time it is  amended  or  supplemented  or at the time it
becomes  effective under the Securities Act,  contain any untrue  statement of a
material fact or omit to state any material  fact required to be stated  therein
or necessary to make the statements therein, in light of the circumstances under
which such statements were made, not  misleading.  The letters to  shareholders,
notices of meetings,  proxy statements and forms of proxies to be distributed to
shareholders of LaSalle Holdings and stockholders of Trenwick,  respectively, in
connection  with the  Plans and the  transactions  contemplated  hereby,  except
information  supplied by LaSalle  Holdings in writing for inclusion in the Joint
Proxy  Statement (as defined  herein),  will not, as of the date the Joint Proxy
Statement is first mailed to such  shareholders  and on the date of the meetings
of Trenwick's  stockholders or LaSalle Holdings'  shareholders,  as the case may
be, and the date of any postponement or adjournment thereof,  contain any untrue
statement of a material  fact or omit to state any material  fact required to be
stated therein or necessary in order to make the statements therein, in light of
the  circumstances  under which they were made, not misleading.  The information
and documents  referred to in the previous two sentences are herein  referred to
as the "Joint Proxy  Statement."  All documents that Trenwick is responsible for
filing with any  Governmental  Authority  in  connection  with the  transactions
contemplated  hereby will comply as to form in all  material  respects  with the
provisions of any applicable law.




                                       22

<PAGE>

     Section 3.11.   Material  Contracts. Except  as set forth in  Section  3.11
of the Trenwick Disclosure Letter:

         (a)  All of the  contracts of Trenwick  and its  Subsidiaries  that are
required to be  described in the Trenwick SEC Reports or to be filed as exhibits
thereto (including, without limitation, contracts of Chartwell) are described in
the Trenwick SEC Reports or filed as exhibits  thereto and are in full force and
effect.

         (b)  Neither  Trenwick  nor any of its  Subsidiaries  is a party to any
agreement  containing any provision or covenant limiting in any material respect
the ability of Trenwick or any of its  Subsidiaries  (or New  Holdings or any of
its  Subsidiaries  subsequent to the Effective Time) to (i) sell any products or
services of or to any other  Person,  (ii) engage in any line of business in any
geographical  area or (iii) compete with or to obtain  products or services from
any Person or limiting the ability of any Person to provide products or services
to Trenwick or any of its Subsidiaries.

         (c)  Neither  Trenwick  nor any of its  Subsidiaries  is a party to or
bound by any contract,  agreement or arrangement which would cause the rights or
obligations of any party thereto to change in the event of the Plans, except for
any such  contract,  agreement  or  arrangement  which would not  reasonably  be
expected to have, individually or in the aggregate, a Material Adverse Effect on
Trenwick.

     Section 3.12 Taxes.   Except as provided in Section 3.12 of the Trenwick
Disclosure Letter:

         (a) Trenwick and its Subsidiaries have filed or caused to be filed with
the  appropriate  United  States  federal,   state,  local,  foreign  and  other
Governmental  Authorities,  all Tax  returns,  information  returns  and reports
required to be filed on or prior to the date  hereof  (taking  into  account all
valid  extensions).  All such Tax returns,  information  returns and reports are
complete and accurate in all material respects.

         (b) Trenwick and its  Subsidiaries  have paid in full or made  adequate
provision (in accordance with GAAP) for the payment of all Taxes shown to be due
on the  Tax  returns  referred  to in  Section  3.12(a).  All  material  written
assessments  of Taxes due and  payable by or on behalf of Trenwick or any of its
Subsidiaries  have either been paid or provided for (in accordance with GAAP) or
are being contested in good faith by appropriate proceedings.

         (c) There are no material Tax claims pending against Trenwick or any of
its  Subsidiaries  and Trenwick  does not know of any  threatened  claim for Tax
deficiencies  or any basis for such claims,  no material issues have been raised
in any  examination  by any taxing  authority with respect to Trenwick or any of
its Subsidiaries which, by application of similar  principles,  reasonably could
be  expected  to result in a  proposed  deficiency  for any other  period not so
examined,  and there are not now in force any waivers or  agreements by Trenwick
or any of its  Subsidiaries  for the extension of time for the assessment of any
material Tax, nor has any such waiver or agreement  been requested by any taxing
authority.  Neither  Trenwick nor any of its  Subsidiaries has any liability for
any material United States federal,  state, local, foreign or other Taxes of any
corporation or entity other than Trenwick and its Subsidiaries.



                                       23

<PAGE>


         (d) There  are  no  Liens on any of the  assets   of Trenwick or any of
its   Subsidiaries   that  arose in   connection   with any  failure (or alleged
failure)  to pay any Taxes  (other  than  Taxes  that are not due as of the date
hereof).

         (e) Trenwick  and its  Subsidiaries  have  withheld and paid all United
States  federal,  state,  local,  foreign and other Taxes  required to have been
withheld and paid in  connection  with  amounts  paid or owing to any  employee,
independent contractor, creditor, stockholder or other third party.

         (f) To Trenwick's knowledge, Section 3.12(f) of the Trenwick Disclosure
Letter  discloses,  with respect to the year ended December 31, 1998 and for the
period  commencing  January  1,  1999 and  ending  on the  date of the  Trenwick
Disclosure Letter, (i) each insurance or reinsurance  transaction by Trenwick or
any of its  Subsidiaries  directly with  stockholders  of Trenwick and (ii) each
insurance  or  reinsurance  transaction  by Trenwick or any of its  Subsidiaries
directly or indirectly  with Persons related to stockholders of Trenwick and not
disclosed  in  clause  (i)  above,  which  would  cause  Trenwick  or any of its
Subsidiaries to have any "related person insurance income" within the meaning of
Section 953(c)(2) of the Code.

         (g) To Trenwick's knowledge, Trenwick and its Subsidiaries did not have
for the year ended December 31, 1998,  and Trenwick does not expect  Trenwick or
any of its  Subsidiaries  to have for the period ending at the Merger  Effective
Time  (treating  such  period as if it were a  taxable  year),  "related  person
insurance  income" within the meaning of Section 953(c)(2) of the Code in excess
of the exceptions provided in Sections 953(c)(3)(A) and (B) of the Code.

         (h) To Trenwick's knowledge,  except as disclosed in Section 3.12(h) of
the Trenwick Disclosure Letter, neither Trenwick nor any of its Subsidiaries is,
nor has Trenwick or any of its  Subsidiaries  ever been, a  "controlled  foreign
corporation" within the meaning of Section 957(a) or 957(b) of the Code.

         (i) A  representation  with respect to Taxes  contained in this Section
3.12 shall be deemed to be accurate unless an inaccuracy contained therein would
reasonably be expected to have,  individually  or in the  aggregate,  a Material
Adverse Effect on Trenwick.

     Section 3.13   Litigation.  Except as disclosed in the Trenwick SEC Reports
filed  prior  to the  date  hereof  or in  Section  3.13  of  the  Trenwick
Disclosure  Letter,  there  are  no  actions,  suits,  claims,   proceedings  or
investigations  pending  against or, to the  knowledge of  Trenwick,  threatened
against  or  affecting,  Trenwick  or any of its  Subsidiaries  or any of  their
respective  properties or any syndicates  managed by a Lloyd's or other managing
agency which is a Subsidiary of Trenwick ("Trenwick Managing Agency") before any
Governmental  Authority  or  otherwise  which  (a)  would be  expected  to have,
individually or in the aggregate,  a Material Adverse Effect on Trenwick, (b) in
any  manner  challenges  or  seeks  to  prevent,  enjoin,  alter  or  delay  the
transactions  contemplated hereby or (c) alleges criminal action or inaction. As
of the  date  hereof,  neither  Trenwick  nor its  Subsidiaries  or any of their
respective  properties  is  subject to any order,  writ,  judgment,  injunction,
decree,  determination or award having, or which would reasonably be expected to
have, a Material  Adverse Effect on Trenwick or which would prevent or delay the
consummation of the transactions contemplated hereby. Except as disclosed in the




                                       24
<PAGE>



Trenwick SEC reports  filed  prior  to the date  hereof,  there  are no  pending
or,  to the knowledge of Trenwick,  threatened    claims for indemnification by
Trenwick or any of its  Subsidiaries in favor of directors, officers, employees
and agents of Trenwick or any of its Subsidiaries.

     Section 3.14   Title to Properties;  Leases. Except as set forth in
Section 3.14(a) of the Trenwick Disclosure Letter, each of Trenwick and its
Subsidiaries  has good and  marketable  title to, and is the lawful owner of, or
has the right to use pursuant to a license or otherwise, all of the tangible and
intangible assets, properties and rights used in its businesses and all tangible
and intangible  assets,  properties and rights reflected on the balance sheet of
Trenwick dated September 30, 1999 or acquired since September 30, 1999, free and
clear of all Liens (other than Permitted Liens) and material  defects.  Trenwick
and its  Subsidiaries  own no real  property.  Section  3.14(b) of the  Trenwick
Disclosure  Letter sets forth all material real  property and personal  property
leases of Trenwick and its Subsidiaries.  All such leases are valid, binding and
enforceable  against  Trenwick or its  Subsidiaries  (and,  to the  knowledge of
Trenwick and its  Subsidiaries,  each other party  thereto) in  accordance  with
their  respective  terms,  and  there  does not  exist,  under any lease of real
property or personal  property,  any material  defect or any event  which,  with
notice or lapse of time or both,  would  constitute  a  material  default by the
Trenwick  or its  Subsidiaries,  as the case may be,  or,  to the  knowledge  of
Trenwick and its Subsidiaries, by any other party thereto.

         Section 3.15   Employees.

         (a) Section  3.15(a)  of  the  Trenwick  Disclosure  Letter  lists  all
employment  contracts and similar  arrangements  between  Trenwick or any of its
Subsidiaries  and  their  respective   executive  officers  and  all  plans  and
arrangements  pursuant to which Trenwick or any of its Subsidiaries is obligated
to make any payment or confer any material  benefit upon any officer,  director,
employee or agent of Trenwick  or any of its  Subsidiaries  as a result of or in
connection  with any of the  transactions  contemplated by this Agreement or any
transaction or transactions  resulting in a change of control of Trenwick or any
of its  Subsidiaries  (including as a result of a  termination  of employment in
connection  with any of such events).  Except as described in Section 3.15(a) of
the Trenwick Disclosure Letter and except as would not reasonably be expected to
have a Material  Adverse Effect on Trenwick,  (a) Trenwick and its  Subsidiaries
have  complied  with all laws  relating to the  employment  of labor,  including
provisions  thereof relating to wages,  hours,  equal opportunity and collective
bargaining  and (b) no labor  dispute  with  employees of Trenwick or any of its
Subsidiaries  exists  or, to the  knowledge  of  Trenwick,  is  threatened.  The
severance  costs  associated  with the  acquisition  of  Chartwell  and  related
workforce  reductions  have  been  identified  and are as set  forth in  Section
3.15(a) of the Trenwick Disclosure Letter.



                                       25

<PAGE>


         (b) Except as set forth in Section  3.15(b) of the Trenwick  Disclosure
Letter,  neither  Trenwick  nor  any  of  its  Subsidiaries  is a  party  to any
collective  bargaining  or other  labor  union  contract  applicable  to Persons
employed  by  Trenwick  or any of its  Subsidiaries,  no  collective  bargaining
agreement  is  being  negotiated  by  Trenwick  or any of its  Subsidiaries  and
Trenwick has no knowledge of any activities or proceedings of any labor union to
organize any of their respective employees. There is no labor dispute, strike or
work  stoppage  against  Trenwick  or any of its  Subsidiaries  pending  or,  to
Trenwick's  knowledge,  threatened  which  may  interfere  with  the  respective
business  activities of Trenwick or any of its  Subsidiaries,  except where such
dispute, strike or work  stoppage  would not  reasonably  be expected to have a
Material Adverse Effect on Trenwick.

         (c) Trenwick has made all necessary  notifications to and received all
necessary  consents  from  Lloyd's and the  Financial  Services  Authority  with
respect to the employment of personnel requiring such notification or consents.

         Section 3.16    Benefit Plans.

         (a) (i) Each Employee  Benefit Plan  maintained or  contributed  to, or
required  to be  maintained  or  contributed  to,  by  Trenwick  or  any  of its
Subsidiaries for the benefit of any present or former U.S. officer,  employee or
director of Trenwick or any of its Subsidiaries (all the foregoing  collectively
referred to  hereinafter  as  "Trenwick  Benefit  Plans") has been  administered
substantially  in accordance  with its terms and any related trust  agreement or
insurance  contract has been  administered  substantially in accordance with its
terms.  Trenwick,  its  Subsidiaries and all the Trenwick Benefit Plans, and any
related trust agreements or insurance contracts,  are in substantial  compliance
with the applicable provisions of ERISA, the Code, all other applicable laws and
all applicable collective bargaining agreements.

                  (ii)  None of  Trenwick  or any other  person  or entity  that
                  together with Trenwick is treated as a single  employer  under
                  Section 414 of the Code (each a "Trenwick Commonly  Controlled
                  Entity") has incurred any material liability under Title IV of
                  ERISA  (other  than for the  payment of benefits or the timely
                  payment  of Pension  Benefit  Guaranty  Corporation  insurance
                  premiums,  in either  case in the  ordinary  course)  or under
                  Section 412(f) or 412(n) of the Code, and no condition  exists
                  which  could  reasonably  be  expected  to  present  a risk of
                  Trenwick or any Commonly  Controlled  Entity  incurring such a
                  material liability.

                  (iii) Neither  Trenwick nor any Trenwick  Commonly  Controlled
                  Entity is obligated to contribute to any "multiemployer  plan"
                  (as defined in Section  3(37) or Section  4001(a)(3) of ERISA)
                  or has any material liability,  including current or potential
                  withdrawal  liability  (within the meaning of Section  4201 of
                  ERISA) with respect to any multiemployer plan.

                  (iv) Except as  contemplated by Section 2.4 or as disclosed in
                  the Filed Trenwick SEC Documents or in Section  3.16(a)(iv) of
                  the Trenwick Disclosure  Schedule,  since the date of the most
                  recent  audited  financial  statements  included  in the Filed
                  Trenwick  SEC  Documents,  there has not been any  adoption or
                  amendment  by  Trenwick  or  any of  its  Subsidiaries  of any
                  collective  bargaining agreement or any Trenwick Benefit Plan.
                  Except as disclosed in the Filed  Trenwick SEC Documents or in
                  Section 3.16(a)(iv) of the Trenwick Disclosure Schedule, there
                  exist no employment, consulting, change in control, severance,
                  termination or  indemnification  agreements,  arrangements  or
                  understandings  between  Trenwick  or any  Subsidiary  and any
                  current or former employee, officer or director of Trenwick or
                  any Subsidiary or any Trenwick Benefit Plan.




                                       26

<PAGE>



                  (v) All material  contributions and other payments required to
                  be  made by  Trenwick  and its  subsidiaries  to any  Trenwick
                  Benefit  Plan prior to the date  hereof have been made and all
                  accruals  required to be made under any Trenwick  Benefit Plan
                  have been made. There is no claim, dispute, grievance, charge,
                  complaint,  restraining  or  injunctive  order,  litigation or
                  proceeding   pending,   or,  to  the  knowledge  of  Trenwick,
                  threatened  or  anticipated  (other  than  routine  claims for
                  benefits)  against or relating to any Trenwick Benefit Plan or
                  against the assets of any  Trenwick  Benefit  Plan which could
                  reasonably  be  expected  to result in the  imposition  of any
                  material  liability of Trenwick.  Neither  Trenwick nor any of
                  its Subsidiaries  has  communicated  generally to employees or
                  specifically to any employee  regarding any future increase of
                  benefit  levels (or future  creations  of new  benefits)  with
                  respect to any Trenwick Benefit Plans.

                  (vi) Each Trenwick Benefit Plan can be terminated or otherwise
                  discontinued   without  any   liability  to  Trenwick  or  any
                  subsidiary  that  would  reasonably  be  expected  to  have  a
                  Material Adverse Effect. With respect to each Trenwick Benefit
                  Plan  subject  to Title IV of ERISA and with  respect  to each
                  plan of a Trenwick Commonly Controlled Entity subject to Title
                  IV of ERISA (each a "Trenwick  Defined Benefit Plan") Trenwick
                  Defined  Benefit  Plan  (i) no  termination  of  any  Trenwick
                  Defined  Benefit  Plan has  occurred  pursuant  to  which  all
                  liabilities  have not been satisfied in full, and no event has
                  occurred  and no  condition  exists that could  reasonably  be
                  expected  to  result  in  Trenwick  or any  Trenwick  Commonly
                  Controlled Entity incurring  liability under Title IV of ERISA
                  or could  constitute  grounds  for  terminating  any  Trenwick
                  Defined Benefit Plan; (ii) each Trenwick  Defined Benefit Plan
                  which is subject  to Part 3 of  Subtitle B of Title I of ERISA
                  or Section 412 of the Code, has been  maintained in compliance
                  with the minimum  funding  standards of ERISA and the Code and
                  no  such  Trenwick  Defined  Benefit  Plan  has  incurred  any
                  "accumulated funding deficiency," as defined in Section 412 of
                  the Code and  Section  302 of ERISA,  whether  or not  waived;
                  (iii) neither  Trenwick nor any Trenwick  Commonly  Controlled
                  Entity  has  sought  or  received  a  waiver  of  its  funding
                  requirements with respect to any Trenwick Defined Benefit Plan
                  and all  material  contributions  payable with respect to each
                  Defined Benefit Plan have been timely made; (iv) no reportable
                  event,  within the  meaning of Section  4043 of ERISA,  and no
                  event described in Section 4062 or 4063 of ERISA, has occurred
                  with respect to any Trenwick  Defined  Benefit  Plan;  (v) the
                  aggregate  accumulated  benefit  obligations  of each Trenwick
                  Defined  Benefit  Plan subject to Title IV of ERISA (as of the
                  date of the most recent actuarial  valuation prepared for such
                  Trenwick  Defined  Benefit Plan) do not exceed the fair market
                  value of the assets of such Trenwick  Defined Benefit Plan (as
                  of the date of such valuation); and (vi) no amendment has been
                  made to any Trenwick Defined Benefit Plan that has required or
                  would  require the  provision of security  under ERISA Section
                  307 or Code Section 401(a)(29).



                                       27

<PAGE>

                  (vii)  The  execution,   delivery  and   performance  of  this
                  Agreement and the transactions contemplated hereby will not in
                  and of themselves result in the imposition of any federal
                  excise tax with respect to any Trenwick Benefit Plan.

                  (viii)  Neither  Trenwick  nor  any  subsidiary  maintains  or
                  contributes (or has maintained or contributed to) any Trenwick
                  Benefit  Plan which  provides,  or has a liability to provide,
                  life insurance,  medical, severance, or other employee welfare
                  benefits to any employee upon his retirement or termination of
                  employment,  except as may be required by Section 4980B of the
                  Code.

                  (ix) Neither Trenwick nor any of its subsidiaries maintains or
                  contributes to a trust,  organization or association described
                  in any of the Sections  501(c)(9),  501(c)(17) or 501(c)(2) of
                  the Code.

                  (x)  Favorable  determination  letters have been received from
                  the Internal  Revenue  Service  with respect to each  Trenwick
                  Benefit  Plan which is intended to comply with the  provisions
                  of Section 401(a) of the Code, and each such Trenwick  Benefit
                  Plan  complies  in  form  and in  operation  in  all  material
                  respects  with the  requirements  of a "qualified  plan" under
                  Section 401(a) of the Code.

                  (xi) Neither Trenwick nor any of its Subsidiaries,  nor any of
                  their  respective  directors,  officers,  employees or, to the
                  knowledge of Trenwick any other  "fiduciary,"  as such term is
                  defined  in  Section  3(21) of ERISA,  has any  liability  for
                  failure  to comply  with  ERISA or the Code for any  action or
                  failure  to act  in  connection  with  the  administration  or
                  investment of the Trenwick Benefit Plans.

                  (xii)  There has been no act or acts which  would  result in a
                  disallowance  of a  deduction  or  the  imposition  of  a  tax
                  pursuant  to  Section  4980B,  or with  regard  to plan  years
                  beginning before December 31, 1988, Section 162(i) of the Code
                  as in  effect  immediately  prior  to  the  enactment  of  the
                  Technical  and  Miscellaneous  Revenue  Act  of  1988,  or any
                  regulations promulgated  thereunder,  whether final, temporary
                  or  proposed.  No event has  occurred  with  respect  to which
                  Trenwick or any of its subsidiaries  could be liable for a tax
                  imposed  by Chapter  43 of  Subtitle  A of the Code,  or for a
                  civil  penalty  or other  liability  under  Section  502(c) or
                  Section 501(l) of ERISA.  Each Trenwick Benefit Plan that is a
                  "group  health  plan"  as  defined  in  Section  607 of  ERISA
                  complies in all  material  respects  and has been  operated in
                  substantial compliance in all respects with Part 7 of Title I,
                  Subtitle B of ERISA and Subtitle K of the Code.



                                       28

<PAGE>

                  (xiii) With  respect to each of the  Trenwick  Benefit  Plans,
                  Trenwick has  delivered to LaSalle  Holdings true and complete
                  copies of: (a) the plan documents, including any related trust
                  agreements, insurance contracts or other funding arrangements,
                  or a written  summary of the terms and  conditions of the plan
                  if there is no  written  plan  document;  (b) the most  recent
                  determination   letter  received  from  the  Internal  Revenue
                  Service;  (c) the  most  recent  IRS Form  5500;  (d) the most
                  recent  actuarial  valuation;  (e) the most  recent  financial
                  statement;  (f) all material  correspondence with the Internal
                  Revenue Service, the Department of Labor and the Pension
                  Benefit  Guaranty  Corporation with respect to the past three
                  plan years  other than IRS Form 5500 filings and PBGC premium
                  payments;  and (g) the most recent  summary plan description.

                  (xiv)  None  of the  payments  contemplated  by  any  Trenwick
                  Employee  Benefit Plans would,  in the  aggregate,  constitute
                  excess  parachute  payments (as defined in Section 280G of the
                  Code (without regard to subsection (b)(4) thereof)).

                  (xv) Except as  disclosed  in the Section  3.16(a)(xv)  of the
                  Trenwick  Disclosure  Letter,  the consummation of the Plan of
                  Merger (or the  approval  thereof by the  parties'  respective
                  shareholders) and the other transactions  contemplated by this
                  Agreement,  will not (x) entitle any employees or directors of
                  Trenwick  or  of  any  Trenwick  Commonly  Controlled  Entity,
                  directly or indirectly to severance  pay; (y)  accelerate  the
                  time  of  payment  or  vesting  or  trigger   any  payment  of
                  compensation or benefits under, or increase the amount payable
                  or trigger any other material  obligation  pursuant to, any of
                  the  Trenwick  Benefit  Plans;  or (z) result in any breach or
                  violation  of, or default  under any of the  Trenwick  Benefit
                  Plans.

         (b) Except as would not have a  Material  Adverse  Effect on  Trenwick,
except as set forth in Section 3.16(b) of the Trenwick  Disclosure Letter and so
far as Pierre D. Croizat,  Russell J. English,  Andrew Okell and Joanne Merrick,
who are senior management of Trenwick's international operations, are aware:

                  (i) There is no existing or threatened  or pending  industrial
                  or trade  dispute  involving  Trenwick  International  Limited
                  ("Trenwick   International")  and  any  of  the  employees  of
                  Trenwick  International  and there are no facts known or which
                  would on reasonable inquiry be known to Trenwick International
                  which  might  indicate  that  there  may be any  such  dispute
                  (excluding  the Merger and the  transactions  contemplated  by
                  this  Agreement).  There  are no  agreements  or  arrangements
                  (whether  oral or in writing or  existing  by reason of custom
                  and  practice  and  whether or not  legally  binding)  between
                  Trenwick International and any trade union or other employees'
                  representatives  or  organization  concerning or affecting the
                  employees  of  Trenwick  International  and there are no trade
                  unions  or  other  employees'  representatives  whom  Trenwick
                  International   recognizes   to  any  extent  for   collective
                  bargaining  purposes nor, so far as Trenwick  International is
                  aware, has Trenwick  International done any act which might be
                  construed as recognition.



                                       29

<PAGE>


                  (ii)  Trenwick  International  has  given  no  notice  of  any
                  redundancies  to the  U.K.  Secretary  of  State  nor  started
                  consultations  with any independent  trade union or employees'
                  representatives  within  the  preceding  period of one year in
                  relation  to  any  employees  of  Trenwick  International.  No
                  circumstances  have arisen under which Trenwick  International
                  is likely to be required to pay damages for wrongful dismissal
                  or breach of contract,  to make any  contractual  or statutory
                  redundancy  payment or make or pay any compensation in respect
                  of unfair  dismissal, to make  any   other  payment under any
                  employment  protection    legislation or  to  reinstate  or
                  re-engage  any  former   employee.   No  circumstances  have
                  arisen under  which Trenwick  International  is likely to be
                  required to pay  damages or  compensation,  or  suffer  any
                  penalty  or  be  required to  take   corrective  action  or
                  be  subject  to any form of  discipline  under the  Employment
                  Rights  Act  1996,   the  Trade  Union  and  Labor   Relations
                  (Consolidation)   Act  1992,  the  Transfer  of   Undertakings
                  (Protection   of   Employment)   Regulations   1981,  the  Sex
                  Discrimination Act 1975, the Equal Pay Act 1970, the Treaty of
                  Rome or any Directive or  recommendation  made pursuant to it,
                  the Race Relations Act 1976 or the  Disability  Discrimination
                  Act 1995. So far as Trenwick International is aware, there are
                  no current,  pending or threatened  claims of any type against
                  Trenwick  International by any existing or former employees or
                  directors  of  Trenwick  International  or by any  existing or
                  former consultants to Trenwick International.

                  (iii) There are no  existing  service or other  agreements  or
                  contracts  between  Trenwick  International  and  any  of  its
                  directors or executives or employees  which cannot be lawfully
                  terminated  by six  calendar  months'  notice or less  without
                  giving  rise to any claim for  damages or  compensation  other
                  than a  statutory  redundancy  payment  or a claim for  unfair
                  dismissal  depending on the  circumstances of the termination.
                  Trenwick  International  has  complied  with all its  material
                  obligations  under  all  legislation,  regulations  and  other
                  requirements  having  the  force  of law  (including,  without
                  limitation,   orders  and  awards)  in  connection   with  its
                  employees, directors and consultants.

                  (iv) Trenwick  International  is not involved in  negotiations
                  (whether with employees or any trade union or other employees'
                  representatives)   to  vary  the  terms  and   conditions   of
                  employment or engagement of any of its employees, directors or
                  consultants  and has not made any  representations,  promises,
                  offers or  proposals  to any of its  employees,  directors  or
                  consultants  or  to  any  trade  union  or  other   employees'
                  representatives   concerning   or  affecting   the  terms  and
                  conditions   of   employment  or  engagement  of  any  of  its
                  employees, directors or consultants.




                                       30

<PAGE>

                  (v) Trenwick  International  has discharged its obligations in
                  full in relation to salary, wages, fees, commission,  bonuses,
                  overtime pay, holiday pay, sick pay and all other benefits and
                  emoluments   relating  to  its  employees,   consultants   and
                  directors in respect of all prior periods.

                  (vi) There are no pension, share option, share incentive, life
                  assurance,  disability  or similar  schemes,  arrangements  or
                  obligations   for  any  employees  or  directors  of  Trenwick
                  International,  and Trenwick  International has no obligations
                  (whether  legally binding or established by custom) to pay any
                  pension or make any other payment after retirement or death or
                  otherwise to provide "relevant benefits" within the meaning of
                  Section 612 of the U.K. Income and Corporation  Taxes Act 1988
                  or to make any  payment  for the  purpose  of  providing  such
                  "relevant  benefits" to or in respect of any person who is now
                  or has been an officer or employee of  Trenwick  International
                  and is not  a party to  any  scheme  or arrangement  having as
                  its purpose or one of its purposes the making of such payments
                  or the provision of such benefits.

                  (vii) All Employee  Benefit  Plans comply with and have at all
                  times complied with the provisions of the relevant legislation
                  and the  requirements  of the Pension  Schemes  Office and the
                  Contributions  Agency affecting schemes approved under Chapter
                  I of Part XIV of the U.K.  Income  and  Corporation  Taxes Act
                  1988. Trenwick  International and the trustees of such schemes
                  have duly complied with their respective obligations under the
                  trust deeds and the rules thereof and under the aforementioned
                  legislation and requirements.  All amounts due to the trustees
                  thereof or to any insurance  company in  connection  therewith
                  have been paid.

                  (viii) Neither Trenwick  International nor the trustees of any
                  pension  scheme is engaged in any  litigation  or  arbitration
                  proceedings  in respect of any  Employee  Benefit  Plan or any
                  benefit  provided  thereunder  in relation to the employees or
                  former  employees of Trenwick  International  and there are no
                  current  submissions or referrals to the Pensions Ombudsman or
                  to the  Occupational  Pensions  Advisory Service in respect of
                  Trenwick International or any pension scheme.

                  (ix) No Employee  Benefit  Plan in which  employees  or former
                  employees  of  Trenwick  International   participate  or  have
                  participated  has been or is in the  process  of being  (or is
                  proposed  to be)  wound up (in  whole or in part) or closed to
                  new entrants (in whole or in part).

          Section 3.17   Intellectual Property. Trenwick and its Subsidiaries
own or possess,  or have all necessary rights and licenses in, all patents,
patent  rights,  icenses,  inventions  (whether or not  patentable or reduced to
practice), copyrights (whether registered or unregistered), know-how





                                       31
<PAGE>


(including   trade  secrets  and  other  unpatented   and/or   unpatentable
proprietary or confidential information, systems or procedures),  registered and
unregistered  trademarks,  service marks and trade names and other  intellectual
property rights  (collectively,  "Intellectual  Property")  necessary to conduct
their  business as conducted  and proposed to be conducted  except to the extent
that the failure of Trenwick or its  Subsidiaries to own or have such rights and
licenses in such Intellectual  Property would not reasonably be expected to have
a  Material  Adverse  Effect  on  Trenwick.  Neither  Trenwick  nor  any  of its
Subsidiaries  have received any unresolved notice of, or is aware of any fact or
circumstance  that  would give any  Person a right to  assert,  infringement  or
misappropriation  of, or conflict with,  asserted rights of others or invalidity
or unenforceability of any Intellectual Property owned by Trenwick or any of its
Subsidiaries  with  respect  to any of the  foregoing  which,  singly  or in the
aggregate,  would  reasonably be expected to have a Material  Adverse  Effect on
Trenwick. To the knowledge of Trenwick, the use of such Intellectual Property to
conduct  the  business  and  operations  of  Trenwick  and its  Subsidiaries  as
conducted  or proposed to be  conducted  does not  infringe on the rights of any
person in any case where such infringement  would reasonably be expected to have
a Material Adverse Effect on Trenwick.  To the knowledge of Trenwick,  no person
is  challenging,  infringing on or otherwise  violating any right of Trenwick or
any of its  Subsidiaries  with  respect to any  Intellectual  Property  owned by
and/or licensed to Trenwick or any of its  Subsidiaries.  Except as set forth in
Section 3.17 of the Trenwick  Disclosure  Letter,  neither the execution of this
Agreement  or  the  Stock  Option   Agreements  nor  the   consummation  of  the
transactions  contemplated hereby or thereby will result in a loss or limitation
in the  rights  and  licenses  of  Trenwick  to use or enjoy the  benefit of any
Intellectual  Property  employed  by  Trenwick  or any of  its  Subsidiaries  in
connection with its business as conducted or proposed to be conducted where such
loss or  limitation,  individually  or in the  aggregate,  would  reasonably  be
expected to have a Material Adverse Effect on Trenwick.  Following the Effective
Date, Trenwick's Intellectual Property may be used by New Holdings or any of its
Subsidiaries,  except to the extent that failure to be so able to use Trenwick's
Intellectual  Property would not have a Material  Adverse Effect on New Holdings
or any of its Subsidiaries.

          Section 3.18    Takeover  Statutes.  No "fair price,"  "moratorium,"
"control  share  acquisition"  or other  similar  anti-takeover  statute or
regulation  enacted under any Delaware law is applicable to the Plans, the Stock
Option  Agreements  or the other  transactions  contemplated  hereby or thereby.
Trenwick has taken all corporate  action  necessary to render the  provisions of
Section 203 of the GCL  inapplicable to the Plans,  the Stock Option  Agreements
and the other transactions contemplated hereby and thereby.

         Section 3.19      Opinion of  Financial  Advisor.  Trenwick  has
received the written opinion of Donaldson, Lufkin & Jenrette ("DLJ"), dated
December 16, 1999,  to the effect that, as of such date,  the Trenwick  Exchange
Ratio is fair to  Trenwick  from a  financial  point  of  view,  a copy of which
written opinion will be delivered to LaSalle Holdings.

         Section 3.20      Rights Agreement.



                                       32

<PAGE>

         (a)  Trenwick  and its Board of  Directors  have  taken  all  necessary
actions,  including the amendment to the Rights Agreement, so that the execution
and  delivery of this  Agreement,  the LaSalle  Stock  Option  Agreement  or the
consummation of the  transactions  contemplated  hereby and thereby will not (i)
cause any of the Rights to become  exercisable,  (ii) cause LaSalle  Holdings or
New Holdings to be an Acquiring  Person (as defined in the Rights  Agreement) or
(iii) trigger other provisions of the Rights Agreement, including giving rise to
a  Distribution  Date (as defined in the Rights  Agreement),  and the Expiration
Date (as defined in the Rights  Agreement) of the Rights shall occur immediately
prior to the Effective  Time.  Such amendment  shall be in full force and effect
from and after the date hereof.

         (b) Trenwick has taken all necessary  action with respect to all of the
outstanding  Rights so that, as of immediately  prior to the Effective Time, (i)
none of Trenwick,  New Holdings,  LaSalle  Holdings,  LaSalle Re and Acquisition
will have any obligations  under the Rights or the Rights Agreement and (ii) the
holders  of the  Rights  will have no  rights  under  the  Rights or the  Rights
Agreement.

         Section 3.21   Insurance Matters.

         (a) All insurance,  reinsurance and coinsurance treaties or agreements,
including  retrocessional  agreements,  to which  Trenwick or any  Trenwick
Insurance Subsidiary or any syndicate managed by any Trenwick Managing Agency is
a party or under which  Trenwick or any  Trenwick  Insurance  Subsidiary  or any
syndicate  managed by any Trenwick  Managing  Agency,  has any existing  rights,
obligations  or  liabilities  are in full  force  and  effect,  except  for such
treaties or  agreements  the failure to be in full force and effect of which are
not reasonably  expected to have,  individually or in the aggregate,  a Material
Adverse Effect on Trenwick.

         (b) Prior to the date hereof,  Trenwick has delivered or made available
to  LaSalle  Holdings  a true and  complete  copy of the most  recent  actuarial
reports  prepared  by  actuaries,  independent  or  otherwise,  with  respect to
Trenwick or any Trenwick  Insurance  Subsidiary  since December 31, 1998 and all
attachments,  addenda,  supplements  and  modifications  thereto (the  "Trenwick
Actuarial  Analyses").  The  information  and data  furnished by Trenwick or any
Trenwick  Insurance  Subsidiary to its independent  actuaries in connection with
the  preparation  of Trenwick  Actuarial  Analyses were accurate in all material
respects.

         (c)     Except as disclosed in Section 3.21 of the Trenwick Disclosure
                 Letter:

                  (i) All in-force primary insurance policies issued by Trenwick
                  or  any of  its  Insurance  Subsidiaries  are,  to the  extent
                  required   under   applicable   insurance   laws,   rules   or
                  regulations,  on forms and at rates  approved by the insurance
                  regulatory  authority of the jurisdiction where issued or have
                  been filed with and not objected to by such  authority  within
                  the  period  provided  for  objection,  except  as  would  not
                  individually  or in  the  aggregate  have a  Material  Adverse
                  Effect on Trenwick.




                                       33

<PAGE>

                  (ii)  To the  knowledge  of  Trenwick,  except  as  would  not
                  individually  or in  the  aggregate  have a  Material  Adverse
                  Effect  on  Trenwick,   each  insurance  agent  or  solicitor,
                  including, without limitation,  salaried employees of Trenwick
                  or any Insurance Subsidiary appointed as an insurance agent or
                  solicitor,  at the time which agent or solicitor wrote,  sold,
                  solicited or produced  business for such insurer since January
                  1, 1996, was duly licensed as an insurance agent (for the type
                  of  business  written,  sold,  solicited  or  produced by such
                  insurance agent or solicitor in the particular jurisdiction in
                  which  such  agent or  solicitor  wrote,  sold,  solicited  or
                  produced such business).

         Section 3.22   Liabilities and Reserves.  Except for instances where
the failure of the following  statements to be true would not reasonably be
expected to have a Material Adverse Effect on Trenwick, (a) the reserves carried
on the financial  statements of each Trenwick  Insurance  Subsidiary  for future
insurance policy benefits,  losses,  claims and similar purposes were, as of the
respective  dates  of  such  financial   statements,   in  compliance  with  the
requirements  for  reserves  established  by the  insurance  departments  of the
jurisdiction  of such Trenwick  Insurance  Subsidiary or (as the case may be) by
Lloyd's,  were  determined  in  accordance  with  generally  accepted  actuarial
standards  and  principles  consistently  applied  and  were  fairly  stated  in
accordance  with sound actuarial and statutory  accounting  principles (it being
understood that no  representation  or warranty is made in this Agreement to the
effect that such  reserves  will prove to be adequate to cover the actual amount
of  liabilities  that are  eventually  paid after the date hereof);  and (b) the
admitted  assets of each  Trenwick  Insurance  Subsidiary  as  determined  under
applicable laws or under Lloyd's regulations are in an amount at least equal to
the minimum amounts required by applicable laws or regulations.

         Section 3.23    Investment  Company.  Neither  Trenwick nor any of its
Subsidiaries   conducts   activities  of,  or  is  otherwise  deemed  under
applicable law to control,  an  "investment  adviser" as such term is defined in
Section  2(a)(20)  of the  Investment  Company  Act of  1940,  as  amended  (the
"Investment  Company  Act"),  whether  or not  registered  under the  Investment
Advisers  Act of 1940,  as amended  (the  "Investment  Advisers  Act").  Neither
Trenwick nor any of its Subsidiaries is an "investment company" as defined under
the  Investment  Company Act and neither  Trenwick  nor any of its  Subsidiaries
sponsors any Person that is such an investment company.

         Section 3.24   Finite Risk Reinsurance. Except as set forth in Section
3.24  of the  Trenwick  Disclosure  Letter,  none of  Trenwick's  Insurance
Subsidiaries  has ceded business  pursuant to a reinsurance  agreement that does
not meet the conditions for reinsurance  accounting as provided by the Statement
of  Financial  Accounting  Standards  No. 113,  "Accounting  and  Reporting  for
Reinsurance of Short-Duration and Long-Term Contracts."

         Section 3.25   Reinsurance Contracts, Coverholders and MGAs.

         (a) Section 3.25 of the Trenwick  Disclosure  Letter contains a true
and complete list of all managing general agents ("MGAs") and coverholders with
whom each  Subsidiary of Trenwick does business that have been appointed within
the twelve  (12)  months preceding the date of this Agreement  and all in force



                                       34

<PAGE>

contracts,  treaties  or  arrangements  regarding  the  credit  of  reinsurance,
coinsurance, excess insurance (collectively,  the "Reinsurance Contracts") which
generate  premium  income  in  excess  of  $1,000,000  .  Except  as would  not,
individually  or in the aggregate,  have a Material  Adverse Effect on Trenwick:
(i)  each of the  foregoing  Reinsurance  Contracts  is  valid  and  binding  in
accordance with its terms,  and is in full force and effect and (ii) neither the
Subsidiaries  of Trenwick  nor, to the  knowledge  of  Trenwick,  or other party
thereto,  is in  default  in any  material  respect  with  respect  to any  such
Reinsurance Contract,  nor to the knowledge of Trenwick does any condition exist
that  with  notice or lapse of time or both  would  constitute  such a  material
default  thereunder.  Except  as set  forth  in  Section  3.25  of the  Trenwick
Disclosure  Letter,  none  of the  contracts,  treaties  or  arrangements  which
generate  premium  income  in  excess  of  $1,000,000   involving  the  MGAs  or
coverholders with whom each Subsidiary of Trenwick does business contain "change
of control"  provisions and no such Reinsurance  Contract contains any provision
providing that any such other party thereto may terminate, cancel or commute the
same by reason of the  transactions  contemplated by this Agreement or any other
provision  which would be altered or otherwise  become  applicable  by reason of
such transactions, and no party has given notice of termination, cancellation or
commutation  of any such  Reinsurance  Contract or that it intends to terminate,
cancel or commute any such Reinsurance  Contract as a result of the transactions
contemplated hereby.

         (b)  Except as set forth in  Section  3.25 of the  Trenwick  Disclosure
Letter,  Trenwick America  Reinsurance  Company ("TARCO") is entitled under
applicable insurance laws, rules and regulations to take credit in its statutory
financial  statements  in  accordance  with  Chapter  22 of the NAIC  Accounting
Practices and Procedures Manual for Property and Casualty Insurance Companies as
in effect on the date  hereof,  with respect to those  Reinsurance  Contracts to
which it is a party and all such amounts are properly reflected in the statutory
financial  statements  of  TARCO.  Except as set  forth in  Section  3.25 of the
Trenwick Disclosure Letter,  Trenwick International is entitled under applicable
insurance laws, rules and regulations to take credit in its statutory  financial
statements  in  accordance  with  Lloyd's  regulations  as in effect on the date
hereof,  with respect to those Reinsurance  Contracts to which it is a party and
all such amounts are properly reflected in the statutory financial statements of
Trenwick International.  Each of Trenwick,  TARCO and Trenwick International has
no knowledge of any disputes as to reinsurance or retrocessional coverage under,
or any terms of provisions of, any such Reinsurance Contract except as would not
reasonably be expected to have,  individually  or in the  aggregate,  a Material
Adverse Effect on Trenwick.  To the knowledge of Trenwick and TARCO and Trenwick
International,   the  financial  condition  of  any  other  party  to  any  such
Reinsurance  Contract is not  impaired  to the extent that a default  thereunder
could reasonably be expected to occur.

         Section 3.26  Derivatives.  As of the date  hereof,  other  than as set
forth in Section 3.26 of the Trenwick  Disclosure Letter,  neither Trenwick
nor any of its  Subsidiaries  is a party to any  futures  or  option  contracts,
swaps,  hedges or similar  instruments which,  individually or in the aggregate,
could have a Material Adverse Effect on Trenwick.

         Section 3.27  Related Party  Transactions.  Except as set forth in
Section 3.27 of the Trenwick  Disclosure Letter,  since September 30, 1999,
there have been no  transactions,  agreements,  arrangements  or  understandings
between Trenwick and its Subsidiaries,  on the one hand, and Trenwick affiliates
(other than wholly-owned Subsidiaries of Trenwick) or other Person, on the other
hand,  in  existence  as of the date  hereof that are or would be required to be
disclosed in the Trenwick SEC Reports in accordance  with Item 404 of Regulation
S-K under the Securities Act.




                                       35

<PAGE>

                                    ARTICLE 4

               REPRESENTATIONS AND WARRANTIES OF LASALLE HOLDINGS

         LaSalle  Holdings  hereby  represents  and warrants to Trenwick and the
Minority Shareholders that:

         Section 4.1       Corporation; Organization.

         (a) Except as set forth in  Section  4.1(a) of the  LaSalle  Disclosure
Letter,  each  of  LaSalle  Holdings  and its  Subsidiaries  is a  company  duly
organized,   validly  existing  and  in  good  standing  (with  respect  to
jurisdictions that recognize such concept) under the laws of the jurisdiction of
its  organization.  Each  of  LaSalle  Holdings  and  its  Subsidiaries  (i)  is
qualified,  licensed or domesticated  as a foreign company in all  jurisdictions
where  such  qualification,  license or  domestication  is  required  to own and
operate its  properties and conduct its business in the manner and at the places
presently conducted; (ii) holds all franchises, grants, licenses,  certificates,
permits,  consents  and  orders,  all of which are  valid and in full  force and
effect, from all applicable Bermuda and foreign regulatory authorities necessary
to own and operate its  properties and to conduct its business in the manner and
at the  places  presently  conducted;  and  (iii) has full  power and  authority
(corporate and other) to own,  lease and operate its  respective  properties and
assets and to carry on its business as presently conducted and as proposed to be
conducted, except where the failure to be so qualified, licensed or domesticated
or to hold such franchises,  grants, licenses,  certificates,  permits, consents
and orders or to have such power and authority  would not,  when taken  together
with all other such failures,  reasonably be expected to have a Material Adverse
Effect on LaSalle Holdings.  LaSalle Holdings has furnished to Trenwick complete
and correct copies of its memorandum of association and bye-laws as in effect on
the date hereof.  Such  memorandum of association and bye-laws are in full force
and effect and no other  constitutional  documents are  applicable to or binding
upon LaSalle Holdings.

         (b) LaSalle Holdings  conducts its reinsurance  operations  through the
Subsidiaries  set forth in  Section  4.1(b)  of the  LaSalle  Disclosure  Letter
(collectively,  the  "LaSalle  Reinsurance  Subsidiaries").  Each of the LaSalle
Reinsurance  Subsidiaries  is (i) duly  licensed or authorized as a reinsurer in
its  jurisdiction of organization or duly licensed to operate in the reinsurance
business (as applicable) in its jurisdiction of organization, (ii) duly licensed
or authorized as a reinsurer in each other  jurisdiction where it is required to
be so  licensed or  authorized  or duly  licensed to operate in the  reinsurance
business in each other  jurisdiction  where it is required to be so licensed and
(iii)  duly  authorized  in its  jurisdiction  of  organization  and each  other
applicable jurisdiction to write each line of business currently written by such
LaSalle Reinsurance Subsidiaries, except, in any such case, where the failure to
be so licensed or authorized is not reasonably expected to have, individually or
in the aggregate,  a Material Adverse Effect on LaSalle Holdings.  Except as set
forth in Section 4.1(b) of the LaSalle Disclosure  Letter,  LaSalle Holdings has
made all required  filings under applicable  insurance  holding company statutes
except where the failure to file is not  reasonably  expected to have a Material
Adverse Effect on LaSalle Holdings.




                                       36

<PAGE>

         Section 4.2     Authority; Approval and Fairness.

         (a) LaSalle Holdings has all requisite corporate power and authority to
execute and deliver  this  Agreement  and,  subject to the due approval and
adoption of this  Agreement  by its  shareholders,  to perform  its  obligations
hereunder and consummate the transactions  contemplated hereby. LaSalle Holdings
has all requisite  corporate  power and authority to enter into the Stock Option
Agreements  and  to  consummate  the  transactions   contemplated  thereby.  The
execution and delivery of this Agreement by LaSalle Holdings, the performance by
LaSalle  Holdings of its obligations  hereunder and the  consummation by LaSalle
Holdings of the  transactions  contemplated  hereby have been duly authorized by
all necessary corporate action on the part of LaSalle Holdings,  subject only to
compliance  with the  provisions  of Section 99 of the  Companies  Act. No other
corporate  proceedings  on the part of LaSalle  Holdings are  necessary  for the
execution and delivery of this  Agreement by LaSalle  Holdings  and,  subject to
compliance  with  the  provisions  of  Section  99 of  the  Companies  Act,  the
performance  by  LaSalle   Holdings  of  its   obligations   hereunder  and  the
consummation by LaSalle Holdings of the transactions  contemplated  hereby. This
Agreement and the Stock Option  Agreements have been duly executed and delivered
by LaSalle Holdings and, assuming the due authorization,  execution and delivery
hereof and thereof by Trenwick, New Holdings and Acquisition, and subject to the
provisions of Section 99 of the Companies Act constitutes  the legal,  valid and
binding obligations of LaSalle Holdings, enforceable against LaSalle Holdings in
accordance its terms,  subject with respect to  enforceability  to the effect of
bankruptcy,  fraudulent conveyance,  insolvency,  reorganization,  moratorium or
similar laws now or hereafter  affecting the  enforcement  of creditors'  rights
generally and to the availability of equitable remedies.

         (b) The Board of Directors of LaSalle  Holdings (the  "LaSalle  Board")
(i) has unanimously (by all directors present at a meeting duly called and held)
declared that it considers this  Agreement,  the Scheme of  Arrangement  and the
other transactions contemplated hereby to be advisable and in the best interests
of LaSalle Holdings and its shareholders and (ii) has authorized and approved in
all respects this Agreement,  the Plans and the other transactions  contemplated
hereby.

         Section 4.3      Capital Structure.

         (a) As of the date  hereof,  the  authorized  share  capital of LaSalle
Holdings is  $100,000,000  comprised of  100,000,000  shares with a par value of
$1.00 per share. As of December 15, 1999, (i) 15,603,570 LaSalle Holdings Shares
were  issued and  outstanding,  (ii) no  LaSalle  Holdings  Shares  were held as
treasury shares or by Subsidiaries of LaSalle Holdings and (ii) 3,000,000 Series
A Preferred Shares were issued and outstanding. In addition, there are 4,000,000
Series B Preferred Shares of LaSalle Holdings  reserved for issuance pursuant to
the CatEPut,  which shares are convertible into LaSalle Holdings Shares. Section
4.3(a) of the LaSalle  Disclosure  Letter sets forth each plan,  arrangement or



                                       37

<PAGE>

agreement pursuant to which options or stock appreciation rights with respect to
LaSalle  Holdings  Shares or shares of LaSalle Re may be granted or under  which
such options or stock appreciation  rights have been granted and are outstanding
(the "LaSalle  Option Plans") and in the aggregate the maximum number of options
and stock  appreciation  rights  outstanding as of the date hereof and the class
and number of LaSalle  Holdings  Shares or shares of  LaSalle  Re  reserved  for
issuance pursuant to the plan, arrangement or agreement (such options and rights
being herein collectively  referred to as the "LaSalle Holdings Options" and the
"LaSalle  Re  Options,"  as the case may be),  together  with a  listing  of the
aggregate  number of such LaSalle  Holdings Options and LaSalle Re Options which
shall  vest  at  the  Scheme  Effective  Time  as a  result  of  the  Scheme  of
Arrangement.  Except as set forth in Section  4.3(a) of the  LaSalle  Disclosure
Letter,  each of the outstanding  shares of each Subsidiary of LaSalle Holdings,
other than the Non-Voting Shares owned by the Minority Shareholders, is directly
or indirectly owned by LaSalle Holdings, free and clear of all Liens.

         (b) Except as  described  in Section  4.3(b) of the LaSalle  Disclosure
Letter,  as of the date hereof, no Voting Debt of LaSalle Holdings or any of its
Subsidiaries is issued or outstanding.

         (c) Except as  described in Section  4.3(a),  (b) or (c) of the LaSalle
Disclosure Letter, as of the date hereof,  there are no options,  warrants,
calls,  rights,  commitments  or  agreements  of any  character to which LaSalle
Holdings or any of its  Subsidiaries is a party or by which any of them is bound
obligating  LaSalle  Holdings or any of its  Subsidiaries  to issue,  deliver or
sell, or cause to be issued,  delivered or sold, additional shares or any Voting
Debt or obligating LaSalle Holdings or any of its Subsidiaries to grant,  extend
or enter into any such option,  warrant,  call, right,  commitment or agreement.
Except as set  forth in this  Agreement  or in  Section  4.3(c)  of the  LaSalle
Disclosure Letter, as of the date hereof,  there are no outstanding  contractual
obligations of LaSalle Holdings or any of its Subsidiaries to repurchase, redeem
or otherwise acquire any shares of LaSalle Holdings or any of its Subsidiaries.

         (d) Except as  described  in Section  4.3(d) of the LaSalle  Disclosure
Letter or as  specifically  described in this Agreement and except for quarterly
dividends  in an amount not in excess of $0.375 per LaSalle  Holdings  Share and
$1.0938 per Series A Preferred Share,  since June 30, 1999, LaSalle Holdings has
not (i) made or agreed to make any share split or share  dividend,  or issued or
permitted or agreed to permit to be issued any shares, or securities exercisable
for or convertible  into shares,  of LaSalle Holdings other than pursuant to and
as required  by the terms of any  LaSalle  Holdings  Option;  (ii)  repurchased,
redeemed  or  otherwise  acquired  any  shares  of  LaSalle  Holdings;  or (iii)
declared,  set  aside,  made or paid to the  shareholders  of  LaSalle  Holdings
dividends or other distributions on the outstanding shares of LaSalle Holdings.

         (e) Except as  described  in Section  4.3(e) of the LaSalle  Disclosure
Letter or as  specifically  described in this Agreement and except for quarterly
dividends  in an amount not in excess of $0.375 per Minority  Share,  since June
30, 1999, LaSalle Re has not (i) made or agreed to make any share split or share
dividend, or issued or permitted or agreed to permit to be issued any shares, or
securities  exercisable for or convertible into shares, of LaSalle Re other than
pursuant  to and as  required  by the  terms  of any  LaSalle  Re  Option;  (ii)
repurchased,  redeemed or otherwise  acquired any shares of LaSalle Re; or (iii)
declared,  set aside, made or paid to the shareholders of LaSalle Re (other than
LaSalle Holdings)  dividends or other distributions on the outstanding shares of
LaSalle Re.



                                       38

<PAGE>


         Section 4.4  SEC Reports; Financial Statements. Except as set forth in
Section 4.4 of the LaSalle Disclosure Letter,

         (a) LaSalle Holdings has delivered or made available to Trenwick a true
and  complete  copy  of  each  report,  schedule,   registration  statement  and
definitive proxy statement or information  statement  (including exhibits) filed
by LaSalle Holdings with the SEC in respect of its fiscal years ending September
30, 1997 and 1998 and its  quarters  ending after  September  30, 1998 under the
Securities  Act and the Exchange Act and will deliver to Trenwick  promptly upon
the  filing  thereof  with the SEC all  such  reports,  schedules,  registration
statements and proxy statements  (including  exhibits) as may be filed after the
date hereof and prior to the Effective  Time (as such  documents  have since the
time of their filing been amended or may after their  filing,  if after the date
hereof,  be amended,  the "LaSalle SEC  Reports"),  which are or will be all the
documents  that  LaSalle  Holdings was or will be required to file with the SEC.
Except as disclosed in Section 4.4(a) of the LaSalle  Disclosure  Letter,  as of
their  respective  dates, the LaSalle SEC Reports complied or will comply in all
material  respects with the  requirements  of the Securities Act or the Exchange
Act,  as the case may be, and the rules and  regulations  of the SEC  thereunder
applicable  to the  LaSalle  SEC  Reports,  and none of the  LaSalle SEC Reports
contained or will contain any untrue  statement of a material fact or omitted or
will omit to state a material fact required to be stated therein or necessary to
make the statements therein, in light of the circumstances under which they were
made or will be made, not misleading.

         (b) As of their respective  dates, the financial  statements of LaSalle
Holdings  included or to be included  in the LaSalle SEC Reports  (the  "LaSalle
Financial  Statements")  complied  or will  comply  as to  form in all  material
respects with applicable  accounting  requirements  and with the published rules
and  regulations  of the SEC with  respect  thereto and present or will  present
fairly in all material respects the consolidated  financial  position of LaSalle
Holdings  and its  Subsidiaries  and the  consolidated  results  of  operations,
changes in  shareholders'  equity and cash  flows of  LaSalle  Holdings  and its
Subsidiaries as of the dates and for the periods  indicated,  in accordance with
GAAP applied on a  consistent  basis,  subject in the case of interim  financial
statements to normal year-end  adjustments and except for the absence of certain
footnote information in the unaudited statements.

         (c)  Except as set forth in, or arising  out of facts or  circumstances
disclosed in, filings by LaSalle Holdings with the SEC prior to the date hereof,
LaSalle  Holdings and its  Subsidiaries  have no liabilities,  debts,  claims or
obligations of any nature on the date hereof, whether accrued,  absolute, direct
or indirect,  contingent or otherwise,  whether due or to become due, that would
be required to be included on a balance sheet  prepared in accordance  with GAAP
("LaSalle  Liabilities"),   and  there  is  no  existing  condition  or  set  of
circumstances  which  would  reasonably  be  expected  to  result  in a  LaSalle
Liability, except for (i) LaSalle Liabilities incurred in the ordinary and usual
course of business and consistent  with past practice since June 30, 1998,  (ii)
LaSalle  Liabilities  incurred  in  connection  with  or  as  a  result  of  the
transactions  contemplated by this Agreement and (iii) LaSalle  Liabilities that
would not  reasonably be expected to have a Material  Adverse  Effect on LaSalle
Holdings.



                                       39

<PAGE>


         Section 4.5  Absence of Certain Changes or Events. Except in connection
with this  Agreement,  the  Plans,  the  Stock  Option  Agreements  and the
transactions  contemplated  hereby and thereby, as disclosed in the LaSalle
SEC Reports  filed and publicly  available  prior to the date of this  Agreement
(the "Filed  LaSalle  SEC  Reports")  since the date of the most recent  audited
financial statements included in the Filed LaSalle SEC Reports, LaSalle Holdings
and its  Subsidiaries  have  conducted  their  business in the  ordinary  course
consistent  with past  practice,  and there  has not  occurred  (i) any event or
change  having  individually  or in the aggregate a Material  Adverse  Effect on
LaSalle Holdings, (ii) any declaration, setting aside or payment of any dividend
or other  distribution  (whether in cash, stock or property) with respect to any
of LaSalle  Holdings's  outstanding  capital stock, other than regular quarterly
dividends  in an amount  payable in cash not in excess of  $1.0938  per Series A
Preferred  Share and  quarterly  dividends  in an amount  payable in cash not in
excess of $0.375 per LaSalle  Holdings Share,  Voting Share and Non-Voting Share
and  dividends  paid by wholly  owned  Subsidiaries,  (iii) (A) any  granting by
LaSalle Holdings or any of its Subsidiaries to any current or former director or
officer of LaSalle Holdings or its Subsidiaries of any increase in compensation,
bonus or other benefits,  except for normal  increases in the ordinary course of
business, (B) any granting by LaSalle Holdings or any of its Subsidiaries to any
such  current or former  director  or officer of any  increase in  severance  or
termination pay or (C) any entry by LaSalle  Holdings or any of its Subsidiaries
into, or any amendments of, any employment,  deferred compensation,  consulting,
severance,  termination  or  indemnification  agreement with any such current or
former  director or officer,  (iv) any tax election that  individually or in the
aggregate would have a Material Adverse Effect on LaSalle Holdings or any of its
tax  attributes  or any  settlement  or  compromise  of any material  income tax
liability,  or (v) any change in accounting methods,  principles or practices by
LaSalle Holdings or any of its Subsidiaries  materially  affecting their assets,
liabilities  or business,  except insofar as may have been required or permitted
by a change in applicable accounting principles (including SAP).

         Section 4.6. Certain Fees. No finder,  broker, agent, financial advisor
or other  intermediary,  other than Lazard Freres & Co. LLC,  Salomon Smith
Barney  Inc.  and Aon  Capital  Markets,  Inc.,  have acted on behalf of LaSalle
Holdings in  connection  with this  Agreement or the  transactions  contemplated
hereby or is entitled to any payment in connection  herewith.  LaSalle  Holdings
has  provided to Trenwick  copies of LaSalle  Holdings'  engagement  letter with
Lazard Freres & Co. LLC, Salomon Smith Barney Inc. and Aon Capital Markets, Inc.
in connection with this Agreement and the transactions contemplated hereby.

         Section 4.7   No Defaults.   Neither LaSalle Holdings nor any of its
Subsidiaries is in default or violation (and no event has occurred which with
notice or lapse of time or both would  constitute  a default or  violation)  of
its  memorandum  of association or bye-laws or other governing  document or any
material agreement, mortgage,  indenture,  debenture,  trust, lease, license or




                                       40

<PAGE>

other  instrument or obligation to or by which it or any of its  properties
is subject or bound (the  "LaSalle  Instruments"),  except for such  defaults or
violations as would not reasonably be expected to have,  individually  or in the
aggregate, a Material Adverse Effect on LaSalle Holdings. Except as set forth in
Section  4.7 of the LaSalle  Disclosure  Letter,  the  execution,  delivery  and
performance of this Agreement and the taking of any other action contemplated by
this Agreement will not (i) result in any violation of or be in conflict with or
constitute a breach or default (with or without notice or lapse of time or both)
under (a) the memorandum of  association or bye-laws of LaSalle  Holdings or its
Subsidiaries  or (b) any of the other LaSalle  Instruments,  except for any such
violation  of,  conflict  with,  breach  of or  default  under  which  would not
reasonably be expected to have,  individually  or in the  aggregate,  a Material
Adverse  Effect on  LaSalle  Holdings,  (ii)  result in or  constitute  an event
entitling any party to a LaSalle  Holdings  Instrument to effect an acceleration
of  the  maturity  of  any  indebtedness  of  LaSalle  Holdings  or  any  of its
Subsidiaries  or an increase in the rate of  interest  presently  in effect with
respect to such  indebtedness,  except for any such  accelerations  or increases
which  would  not  reasonably  be  expected  to  have,  individually  or in  the
aggregate,  a Material Adverse Effect on LaSalle Holdings or (iii) result in the
creation of any Lien upon any of the  properties or assets of LaSalle  Holdings,
except for Permitted  Liens and any Liens which would not reasonably be expected
to have,  individually or in the aggregate, a Material Adverse Effect on LaSalle
Holdings.

         Section 4.8  Consents.  Except  as set  forth  in  Section 4.8  of the
 LaSalle  Disclosure Letter and except for compliance with the provisions of
Section 99 of the  Companies  Act, the  approval of Lloyd's,  the consent of the
Court to the Plans and the  filing of the order or orders of the Court  pursuant
to Section 2.2 of this Agreement,  no Consent is required on the part of LaSalle
Holdings or any of its  Subsidiaries in connection with the execution,  delivery
and  performance by LaSalle  Holdings of this Agreement and the  consummation by
LaSalle Holdings of the transactions  contemplated hereby, except those required
by (i) compliance  with any applicable  requirements of the HSR Act, (ii) United
States  federal and state  securities or "Blue Sky" laws and (iii) where failure
to obtain  such  Consent  would not  reasonably  be  expected to have a Material
Adverse Effect on LaSalle Holdings.

         Section 4.9  Compliance  with  Applicable  Law.    Each of LaSalle
Holdings and its  Subsidiaries is in compliance with all licenses,  permits
and  other  authorizations,  domestic  or  foreign,  necessary  to  conduct  its
respective business,  except where failure to have or comply with such licenses,
permits  and   authorizations   would  not   reasonably  be  expected  to  have,
individually or in the aggregate, a Material Adverse Effect on LaSalle Holdings.
Neither LaSalle  Holdings nor any of its Subsidiaries is in default or violation
(and no event has occurred  which with notice or the lapse of time or both would
constitute a default or violation) of any judgment, decree, order, law, statute,
rule or regulation of any  Governmental  Authority,  except for such defaults or
violations as would not reasonably be expected to have,  individually  or in the
aggregate,  a Material Adverse Effect on LaSalle Holdings.  Subject to obtaining
the Consents referred to in Section 4.8, the execution, delivery and performance
of this Agreement by LaSalle  Holdings and the  consummation by LaSalle Holdings
of the transactions  contemplated  hereby prior to the date or dates as of which
the  representations  and  warranties  herein are made or deemed made,  will not
result in any default or violation of any judgment, decree, order, law, statute,
rule or regulation of any Governmental  Authority applicable to LaSalle Holdings
or its  Subsidiaries,  except  for such  defaults  or  violations  as would  not
reasonably be expected to have,  individually  or in the  aggregate,  a Material
Adverse Effect on LaSalle Holdings.



                                       41

<PAGE>


         Section 4.10  Information  Supplied.  None of the  information
supplied  or  to  be  supplied  by  LaSalle   Holdings  for   inclusion  or
incorporation  by  reference  in the Form  S-4 to be  filed  with the SEC by New
Holdings  relating to the New Holdings Shares comprising  LaSalle  Consideration
and Trenwick Consideration will, at the time the Form S-4 is filed with the SEC,
at any time it is amended or  supplemented  or at the time it becomes  effective
under the  Securities  Act,  contain any untrue  statement of a material fact or
omit to state any material  fact  required to be stated  therein or necessary to
make the  statements  therein,  in light of the  circumstances  under which such
statements were made, not misleading.  The letters to  shareholders,  notices of
meetings,   proxy   statements  and  forms  of  proxies  to  be  distributed  to
shareholders of LaSalle Holdings and stockholders of Trenwick,  respectively, in
connection  with the  Plans and the  transactions  contemplated  hereby,  except
information  supplied by Trenwick  in writing for  inclusion  in the Joint Proxy
Statement, will not, as of the date the Joint Proxy Statement is first mailed to
such  shareholders  and on  the  date  of  the  meetings  of  LaSalle  Holdings'
shareholders or Trenwick's stockholders, as the case may be, and the date of any
postponement or adjournment thereof,  contain any untrue statement of a material
fact or omit to state  any  material  fact  required  to be  stated  therein  or
necessary in order to make the statements therein, in light of the circumstances
under which they were made, not misleading.  All documents that LaSalle Holdings
is responsible for filing with any Governmental Authority in connection with the
transactions contemplated hereby will comply as to form in all material respects
with the provisions of any applicable law.

         Section 4.11  Material  Contracts.  Except  as set forth in  Section
4.11 of the LaSalle Disclosure Letter:

         (a) All of the contracts of LaSalle Holdings and its  Subsidiaries that
are  required  to be  described  in the  LaSalle  SEC  Reports or to be filed as
exhibits  thereto are  described in the LaSalle SEC Reports or filed as exhibits
thereto and are in full force and effect.

         (b) Neither LaSalle  Holdings nor any of its Subsidiaries is, as of the
date  hereof,  party to any  agreement  containing  any  provision  or  covenant
limiting in any material  respect the ability of LaSalle  Holdings or any of its
Subsidiaries  (or New  Holdings  or any of its  Subsidiaries  subsequent  to the
Effective  Time) to (i) sell any products or services of or to any other Person,
(ii) engage in any line of business in any  geographical  area or (iii)  compete
with or to obtain  products or services  from any Person or limiting the ability
of any Person to provide  products or services to LaSalle Holdings or any of its
Subsidiaries.

         (c) Neither LaSalle Holdings nor any of its Subsidiaries is a party to
or bound by any contract,  agreement or arrangement which would cause the rights
or obligations of any party thereto to change in the event of the Plans,  except
for any such contract,  agreement or  arrangement  which would not reasonably be
expected to have, individually or in the aggregate, a Material Adverse Effect on
LaSalle Holdings.




                                       42

<PAGE>




         Section 4.12   Taxes. Except as provided in Section 4.12 of the LaSalle
 Disclosure Letter:

         (a) To LaSalle Holdings' knowledge, neither LaSalle Holdings nor any of
its Subsidiaries has, nor has it had, any income which is, or has been,  subject
to the United States federal income tax as income which is effectively connected
with the conduct of a trade or  business  within the United  States,  within the
meaning of Section 882(a)(1) of the Code.  LaSalle Holdings and its Subsidiaries
have filed or caused to be filed with the  appropriate  United  States  federal,
state,  local,  foreign and other  Governmental  Authorities,  all Tax  returns,
information  returns  and  reports  required to be filed on or prior to the date
hereof  (taking  into  account  all  valid  extensions).  All such Tax  returns,
information  returns and  reports  are  complete  and  accurate in all  material
respects.

         (b) LaSalle  Holdings  and its  Subsidiaries  have paid in full or made
adequate  provision (in accordance with GAAP) for the payment of all Taxes shown
to be due on the Tax  returns  referred  to in  Section  4.12(a).  All  material
written assessments of Taxes due and payable by or on behalf of LaSalle Holdings
or any of its Subsidiaries  have either been paid or provided for (in accordance
with GAAP) or are being contested in good faith by appropriate proceedings.

         (c) There are no material Tax claims pending against  LaSalle  Holdings
or any of its  Subsidiaries and LaSalle Holdings does not know of any threatened
claim for Tax deficiencies or any basis for such claims, no material issues have
been raised in any  examination by any taxing  authority with respect to LaSalle
Holdings or any of its Subsidiaries which, by application of similar principles,
reasonably  could be expected to result in a proposed  deficiency  for any other
period not so examined, and there are not now in force any waivers or agreements
by LaSalle Holdings or any of its Subsidiaries for the extension of time for the
assessment  of any  material  Tax,  nor has any such  waiver or  agreement  been
requested  by any taxing  authority.  Neither  LaSalle  Holdings  nor any of its
Subsidiaries  has any liability for any material United States  federal,  state,
local,  foreign or other Taxes of any  corporation  or entity other than LaSalle
Holdings and its Subsidiaries.

         (d) There are no Liens on any of the assets of LaSalle  Holdings or any
of its  Subsidiaries  that arose in  connection  with any  failure  (or  alleged
failure)  to pay any Taxes  (other  than  Taxes  that are not due as of the date
hereof).

         (e) LaSalle  Holdings and its  Subsidiaries  have withheld and paid all
United States federal,  state,  local,  foreign and other Taxes required to have
been withheld and paid in connection with amounts paid or owing to any employee,
independent contractor, creditor, stockholder or other third party.

         (f) To LaSalle  Holdings'  knowledge,  Section  4.12(f) of the  LaSalle
Disclosure Letter  discloses,  with respect to the year ended September 30,
1998 and for the period commencing October 1, 1998 and ending on the date of the
LaSalle  Disclosure  Letter,  (i) each insurance or  reinsurance  transaction by
LaSalle  Holdings  or any of its  Subsidiaries  directly  with  shareholders  of
LaSalle  Holdings and (ii) each insurance or reinsurance  transaction by LaSalle
Holdings or any of its Subsidiaries  directly or indirectly with Persons related
to shareholders of LaSalle Holdings and not disclosed in clause (i) above, which
would cause  LaSalle  Holdings or any of its  Subsidiaries  to have any "related
person insurance income" within the meaning of Section 953(c)(2) of the Code.




                                       43

<PAGE>

         (g)  To  LaSalle   Holdings'   knowledge,   LaSalle  Holdings  and  its
Subsidiaries  did not have for the year ended  September  30, 1998,  and LaSalle
Holdings does not expect LaSalle Holdings or any of its Subsidiaries to have for
the period ending at the Scheme  Effective  Time  (treating such period as if it
were a taxable year),  "related person  insurance  income" within the meaning of
Section  953(c)(2) of the Code in excess of the exceptions  provided in Sections
953(c)(3)(A) and (B) of the Code.

         (h) To LaSalle Holdings' knowledge, neither LaSalle Holdings nor any of
its Subsidiaries  is, nor has LaSalle  Holdings or any of its Subsidiaries  ever
been, a "controlled foreign corporation" within the meaning of Section 957(a) or
957(b) of the Code.

         (i) A  representation  with respect to Taxes  contained in this Section
4.12 shall be deemed to be accurate unless an inaccuracy contained therein would
reasonably be expected to have,  individually  or in the  aggregate,  a Material
Adverse Effect on LaSalle Holdings.

         Section 4.13  Litigation.  Except as disclosed  in the LaSalle SEC
Reports  filed  prior to the  date  hereof  or in  Section  4.13 of the  LaSalle
Disclosure  Letter,  there  are  no  actions,  suits,  claims,   proceedings  or
investigations  pending  against  or,  to the  knowledge  of  LaSalle  Holdings,
threatened against or affecting,  LaSalle Holdings or any of its Subsidiaries or
any  of  their  respective  properties  before  any  Governmental  Authority  or
otherwise which (a) would be expected to have, individually or in the aggregate,
a Material Adverse Effect on LaSalle  Holdings,  (b) in any manner challenges or
seeks to prevent, enjoin, alter or delay the transactions contemplated hereby or
(c) alleges criminal action or inaction. As of the date hereof,  neither LaSalle
Holdings nor its Subsidiaries or any of their  respective  properties is subject
to any order, writ, judgment, injunction, decree, determination or award having,
or which would  reasonably  be expected to have,  a Material  Adverse  Effect on
LaSalle  Holdings  or which  would  prevent  or delay  the  consummation  of the
transactions contemplated hereby. Except as disclosed in the LaSalle SEC Reports
filed prior to the date  hereof,  there are no pending or, to the  knowledge  of
LaSalle Holdings,  threatened claims for  indemnification by LaSalle Holdings or
any of its Subsidiaries in favor of directors, officers, employees and agents of
LaSalle Holdings or any of its Subsidiaries.

         Section 4.14    Title to Properties:     Leases. Except as set forth in
Section 4.14(a) of the LaSalle Disclosure  Letter,  each of LaSalle Holdings and
its  Subsidiaries  has good and marketable title to, and is the lawful owner of,
or has the right to use pursuant to a license or otherwise,  all of the tangible
and  intangible  assets,  properties  and rights used in its  businesses and all
tangible and intangible  assets,  properties and rights reflected on the balance
sheet of LaSalle  Holdings  dated June 30, 1999 or acquired since June 30, 1999,
free and clear of all Liens (other than Permitted  Liens) and material  defects.
LaSalle Holdings and its  Subsidiaries own no real property.  Section 4.14(c) of
the LaSalle Disclosure Letter sets forth all material real property and personal
property leases of LaSalle  Holdings and its  Subsidiaries.  All such leases are
valid,  binding and  enforceable  against LaSalle  Holdings or its  Subsidiaries
(and,  to the  knowledge of LaSalle  Holdings and its  Subsidiaries,  each other
party thereto) in accordance  with their  respective  terms,  and there does not
exist,  under any lease of real  property or  personal  property,  any  material
defect  or any  event  which,  with  notice  or  lapse  of time or  both,  would
constitute a material  default by the LaSalle Holdings or its  Subsidiaries,  as
the case may be, or, to the knowledge of LaSalle Holdings and its  Subsidiaries,
by any other party thereto.



                                       44
<PAGE>


         Section 4.15  Approval of Scheme of Arrangement.  Other than the
affirmative  vote of the holders of at least  seventy-five  percent (75%) of the
issued and outstanding  LaSalle Holdings Shares (with each LaSalle Holding Share
having one vote per share) and at least seventy-five percent (75%) of the issued
and outstanding  Non-Voting  Shares (with each Non-Voting  Share having one vote
per share) to approve and adopt this  Agreement  and the Scheme of  Arrangement,
there is no other  vote,  consent  or  approval  of the  holders of any class of
shares of LaSalle  Holdings  or LaSalle Re  necessary  to approve and adopt this
Agreement, the Scheme of Arrangement and the transactions contemplated hereby.

         Section 4.16  Employees.

         (a) Section 4.16(a) of the LaSalle  Disclosure Letter lists, as of the
date hereof, all employment  contracts and similar  arrangements between LaSalle
Holdings or any of its Subsidiaries and their respective  executive officers and
all plans and  arrangements  pursuant  to which  LaSalle  Holdings or any of its
Subsidiaries  is obligated  to make any payment or confer any  material  benefit
upon any officer, director,  employee or agent of LaSalle Holdings or any of its
Subsidiaries  as a  result  of or in  connection  with  any of the  transactions
contemplated by this Agreement or any transaction or transactions resulting in a
change of control of LaSalle Holdings or any of its Subsidiaries (including as a
result of a termination  of  employment in connection  with any of such events).
Except as  described  in Section  4.16(a) of the LaSalle  Disclosure  Letter and
except as would not reasonably be expected to have a Material  Adverse Effect on
LaSalle  Holdings,  (i) LaSalle Holdings and its Subsidiaries have complied with
all laws  relating to the  employment  of labor,  including  provisions  thereof
relating to wages, hours, equal opportunity and collective  bargaining,  (ii) no
labor  dispute  with  employees of LaSalle  Holdings or any of its  Subsidiaries
exists or, to the  knowledge  of LaSalle  Holdings,  is  threatened,  (iii) each
Employee  Benefit Plan maintained by LaSalle Holdings or any of its Subsidiaries
(each a "LaSalle Employee Benefit Plan") conforms to, and its  administration is
in conformity with, all applicable laws, no liability has been or is expected to
be incurred by LaSalle Holdings or any of its  Subsidiaries  with respect to any
LaSalle Employee Benefit Plan,  except as expressly  provided by such plan, (iv)
no LaSalle  Employee  Benefit Plan is subject to ERISA, (v) LaSalle Holdings has
made  available  to  Trenwick  a true and  correct  copy of each of the  LaSalle
Employee  Benefit Plans and all  applicable  trust  agreements and all contracts
relating  thereto or to the funding  thereof,  (vi) all LaSalle Employee Benefit
Plans intended to satisfy  applicable Tax qualification  requirements,  or other
requirements necessary to secure favorable Tax or other legal treatment, comply




                                       45

<PAGE>

in all material  respects with such requirements and (vii) adequate accruals for
all obligations  under the LaSalle  Employee  Benefit Plans are reflected in the
LaSalle  Financial  Statements.  Except as described  in Section  4.16(a) of the
LaSalle  Disclosure  Letter,  no  agreement,  contract or  arrangement  to which
LaSalle Holdings or any of its Subsidiaries is a party would result in a payment
that would not be deductible as a result of Section 280G of the Code.

         (b)  Except as set forth in Section  4.16(b) of the LaSalle  Disclosure
Letter,  neither LaSalle  Holdings nor any of its Subsidiaries is a party to any
collective  bargaining  or other  labor  union  contract  applicable  to Persons
employed  by  LaSalle  Holdings  or  any  of  its  Subsidiaries,  no  collective
bargaining  agreement  is being  negotiated  by LaSalle  Holdings  or any of its
Subsidiaries  and  LaSalle  Holdings  has  no  knowledge  of any  activities  or
proceedings  of any labor union to organize any of their  respective  employees.
There is no labor dispute,  strike or work stoppage  against LaSalle Holdings or
any of its Subsidiaries pending or, to LaSalle Holdings'  knowledge,  threatened
which may interfere with the respective  business activities of LaSalle Holdings
or any of its Subsidiaries,  except where such dispute,  strike or work stoppage
would not  reasonably be expected to have a Material  Adverse  Effect on LaSalle
Holdings.

         (c)  Except  as  disclosed  in the  Section  4.16(c)  of  the  LaSalle
Disclosure  Letter,  the  consummation  of the  Scheme  of  Arrangement  (or the
approval  thereof  by  the  parties'  respective  shareholders)  and  the  other
transactions  contemplated by this Agreement, will not (x) entitle any employees
or directors of LaSalle or of any LaSalle Holdings Commonly  Controlled  Entity,
directly or indirectly to severance  pay; (y)  accelerate the time of payment or
vesting or trigger any payment of  compensation  or benefits  under, or increase
the amount payable or trigger any other material  obligation pursuant to, any of
the  LaSalle  Benefit  Plans;  or (z) result in any breach or  violation  of, or
default under any of the LaSalle Benefit Plans.

         Section 4.17  Intellectual Property.  LaSalle Holdings and its
Subsidiaries  own or possess,  or have all necessary rights and licenses in, all
Intellectual  Property  necessary to conduct  their  business as  conducted  and
proposed  to be  conducted  except to the  extent  that the  failure  of LaSalle
Holdings or its  Subsidiaries  to own or have such  rights and  licenses in such
Intellectual  Property  would not  reasonably  be  expected  to have a  Material
Adverse  Effect on LaSalle  Holdings.  Neither  LaSalle  Holdings nor any of its
Subsidiaries  have received any unresolved notice of, or is aware of any fact or
circumstance  that  would give any  Person a right to  assert,  infringement  or
misappropriation  of, or conflict with,  asserted rights of others or invalidity
or  unenforceability  of any Intellectual  Property owned by LaSalle Holdings or
any of its Subsidiaries with respect to any of the foregoing which, singly or in
the aggregate, would reasonably be expected to have a Material Adverse Effect on
LaSalle  Holdings.  To the  knowledge  of  LaSalle  Holdings,  the  use of  such
Intellectual Property to conduct the business and operations of LaSalle Holdings
and its  Subsidiaries as conducted or proposed to be conducted does not infringe
on the rights of any person in any case where such infringement would reasonably
be  expected  to have a  Material  Adverse  Effect on LaSalle  Holdings.  To the
knowledge  of  LaSalle  Holdings,  no person is  challenging,  infringing  on or
otherwise  violating  any right of LaSalle  Holdings or any of its  Subsidiaries
with respect to any  Intellectual  Property owned by and/or  licensed to LaSalle
Holdings or any of its Subsidiaries.  Except as set forth in Section 4.17 of the
LaSalle  Disclosure  Letter,  neither the  execution  of this  Agreement  or the
LaSalle  Stock  Option  Agreement  nor  the  consummation  of  the  transactions
contemplated hereby or thereby will result in a loss or limitation in the rights
and licenses of LaSalle Holdings to use or enjoy the benefit of any Intellectual
Property  employed by LaSalle  Holdings or any of its Subsidiaries in connection
with its business as  conducted  or proposed to be conducted  where such loss or
limitation,  individually or in the aggregate,  would  reasonably be expected to
have a Material Adverse Effect on LaSalle Holdings.




                                       46
<PAGE>


Following the Effective Date, LaSalle Holdings Intellectual Property may be used
by New Holdings or any of its Subsidiaries, except to the extent that failure to
be so able to use  LaSalle's  Intellectual  Property  would not have a  Material
Adverse Effect on New Holdings or any of its Subsidiaries.

         Section 4.18  Takeover  Statutes.  No "fair price,"  "moratorium,"
"control share acquisition" or other similar anti-takeover statute or regulation
enacted  under any  Bermuda law is  applicable  to the Plans,  the Stock  Option
Agreements or the other transactions contemplated hereby or thereby.

         Section 4.19   Opinions of Financial  Advisors.  The LaSalle Board has
received  the  separate  opinions of Lazard  Freres & Co. LLC and Salomon  Smith
Barney Inc.,  dated  December 16, 1999, to the effect that, as of such date, the
LaSalle  Exchange Ratio is fair to the holders of LaSalle Holdings Shares from a
financial  point  of view,  copies  of the  written  opinions  of which  will be
delivered to Trenwick.

         Section 4.20   Insurance Matters.

         (a) All insurance,  reinsurance and coinsurance treaties or agreements,
including  retrocessional  agreements,  to which LaSalle Holdings or any LaSalle
Holdings  Reinsurance  Subsidiary is a party or under which LaSalle  Holdings or
any LaSalle Holdings Reinsurance Subsidiary has any existing rights, obligations
or  liabilities  are in full  force and  effect,  except  for such  treaties  or
agreements  the  failure  to be in  full  force  and  effect  of  which  are not
reasonably  expected  to have,  individually  or in the  aggregate,  a  Material
Adverse Effect on LaSalle Holdings.

         (b) Prior to the date hereof,  LaSalle  Holdings has  delivered or made
available  to Trenwick a true and  complete  copy of the most  recent  actuarial
reports prepared by actuaries, independent or otherwise, with respect to LaSalle
Holdings or any LaSalle Holdings Reinsurance Subsidiary since September 30, 1998
and  all  attachments,  addenda,  supplements  and  modifications  thereto  (the
"LaSalle  Actuarial  Analyses").  The  information and data furnished by LaSalle
Holdings or any  LaSalle  Holdings  Reinsurance  Subsidiary  to its  independent
actuaries in connection with the preparation of the LaSalle  Actuarial  Analyses
were accurate in all material respects.

         (c) LaSalle Re does not currently  issue and has not issued any primary
insurance policies in the United States.

         Section 4.21    Liabilities and Reserves.




                                       47
<PAGE>


         Except for instances  where the failure of the following  statements to
be true would not  reasonably be expected to have a Material  Adverse  Effect on
LaSalle Holdings,  (a) the reserves carried on the financial  statements of each
LaSalle  Holdings  Reinsurance  Subsidiary for future insurance policy benefits,
losses,  claims and similar  purposes were, as of the  respective  dates of such
financial   statements,   in  compliance  with  the  requirements  for  reserves
established  by the insurance  departments of the  jurisdiction  of such LaSalle
Holdings  Reinsurance  Subsidiary  or (as  the  case  may be) by  Lloyd's,  were
determined  in  accordance  with  generally  accepted  actuarial  standards  and
principles consistently applied, and were fairly stated in accordance with sound
actuarial and  statutory  accounting  principles  (it being  understood  that no
representation  or  warranty is made in this  Agreement  to the effect that such
reserves were in fact adequate to cover the actual  amount of  liabilities  that
are eventually paid after the date hereof);  and (b) the admitted assets of each
LaSalle Holdings  Reinsurance  Subsidiary as determined under applicable laws or
under Lloyd's regulations are in an amount at least equal to the minimum amounts
required by applicable laws or regulations.

         Section 4.22  Investment  Company.  Neither  LaSalle  Holdings nor any
of its  Subsidiaries  conducts  activities  of,  or is  otherwise  deemed  under
applicable law to control,  an  "investment  adviser" as such term is defined in
Section 2(a)(20) of the Investment  Company Act, whether or not registered under
the  Investment   Advisers  Act.   Neither  LaSalle  Holdings  nor  any  of  its
Subsidiaries is an "investment  company" as defined under the Investment Company
Act and neither LaSalle Holdings nor any of its Subsidiaries sponsors any Person
that is such an investment company.

         Section 4.23     Reinsurance Contracts, Coverholders and MGAs.

         (a) Section 4.23 of the LaSalle  Disclosure  Letter  contains a true
and complete  list of all MGAs and  coverholders  with whom each  Subsidiary  of
LaSalle  Holdings does business that have been appointed  within the twelve (12)
months  preceding  the  date of this  Agreement  and  all in  force  Reinsurance
Contracts  which  generate  premium income in excess of $1,000,000 to which each
subsidiary of LaSalle  Holdings is a party as the cedent  thereunder or by or to
which  each  subsidiary  of LaSalle  Holdings  is bound or subject as the cedent
thereunder, as each such Reinsurance Contract may have been amended, modified or
supplemented.  Except as would not,  individually  or in the  aggregate,  have a
Material  Adverse  Effect  on  LaSalle  Holdings:  (i)  each  of  the  foregoing
Reinsurance  Contracts is valid and binding in accordance with its terms, and is
in full force and effect and (ii) neither the  Subsidiaries of LaSalle  Holdings
nor, to the knowledge of LaSalle Holdings, or other party thereto, is in default
in any material  respect with respect to any such Reinsurance  Contract,  nor to
the knowledge of LaSalle  Holdings does any condition  exist that with notice or
lapse of time or both  would  constitute  such a  material  default  thereunder.
Except as set forth in Section 4.23 of the LaSalle  Disclosure  Letter,  none of
the contracts, treaties or arrangements involving the MGAs or coverholders which
generate  premium  income in excess of $1,000,000  with whom each  Subsidiary of
LaSalle  Holdings does business  contain  "change of control"  provisions and no
such Reinsurance  Contract contains any provision  providing that any such other
party  thereto  may  terminate,  cancel  or  commute  the same by  reason of the
transactions  contemplated  by this Agreement or any other provision which would
be altered or otherwise become applicable by reason of such transactions, and no
party has given notice of  termination,  cancellation or commutation of any such
Reinsurance Contract or that it intends to terminate, cancel or commute any such
Reinsurance Contract as a result of the transactions contemplated hereby.




                                       48

<PAGE>

         (b) Except  as set forth in  Section  4.23 of the  LaSalle  Disclosure
Letter,  LaSalle Re is  entitled  under  applicable  insurance  laws,  rules and
regulations to take credit in its statutory  financial  statements in accordance
with applicable Bermuda law as in effect on the date hereof, with respect to the
Reinsurance  Contracts listed in Section 4.23 of the LaSalle  Disclosure  Letter
and  all  such  amounts  are  properly  reflected  in  the  statutory  financial
statements  of  LaSalle  Re.  Each of  LaSalle  Holdings  and  LaSalle Re has no
knowledge of any disputes as to reinsurance or retrocessional coverage under, or
any terms of provisions of, any such Reinsurance  Contract.  To the knowledge of
LaSalle  Holdings and LaSalle Re, the financial  condition of any other party to
any such  Reinsurance  Contract  is not  impaired  to the extent  that a default
thereunder could reasonably be expected to occur.

         Section 4.24  Derivatives.  As of the date  hereof, other  than as set
forth in Section 4.24 of the LaSalle Disclosure Letter, neither LaSalle Holdings
nor any of its  Subsidiaries  is a party to any  futures  or  option  contracts,
swaps,  hedges or similar  instruments which,  individually or in the aggregate,
could have a Material Adverse Effect on LaSalle Holdings.

         Section 4.25  Related Party  Transactions.  Except as set forth in
Section 4.25 of the LaSalle Disclosure  Letter,  since June 30, 1999, there have
been no transactions, agreements, arrangements or understandings between LaSalle
Holdings and its Subsidiaries, on the one hand, and LaSalle Holdings' affiliates
(other than wholly-owned  Subsidiaries of LaSalle Holdings) or other Persons, on
the other hand, in existence as of the date hereof that are or would be required
to be  disclosed  in the  LaSalle  SEC  Reports in  accordance  with Item 404 of
Regulation S-K under the Securities Act.

         Section 4.26  Finite Risk Reinsurance.  Except as set forth in
Section 4.26 of the LaSalle  Disclosure  Letter,  none of LaSalle's  Reinsurance
Subsidiaries  has ceded business  pursuant to a reinsurance  agreement that does
not meet the conditions for reinsurance  accounting as provided by the Statement
of  Financial  Accounting  Standards  No. 113,  "Accounting  and  Reporting  for
Reinsurance of Short-Duration and Long-Term Contracts."


                                    ARTICLE 5

                                    COVENANTS

         Section 5.1   Conduct of Business of Trenwick. Except as expressly
contemplated by this  Agreement,  the Stock Option  Agreements,  as set forth in
Section 5.1 of the Trenwick  Disclosure  Letter or as consented to in writing by
LaSalle  Holdings,  during the  period  from the date of this  Agreement  to the
Effective Time,  Trenwick shall,  and shall cause each of its  Subsidiaries  to,
conduct  its  operations  and (to the  extent  it is able to  control  them) the
operations of the syndicates  managed by the Trenwick Managing Agencies only in,
and neither Trenwick nor any of its Subsidiaries shall take any action and shall
not take any  action in  relation  to the  syndicates  managed  by the  Trenwick
Managing  Agencies (to the extent they are able to control  them) except in, the
ordinary and usual course of business and  consistent  with past  practice,  and
Trenwick and its Subsidiaries  will use all commercially  reasonable  efforts to
preserve intact their business  organization,  to keep available the services of
their officers and employees and to maintain advantageous relationships with and
the goodwill of their customers, business partners and others



                                       49

<PAGE>

having  business   relationships  with  Trenwick  or  its  Subsidiaries  or  the
syndicates  managed  by the  Trenwick  Managing  Agencies,  as the  case may be.
Without  limiting the generality of the foregoing,  prior to the Effective Time,
neither  Trenwick  nor  any  of  its  Subsidiaries  will,  except  as  expressly
contemplated  by this  Agreement,  without the prior written  consent of LaSalle
Holdings:


         (a) split,  combine  or  reclassify  any shares of its  capital  stock,
declare, pay or set aside for payment any dividend or other distribution payable
in cash,  stock,  property  or  otherwise  in  respect of its  capital  stock or
directly or indirectly  redeem,  purchase or otherwise acquire any shares of any
class of  capital  stock or  other  securities,  other  than  regular  quarterly
dividends  (other than those  payable to Trenwick) in an amount  payable in cash
not in excess  of $0.26 per  share;  after the date of this  Agreement,  LaSalle
Holdings and Trenwick will  coordinate with each other regarding the declaration
of dividends in respect of the Trenwick  Shares and the record dates and payment
dates  relating  thereto,  it being the intention of the parties that holders of
Trenwick Shares will not receive two dividends, or fail to receive one dividend,
for any single  calendar  quarter with respect to their Trenwick  Shares and the
New Holdings Shares any such holder receives in exchange  therefor in accordance
with the Plans;

         (b) authorize for issuance,  issue, sell, grant, pledge,  dispose of or
encumber,  deliver or agree or commit to issue, sell, pledge or deliver (whether
through  the  issue  or  granting  of  any   options,   warrants,   commitments,
subscriptions,  rights to  purchase  or  otherwise)  any  shares of any class of
capital stock of Trenwick or any Subsidiary or any securities  convertible  into
or  exercisable  or  exchangeable  for shares of any class of  capital  stock of
Trenwick,  except as required by  agreements  as in effect as of the date hereof
and disclosed in Section 5.1(b) of the Trenwick  Disclosure Letter, or amend any
of the terms of any such  securities  or agreements  outstanding  as of the date
hereof;

         (c)  (i) incur or assume any debt, except for borrowings, in each case,
in the ordinary course of business consistent with past practices,  (ii) assume,
guarantee,  endorse or otherwise become liable or responsible (whether directly,
contingently  or otherwise) for the  obligations of any other Person,  except in
the ordinary course of business,  (iii) make any loans or advances to any Person
other than loans or advances of  out-of-pocket  expenses  incurred in connection
with the  business  of Trenwick or its  Subsidiaries,  (iv) pledge or  otherwise
encumber shares of capital stock of Trenwick or its Subsidiaries or (v) mortgage
or pledge any of its material assets, tangible or intangible, or create any Lien
thereupon other than Permitted Liens;

         (d)  except  as may be  required  by law  or as  contemplated  by  this
Agreement,  including  Section 5.9, enter into,  adopt or amend or terminate any
bonus, profit sharing, compensation,  severance, termination, change of control,
stock option,  stock  appreciation  right,  restricted stock,  performance unit,
stock  equivalent,  stock  purchase  agreement,  pension,  retirement,  deferred
compensation,   employment,  consulting,  fringe  benefit,  severance  or  other
Employee  Benefit  Plan;  or enter  into or amend any  employment  or  severance
agreement  with any director,  officer,  employee or agent of Trenwick or any of
its Subsidiaries; or increase in any manner the salary, wages, bonus, commission
or other compensation or benefits of any director, officer, employee or agent of
Trenwick  or  any of its  Subsidiaries,  except,  (i)  in  connection  with  the
promotion of any



                                       50

<PAGE>



director,  officer,  employee or agent of Trenwick or any of its Subsidiaries or
(ii) for increases in the ordinary  course of business and consistent  with past
practice  which in the  aggregate  do not exceed 10%; or hire  employees  at the
level of Vice  President  or above;  or pay any benefit not required by any plan
and  arrangement  as in  effect  as  of  the  date  hereof  (including,  without
limitation,  the  granting  of  stock  options,  stock  appreciation  rights  or
performance units);

         (e) acquire (by merger,  amalgamation, consolidation  or acquisition of
stock or assets or  otherwise)  any  corporation,  partnership,  joint  venture,
association  or other  business  organization  or  division  thereof or make any
material investment either by purchase of stock or securities,  contributions to
capital,  property transfer or acquisition  (including by lease) of any material
amount of properties  or assets of any other Person,  except for the purchase of
investment stock or securities in the ordinary course of business;

         (f) pay,  discharge or satisfy any claims,  liabilities  or obligations
(absolute,  accrued,  contingent  or otherwise)  against  Trenwick or any of its
Subsidiaries,  its  directors,  officers,  employees  or agents,  other than the
payment,  discharge  or  satisfaction  in the  ordinary  course of business  and
consistent  with past  practice  of claims for  contractual  benefits  under any
insurance  or   reinsurance   contract  under  which  Trenwick  or  any  of  its
Subsidiaries or syndicates  managed by any of its Subsidiaries is the insurer or
reinsurer;

         (g)  amend or  propose  to amend  the  certificate  of  incorporation,
by-laws or any similar document of Trenwick or any of its Subsidiaries;

         (h) adopt a plan or resolutions providing for the complete or partial
liquidation,   dissolution,    amalgamation,    consolidation,    restructuring,
recapitalization or other reorganization of Trenwick or any of its Subsidiaries;

         (i)  except as set forth in Section  5.1(i) of the Trenwick  Disclosure
Letter,  enter into any new lines of  business  (other than in or related to the
insurance or  reinsurance  business) or otherwise  make material  changes to the
operation of its business or its loss reserve;

         (j) except as set forth in Section  5.1(j) of the  Trenwick  Disclosure
Letter,  sell (whether by  amalgamation,  consolidation  or  otherwise),  lease,
transfer or dispose of any material assets (including without limitation, rights
of  renewal)  outside  the  ordinary  course of  business  consistent  with past
practice  or enter into any  material  commitment  or  transaction  outside  the
ordinary course of business consistent with past practices;




                                       51
<PAGE>

         (k)  authorize  or make or  commit  to make any  capital  expenditures,
except for transactions in the ordinary course of business  consistent with past
practice (but in no event in excess of $1,000,000 in the  aggregate) or pursuant
to agreements or commitments entered into by Trenwick or any of its Subsidiaries
prior to the date hereof;

         (l) make any Tax elections or settle or compromise any material United
States federal,  state, local or other foreign income Tax liability, or waive or
extend the statute of limitations in respect of any such Taxes;

         (m)  except as may be  required  as a result of a change in law or in
GAAP, change any of the accounting principles or practices used by it;

         (n)  amend the Rights or the Rights Agreement in any manner adverse
to LaSalle Holdings;

         (o) enter into any agreement  providing for the acceleration of payment
or  performance  or other  consequence  as a result  of a change in  control  of
Trenwick or any of its Subsidiaries;

         (p)  resolve,  commit or agree to take any of the foregoing actions or
any  action  which  would  make any  representation  or  warranty  in  Article 3
materially untrue or incorrect;

         (q)  make any material  change in its  retrocessional  agreements  or
arrangements,  including without limitation converting any of its funds withheld
stop loss reinsurance  agreements into another type of reinsurance  agreement or
entering  into  new  funds   withheld  stop  loss   reinsurance   agreements  or
arrangements or stop loss reinsurance  agreements or arrangements that attach at
an attachment point less than the expected loss ratio;

         (r)   make any material change in its reinsurance agreements or
arrangements;

         (s) enter into any agreement or  arrangement  that limits or otherwise
restricts  Trenwick or any of its Subsidiaries or any successor  thereto or that
could,  after  the  Effective  Time,  limit or  restrict  New  Holdings  and its
Subsidiaries or any successor thereto, from engaging or competing in any line of
business or in any geographic area; or

         (t)  enter  into  any  new  transaction,   agreement,   arrangement  or
understanding  with any other  Persons that would be required to be disclosed in
the Trenwick SEC Reports in  accordance  with Item 404 of Schedule S-K under the
Securities Act.

         Section 5.2  Conduct  of  Business  of  LaSalle  Holdings.  Except as
expressly contemplated by this Agreement,  the Stock Option Agreements or as set
forth in Section  5.2 of the LaSalle  Disclosure  Letter or as  consented  to in
writing by  Trenwick,  during the period from the date of this  Agreement to the
Effective Time, LaSalle Holdings shall, and shall cause each of its Subsidiaries
to, conduct its operations only in, and neither LaSalle  Holdings nor any of its
Subsidiaries  shall take any action  except in, the ordinary and usual course of
business  and  consistent  with past  practice,  and  LaSalle  Holdings  and its
Subsidiaries  will use all  commercially  reasonable  efforts to preserve intact
their  business  organization,  to keep available the services of their officers
and employees and to maintain  advantageous  relationships with and the goodwill
of their customers,  business partners and others having business  relationships
with LaSalle Holdings or its Subsidiaries,  as the case may be. Without limiting
the generality of the foregoing,  prior to the Effective  Time,  neither LaSalle
Holdings nor any of its Subsidiaries  will, except as expressly  contemplated by
this Agreement, without the prior written consent of Trenwick:



                                       52
<PAGE>

         (a)  split,   combine  or  reclassify  any  shares, declare, pay or set
aside for payment any dividend or other  distribution  payable in cash,  shares,
property or otherwise in respect of its shares or directly or indirectly redeem,
purchase or otherwise  acquire any shares of any class of capital stock or other
securities,  other than regular quarterly dividends (other than those payable to
LaSalle  Holdings)  in an amount  payable in cash not in excess of  $1.0938  per
Series A Preferred  Share and quarterly  dividends in an amount  payable in cash
not in excess of $0.375 per LaSalle Holdings Share and Non-Voting  Share;  after
the date of this Agreement,  LaSalle  Holdings and Trenwick will coordinate with
each other regarding the  declaration of dividends  (other than those payable to
LaSalle Holdings) in respect of the Series A Preferred Shares,  LaSalle Holdings
Shares and  Non-Voting  Shares and the record dates and payment  dates  relating
thereto,  it being the intention of the parties that holders of LaSalle Holdings
Shares and  NonVoting  Shares  will not  receive  two  dividends  for any single
calendar  quarter with respect to their LaSalle  Holdings  Shares and Non-Voting
Shares and the New Holdings Shares any such holder receives in exchange therefor
in accordance with the Plans;

         (b) authorize for issuance,  issue, sell, grant, pledge,  dispose of or
encumber,  deliver or agree or commit to issue, sell, pledge or deliver (whether
through  the  issue  or  granting  of  any   options,   warrants,   commitments,
subscriptions,  rights to  purchase  or  otherwise)  any  shares of any class of
LaSalle  Holdings  or any  Subsidiary  or any  securities  convertible  into  or
exercisable or exchangeable for shares of any class of LaSalle Holdings,  except
as required by  agreements  as in effect as of the date hereof and  disclosed in
Section 5.2(b) of the LaSalle  Disclosure  Letter,  or amend any of the terms of
any such securities or agreements outstanding as of the date hereof;

         (c) (i) incur or assume any debt, except for borrowings, in each case,
in the ordinary course of business consistent with past practices,  (ii) assume,
guarantee,  endorse or otherwise become liable or responsible (whether directly,
contingently  or otherwise) for the  obligations of any other Person,  except in
the ordinary course of business,  (iii) make any loans or advances to any Person
other than loans or advances of  out-of-pocket  expenses  incurred in connection
with the  business  of LaSalle  Holdings  or its  Subsidiaries,  (iv)  pledge or
otherwise  encumber  shares  of  LaSalle  Holdings  or its  Subsidiaries  or (v)
mortgage or pledge any of its material assets, tangible or intangible, or create
any Lien thereupon other than Permitted Liens;

         (d) except  as may be  required  by law  or as  contemplated  by  this
Agreement,  including  Section 5.9, enter into,  adopt or amend or terminate any
bonus, profit sharing, compensation,  severance, termination, change of control,
stock option,  stock  appreciation  right,  restricted stock,  performance unit,
stock  equivalent,  stock  purchase  agreement,  pension,  retirement,  deferred
compensation,   employment,  consulting,  fringe  benefit,  severance  or  other
Employee  Benefit  Plan;  or enter  into or amend any  employment  or  severance
agreement with any director,  officer,  employee or agent of LaSalle Holdings or
any of its  Subsidiaries;  or increase in any manner the salary,  wages,  bonus,
commission or other compensation or benefits of any director,  officer, employee
or  agent  of  LaSalle  Holdings  or  any of its  Subsidiaries,  except,  (i) in
connection  with the  promotion of any director,  officer,  employee or agent of
LaSalle  Holdings  or any of its  Subsidiaries  or  (ii)  for  increases  in the
ordinary  course of business and  consistent  with past  practice for  employees
below the level of Vice  President,  in the aggregate  case not to exceed 5%; or
hire employees at the level of Vice  President or above;  or pay any benefit not
required  by any  plan  and  arrangement  as in  effect  as of the  date  hereof
(including, without limitation, the granting



                                       53
<PAGE>



of stock options, stock appreciation rights or performance units);

         (e) acquire (by merger, amalgamation,  consolidation  or acquisition of
stock or assets or  otherwise)  any  corporation,  partnership,  joint  venture,
association  or other  business  organization  or  division  thereof or make any
material investment either by purchase of stock or securities,  contributions to
capital,  property transfer or acquisition  (including by lease) of any material
amount of properties  or assets of any other Person,  except for the purchase of
investment stock or securities in the ordinary course of business;

         (f)  pay,  discharge or satisfy any claims, liabilities or  obligations
(absolute,  accrued, contingent or otherwise) against LaSalle Holdings or any of
its Subsidiaries,  its directors,  officers, employees or agents, other than the
payment,  discharge  or  satisfaction  in the  ordinary  course of business  and
consistent  with past  practice  of claims for  contractual  benefits  under any
insurance or  reinsurance  contract  under which LaSalle  Holdings or any of its
Subsidiaries or any syndicates managed by any of its Subsidiaries is the insurer
or reinsurer;

         (g)  amend or propose to amend the memorandum of association,  bye-laws
or any similar document of LaSalle Holdings or any of its Subsidiaries;

         (h)  propose to adopt a plan or resolutions providing for the complete
or partial liquidation, dissolution, amalgamation, consolidation, restructuring,
recapitalization  or other  reorganization  of  LaSalle  Holdings  or any of its
Subsidiaries;

         (i) except as set forth in Section  5.2(i) of the  LaSalle  Disclosure
Letter,  enter  into  any new  lines  of  business  (whether  or not part of the
insurance  or  reinsurance  business)  or change  any policy  forms,  investment
policies or  guidelines or otherwise  make material  changes to the operation of
its business or its loss reserve;

         (j) except as set forth in  Section  5.2(j) of the  LaSalle  Disclosure
Letter,  sell (whether by  amalgamation,  consolidation  or  otherwise),  lease,
transfer or dispose of any material assets (including without limitation, rights
of  renewal)  outside  the  ordinary  course of  business  consistent  with past
practice  or enter into any  material  commitment  or  transaction  outside  the
ordinary course of business consistent with past practices;



                                       54
<PAGE>

         (k)  authorize  or make or  commit  to make any  capital  expenditures,
except for transactions in the ordinary course of business  consistent with past
practice (but in no event in excess of $350,000 in the aggregate) or pursuant to
agreements  or  commitments  entered  into  by  LaSalle  Holdings  or any of its
Subsidiaries prior to the date hereof;

         (l)  make any Tax  elections  or settle  or  compromise  any  material
Bermuda,  United  States  federal,  state,  local or other  foreign  income  Tax
liability,  or waive or extend the statute of limitations in respect of any such
Taxes;

         (m)  except as may be  required  as a result of a change in law or in
GAAP, change any of the accounting principles or practices used by it;

         (n)  enter  into  any  agreement  providing  for  the  acceleration of
payment or performance or other consequence as a result of a change in control
of LaSalle Holdings or any of its Subsidiaries;

         (o)  resolve,  commit or agree to take any of the foregoing  actions or
any  action  which  would  make any  representation  or  warranty  in  Article 4
materially untrue or incorrect;

         (p)  make any  material  change in its  retrocessional  agreements  or
arrangements,  including without limitation converting any of its funds withheld
stop loss reinsurance  agreements into another type of reinsurance  agreement or
entering  into  new  funds   withheld  stop  loss   reinsurance   agreements  or
arrangements or stop loss reinsurance  agreements or arrangements that attach at
an attachment point less than the expected loss ratio;

         (q)  make  any  material  change  in  its  reinsurance  agreements  or
arrangements;

         (r) enter into any agreement or arrangement that limits or otherwise
restricts  LaSalle Holdings or any of its Subsidiaries or any successor  thereto
or that could,  after the Effective Time, limit or restrict New Holdings and its
Subsidiaries or any successor thereto, from engaging or competing in any line of
business or in any geographic area; or

         (s)  enter  into  any  new  transaction,   agreement,   arrangement  or
understanding  with any other  Persons that would be required to be disclosed in
the LaSalle SEC Reports  (excluding  the amendment to the CatEPut) in accordance
with Item 404 of Schedule S-K under the Securities Act.

         Nothing in this Section 5.2 shall preclude  LaSalle Holdings or LaSalle
Re from  implementing a new pension plan or amending  existing pension plans, to
comply with Bermuda law.

         Section 5.3    No Solicitation.

         (a)       No Solicitation by Trenwick.




                                       55
<PAGE>



                  (i)  Trenwick  shall  not,  nor  shall  it  permit  any of its
                  Subsidiaries  to, nor shall it  authorize or permit any of its
                  directors,  officers or  employees or any  investment  banker,
                  financial    advisor,    attorney,    accountant    or   other
                  representative  retained by it or any of its  Subsidiaries to,
                  and it shall use  commercially  reasonable  efforts  to ensure
                  that such Persons do not directly or indirectly,  (x) solicit,
                  initiate  or  encourage   (including   by  way  of  furnishing
                  information), or take any other action designed to facilitate,
                  any inquiries or the making of any proposal which  constitutes
                  any  Trenwick  Takeover  Proposal  (as  defined  below) or (y)
                  participate in any discussions or  negotiations  regarding any
                  Trenwick Takeover Proposal; provided, however, that if, at any
                  time the Board of  Directors  of Trenwick  determines  in good
                  faith,  after  consultation  with outside counsel,  that it is
                  necessary  to do so in order  to  comply  with  its  fiduciary
                  duties to the  stockholders of Trenwick under  applicable law,
                  Trenwick may, in response to a Trenwick  Superior Proposal (as
                  defined in Section  5.3(a)(ii))  which was not solicited by it
                  or  which  did not  otherwise  result  from a  breach  of this
                  Section  5.3(a)(i),  and subject to  providing  prior  written
                  notice of its decision to take such action to LaSalle Holdings
                  and   compliance   with  Section   5.3(a)(iii),   (x)  furnish
                  information  with respect to Trenwick and its  Subsidiaries to
                  any Person making a Trenwick  Superior  Proposal pursuant to a
                  customary confidentiality agreement (as determined by Trenwick
                  after   consultation   with  its  outside   counsel)  and  (y)
                  participate  in  discussions  or  negotiations  regarding such
                  Trenwick  Superior  Proposal.  For purposes of this Agreement,
                  "Trenwick  Takeover  Proposal" means any inquiry,  proposal or
                  offer  from any  Person  relating  to any  direct or  indirect
                  acquisition or purchase of a business that  constitutes 15% or
                  more of the net revenues, net income or assets of Trenwick and
                  its  Subsidiaries,  taken  as a  whole,  or 15% or more of any
                  class  of  equity   securities  of  Trenwick  or  any  of  its
                  Subsidiaries,  any  tender  offer or  exchange  offer  that if
                  consummated would result in any Person beneficially owning 15%
                  or more of any class of equity  securities  of Trenwick or any
                  of   its   Subsidiaries,   or   any   merger,   consolidation,
                  amalgamation,    business    combination,    recapitalization,
                  liquidation,  dissolution  or  similar  transaction  involving
                  Trenwick   or  any  of  its   Subsidiaries,   other  than  the
                  transactions  contemplated  by  this  Agreement  or the  Stock
                  Option Agreements.

                  (ii) Except as expressly  permitted  by this  Section  5.3(a),
                  neither the Board of Directors  of Trenwick nor any  committee
                  thereof shall (x) withdraw or modify,  or propose  publicly to
                  withdraw or modify,  in a manner adverse to LaSalle  Holdings,
                  the approval or  recommendation  by such Board of Directors or
                  such  committee  of  this   Agreement  and  the   transactions
                  contemplated  hereby,  (y)  approve or  recommend,  or propose
                  publicly  to  approve  or  recommend,  any  Trenwick  Takeover
                  Proposal,  or (z) cause  Trenwick  to enter into any letter of
                  intent, agreement in principle, acquisition agreement or other
                  similar  agreement (each a "Trenwick  Acquisition  Agreement")
                  related to any Trenwick Takeover Proposal. Notwithstanding the
                  foregoing, the Board of Directors of Trenwick (x) may withdraw
                  or modify its approval and  recommendation  of this  Agreement
                  and the  transactions  contemplated  hereby  if the  Board  of
                  Directors of Trenwick determines



                                       56
<PAGE>



                  in good  faith that it has the  fiduciary  duty to do so under
                  applicable  law and  (y)  may  terminate  this  Agreement  and
                  concurrently with or after such termination, if it so chooses,
                  cause   Trenwick  to  enter  into  any  Trenwick   Acquisition
                  Agreement with respect to any Trenwick Superior Proposal,  but
                  only at a time that is after the fifth  business day following
                  LaSalle  Holdings'  receipt of written notice advising LaSalle
                  Holdings  that the Board of  Directors of Trenwick is prepared
                  to  accept  a  Trenwick  Superior  Proposal,   specifying  the
                  material  terms  and  conditions  of  such  Trenwick  Superior
                  Proposal  and  identifying  the person  making  such  Trenwick
                  Superior Proposal. For purposes of this Agreement, a "Trenwick
                  Superior Proposal" means any proposal made by a third party to
                  acquire,  directly  or  indirectly,  including  pursuant  to a
                  tender offer, exchange offer, merger, consolidation,  business
                  combination,  recapitalization,  liquidation,  dissolution  or
                  similar  transaction,  for  consideration  consisting  of cash
                  and/or securities,  more than 50% of the combined voting power
                  of  the   Trenwick   Shares   then   outstanding   or  all  or
                  substantially  all the assets of  Trenwick  and  otherwise  on
                  terms which the Board of Directors of Trenwick  determines  in
                  its good  faith  judgment  (after  receiving  the  advice of a
                  financial advisor of nationally  recognized  reputation) to be
                  more favorable to Trenwick's  stockholders than this Agreement
                  and  the  transactions   contemplated  hereby  and  for  which
                  financing, to the extent required, is then committed or which,
                  in the  good  faith  judgment  of the  Board of  Directors  of
                  Trenwick,  is  reasonably  capable of being  obtained  by such
                  third party.

                  (iii) In addition to the  obligations of Trenwick set forth in
                  subparagraphs  (a)  (i) and (a)  (ii)  of  this  Section  5.3,
                  Trenwick shall immediately  advise LaSalle Holdings orally and
                  in writing of any request for  information  or of any Trenwick
                  Takeover  Proposal,  the material terms and conditions of such
                  request or Trenwick  Takeover Proposal and the identity of the
                  Person  making  such  request or Trenwick  Takeover  Proposal.
                  Trenwick will keep LaSalle Holdings reasonably informed of the
                  status  and   details   (including   amendments   or  proposed
                  amendments) of any such request or Trenwick Takeover Proposal.

                  (iv) Nothing  contained in this Section 5.3(a) shall  prohibit
                  Trenwick  from taking and  disclosing  to its  stockholders  a
                  position  contemplated by Rule 14e-2(a)  promulgated under the
                  Exchange  Act or from  making  any  disclosure  to  Trenwick's
                  stockholders  if, in the good faith  judgment  of the Board of
                  Directors  of  Trenwick,   after   consultation  with  outside
                  counsel, failure so to disclose would be inconsistent with its
                  obligations under applicable law.

         (b)      No Solicitation by LaSalle Holdings.

                  (i) LaSalle Holdings shall not, nor shall it permit any of its
                  Subsidiaries  to, nor shall it  authorize or permit any of its
                  directors,  officers or  employees or any  investment  banker,
                  financial    advisor,    attorney,    accountant    or   other
                  representative  retained by it or any of its  Subsidiaries to,
                  and it shall use commercially reasonable efforts to ensure
                  that such Persons do not directly or indirectly,  (x) solicit,
                  initiate



                                       57
<PAGE>



                  or encourage (including by way of furnishing information),  or
                  take any other action designed to facilitate, any inquiries or
                  the  making of any  proposal  which  constitutes  any  LaSalle
                  Holdings   Takeover   Proposal  (as  defined   below)  or  (y)
                  participate in any discussions or  negotiations  regarding any
                  LaSalle Holdings Takeover Proposal;  provided,  however,  that
                  if, at any time the Board of  Directors  of  LaSalle  Holdings
                  determines  in good faith,  after  consultation  with  outside
                  counsel, that it is necessary to do so in order to comply with
                  its fiduciary duties to shareholders of LaSalle Holdings under
                  applicable law, LaSalle Holdings may, in response to a LaSalle
                  Holdings Superior Proposal (as defined in Section  5.3(b)(ii))
                  which  was not  solicited  by it or  which  did not  otherwise
                  result from a breach of this Section 5.3(b)(i), and subject to
                  providing  prior  written  notice of its decision to take such
                  action to Trenwick and  compliance  with Section  5.3(b)(iii),
                  (x) furnish  information  with respect to LaSalle Holdings and
                  its  Subsidiaries  to any  Person  making a  LaSalle  Holdings
                  Superior  Proposal  pursuant  to a  customary  confidentiality
                  agreement   (as   determined   by   LaSalle   Holdings   after
                  consultation  with its outside counsel) and (y) participate in
                  discussions or  negotiations  regarding such LaSalle  Holdings
                  Superior  Proposal.  For purposes of this Agreement,  "LaSalle
                  Holdings  Takeover  Proposal"  means any inquiry,  proposal or
                  offer  from any  Person  relating  to any  direct or  indirect
                  acquisition or purchase of a business that  constitutes 15% or
                  more of the net  revenues,  net  income or  assets of  LaSalle
                  Holdings  and its  Subsidiaries,  taken as a whole,  or 15% or
                  more of any class of equity  securities of LaSalle Holdings or
                  any of its  Subsidiaries,  any tender offer or exchange  offer
                  that if  consummated  would result in any person  beneficially
                  owning  15% or more  of any  class  of  equity  securities  of
                  LaSalle  Holdings or any of its  Subsidiaries,  or any merger,
                  consolidation,     amalgamation,     business     combination,
                  recapitalization,    liquidation,   dissolution   or   similar
                  transaction   involving   LaSalle   Holdings  or  any  of  its
                  Subsidiaries, other than the transactions contemplated by this
                  Agreement or the Stock Option Agreements.

                  (ii) Except as  expressly permitted  by this  Section  5.3(b),
                  neither the Board of  Directors  of LaSalle  Holdings  nor any
                  committee  thereof  shall (x)  withdraw or modify,  or propose
                  publicly  to  withdraw  or  modify,  in a  manner  adverse  to
                  Trenwick,  the  approval  or  recommendation  by such Board of
                  Directors  or  such   committee  of  this  Agreement  and  the
                  transactions contemplated hereby, (y) approve or recommend, or
                  propose publicly to approve or recommend, any LaSalle Holdings
                  Takeover Proposal, or (z) cause LaSalle Holdings to enter into
                  any  letter of intent,  agreement  in  principle,  acquisition
                  agreement or other similar agreement (each a "LaSalle Holdings
                  Acquisition   Agreement")  related  to  any  LaSalle  Holdings
                  Takeover Proposal. Notwithstanding the foregoing, the Board of
                  Directors  of LaSalle  Holdings (x) may withdraw or modify its
                  approval  and   recommendation   of  this  Agreement  and  the
                  transactions  contemplated hereby if the Board of Directors of
                  LaSalle  Holdings  determines  in good  faith  that it has the
                  fiduciary  duty  to do so  under  applicable  law  and (y) may
                  terminate this Agreement and  concurrently  with or after such
                  termination, if it so chooses, cause LaSalle Holdings to enter
                  into any LaSalle Holdings Acquisition Agreement with respect



                                       58
<PAGE>



                  to any LaSalle Holdings Superior Proposal,  but only at a time
                  that is after  the fifth  business  day  following  Trenwick's
                  receipt of written notice advising  Trenwick that the Board of
                  Directors of LaSalle  Holdings is prepared to accept a LaSalle
                  Holdings Superior Proposal,  specifying the material terms and
                  conditions  of such  LaSalle  Holdings  Superior  Proposal and
                  identifying the person making such LaSalle  Holdings  Superior
                  Proposal.  For purposes of this Agreement, a "LaSalle Holdings
                  Superior Proposal" means any proposal made by a third party to
                  acquire,  directly  or  indirectly,  including  pursuant  to a
                  tender   offer,   exchange   offer,   merger,   consolidation,
                  amalgamation,    business    combination,    recapitalization,
                  liquidation,   dissolution   or   similar   transaction,   for
                  consideration consisting of cash and/or securities,  more than
                  50% of the combined  voting power of LaSalle  Holdings  Shares
                  then  outstanding  or all or  substantially  all the assets of
                  LaSalle  Holdings  and  otherwise  on terms which the Board of
                  Directors  of LaSalle  Holdings  determines  in its good faith
                  judgment (after receiving the advice of a financial advisor of
                  nationally  recognized  reputation)  to be more  favorable  to
                  LaSalle  Holdings'  stockholders  than this  Agreement and the
                  transactions  contemplated hereby and for which financing,  to
                  the extent  required,  is then committed or which, in the good
                  faith judgment of the Board of Directors of LaSalle  Holdings,
                  is reasonably capable of being obtained by such third party.

                  (iii) In addition to the  obligations of LaSalle  Holdings set
                  forth in subparagraphs (b)(i) and (b)(ii) of this Section 5.3,
                  LaSalle Holdings shall immediately  advise Trenwick orally and
                  in writing of any  request for  information  or of any LaSalle
                  Holdings Takeover Proposal,  the material terms and conditions
                  of such request or LaSalle Holdings  Takeover Proposal and the
                  identity of the person making such request or LaSalle Holdings
                  Takeover   Proposal.   LaSalle  Holdings  will  keep  Trenwick
                  reasonably  informed  of the  status  and  details  (including
                  amendments  or  proposed  amendments)  of any such  request or
                  LaSalle Holdings Takeover Proposal.

                  (iv) Nothing  contained in this Section 5.3(b) shall  prohibit
                  LaSalle   Holdings   from   taking  and   disclosing   to  its
                  stockholders   a  position   contemplated   by  Rule  14e-2(a)
                  promulgated   under  the  Exchange  Act  or  from  making  any
                  disclosure to LaSalle  Holdings'  shareholders if, in the good
                  faith judgment of the Board of Directors of LaSalle  Holdings,
                  after  consultation  with  outside  counsel,   failure  so  to
                  disclose  would be  inconsistent  with its  obligations  under
                  applicable law.

         Section 5.4   Access  to  Information;  Confidentiality.  Between  the
date of this  Agreement and the  Effective  Time,  each of LaSalle  Holdings and
Trenwick shall,  and shall cause each of its respective  Subsidiaries to, afford
the other  party  and its  officer,  employees  and  authorized  representatives
(including,  without  limitation,  attorneys,  auditors,  financial advisors and
actuaries) of the other  reasonable  access during normal  business hours during
the period prior to the Effective Time to all its  personnel,  offices and other
facilities  and to its books and  records  and will  permit  such  party and its
authorized  representatives  to  make  such  inspections  of its  financial  and
operating data and other information with respect to its business and properties
as such party and



                                       59

<PAGE>



its authorized  representatives  may from time to time  reasonably  request.  No
information or knowledge obtained in any investigation  pursuant to this Section
5.4 shall affect or be deemed to modify any representation or warranty contained
in the  Agreement  or  the  conditions  to the  obligations  of the  parties  to
consummate the Plans. The  confidentiality of all such documents and information
furnished in connection  with the  transactions  contemplated  by this Agreement
shall be governed by the terms of the Confidentiality Letter.

         Section 5.5  Form S-4; Regulatory  Matters. As soon as is reasonably
practicable following the date of this Agreement,  LaSalle Holdings and Trenwick
shall  prepare  and file  with the SEC,  pursuant  to Rule  14a-6(a)  under  the
Exchange  Act, the Joint Proxy  Statement  and a  registration  statement of New
Holdings  on Form S-4 with  respect  to the  transactions  contemplated  by this
Agreement.  LaSalle  Holdings and Trenwick  shall cause New Holdings to file the
Form S-4 promptly  after the  conclusion  of the SEC's review of the Joint Proxy
Statement.  Each of LaSalle  Holdings  and  Trenwick  shall  provide  reasonable
opportunity  for the other to review and comment  upon the contents of the Joint
Proxy Statement and the Form S-4 and shall not include therein or omit therefrom
any  information  or supplement  to which counsel to the other shall  reasonably
object  or  specifically  request  (as the case may be).  After  the date of the
mailing of the Joint Proxy  Statement,  each of LaSalle  Holdings  and  Trenwick
agrees  promptly  to  notify  the  other of and to  correct  or  supplement  any
information which either of them shall have furnished for inclusion in the Joint
Proxy  Statement  that shall have become  false or  misleading  in any  material
respect.  Trenwick and LaSalle  Holdings shall use all  commercially  reasonable
efforts to have the Joint Proxy Statement  cleared by the SEC under the Exchange
Act and the Form S-4 declared  effective under the Securities Act as promptly as
practicable  after such filing.  New Holdings  shall also take any action (other
than  qualifying  to do business in any  jurisdiction  in which it is not now so
qualified  or to file a general  consent to service of  process)  required to be
taken under any  applicable  state  securities and "Blue Sky" laws in connection
with the issue of New Holdings  Shares in accordance with the Plans and upon the
exercise  of New  Holdings  Options  (as  defined  herein)  and each of  LaSalle
Holdings and Trenwick shall furnish all  information  concerning  itself and its
shareholders as may reasonably be requested in connection with any such action.

         Section 5.6  Public Announcements. LaSalle Holdings and Trenwick shall
not issue any press release or otherwise make any public statements with respect
to the Plans,  this Agreement or the  transactions  contemplated  hereby without
first  consulting  with each other,  and providing each other the opportunity to
review,  comment  upon and concur as to the  wording,  timing and media for such
press release or statement,  except for any press release or statement as may be
required by  applicable  law,  court process or the  obligation  pursuant to any
listing statement with any national  securities  exchange,  in which case notice
shall be given to the other party prior to the issuance of such press release or
the dissemination of such written  material.  The parties agree that the initial
press release to be issued with respect to the transactions contemplated by this
Agreement, the Plans and the Stock Option Agreements shall be in the form hereto
agreed by the parties.



                                       60
<PAGE>

         Section 5.7  Supplemental  Information.  Prior to the Effective Time,
each party will  promptly  disclose  in writing to the other  parties any matter
hereafter  arising  which,  if existing,  occurring or known at the date of this
Agreement  would have been required to be disclosed to such other parties.  Each
party shall promptly  advise the other parties of such party's  knowledge of any
Material  Adverse  Effect.  Except where  prohibited by applicable  statutes and
regulations,  each party shall promptly  provide the other (or its counsel) with
copies of all filings,  material notices or material communications made by such
party with any Governmental  Authority (including the SEC or NYSE) in connection
with  this  Agreement  or the  Stock  Option  Agreements,  or  the  transactions
contemplated hereby or thereby.  No information  provided to a party pursuant to
this Section 5.7 shall be deemed to cure any breach of any  representation of or
warranty made in this  Agreement  unless the party  receiving  such  information
specifically agrees thereto in writing.

         Section 5.8  Shareholders'  Meetings.  LaSalle Holdings and LaSalle Re
shall  each  request  the Court to convene a special  meeting of its  respective
shareholders (and, if necessary,  classes of shareholders),  with the meeting of
LaSalle  Holdings to occur  first,  and  Trenwick,  acting  through its Board of
Directors,  shall  in  accordance  with the GCL call a  special  meeting  of its
stockholders (and, if necessary, classes of stockholders), and shall give notice
of,  convene and hold such special  meetings as soon as  practicable,  but in no
event more than 45 days, after the Form S-4 is declared effective by the SEC for
the purpose of approving this Agreement and all actions  contemplated hereby. In
connection with such meetings, each of LaSalle Holdings, LaSalle Re and Trenwick
shall mail the Joint Proxy Statement to its respective  shareholders as promptly
as practicable.  The respective Boards of Directors of each of LaSalle Holdings,
LaSalle Re and Trenwick shall submit for approval and adoption by its respective
shareholders the matters to be voted upon at such meetings and shall, subject to
their fiduciary  duties after having consulted with and considered the advice of
outside counsel,  include in the Joint Proxy Statement the recommendation of its
respective  Board  of  Directors  that  the  shareholders  vote in  favor of the
approval and adoption of this  Agreement and the Plans and each such party shall
(subject to the fiduciary duties of its Board of Directors) use all commercially
reasonable  efforts to secure such  approval  and  adoption.  LaSalle  Holdings,
LaSalle Re and  Trenwick  shall  coordinate  and  cooperate  with respect to the
timing of such  meetings  and shall  endeavor to hold such  meetings on the same
day.

        Section 5.9  Trenwick Options,  LaSalle Holdings Options,  LaSalle Re
Options and Trenwick Warrants.

         (a)      Trenwick Options.

                  (i) At the Effective  Time, each  outstanding  Trenwick Option
                  shall be  replaced by an option (a "New  Holdings  Option") to
                  acquire New  Holdings  Shares,  the terms of which shall be no
                  less  favorable  than the terms  currently  applicable to such
                  Trenwick  Option,   under  a  new  stock  option  plan  to  be
                  established  by New  Holdings  for such  purposes  before  the
                  Closing Date (the "New Holdings Option Plan"), all as provided
                  in Section 5.9(a)(ii).




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<PAGE>

                  (ii) The cancellation of Trenwick Options and replacement with
                  New Holdings  Options shall comply in all respects  with,  and
                  shall  be  performed  in  accordance   with,  the  methodology
                  prescribed by the provisions of Section 424(a) of the Code and
                  the regulations  thereunder and each New Holdings Option shall
                  provide the option holder with termination  rights that are no
                  less favorable to such holder than
                  were  provided  under  the  Trenwick  Option  for which it was
                  replaced as of the  Effective  Time.  The parties  contemplate
                  that,  consistent with the  methodology  prescribed by Section
                  424(a) of the Code and the applicable  regulations  thereunder
                  (A) the  number of New  Holdings  Shares  subject  to such New
                  Holdings  Option will be determined by multiplying  the number
                  of Trenwick Shares subject to Trenwick Options by the Trenwick
                  Exchange  Ratio  (rounded to the next higher whole number with
                  respect to each holder  thereof)  and (B) the  exercise  price
                  under such New Holdings  Option will be determined by dividing
                  the  exercise  price per share  under the  Trenwick  Option in
                  effect  immediately  prior to the Merger Effective Time by the
                  Trenwick  Exchange  Ratio and rounding the exercise price thus
                  determined  to the nearest  whole cent (a  half-cent  shall be
                  rounded to the next higher whole cent).

                  (iii) As promptly as practicable after the Effective Time, New
                  Holdings shall issue to each holder of an outstanding Trenwick
                  Option a document  evidencing  the New Holdings  Option having
                  the terms  provided  for in  Sections  5.9(a)(i)  and (ii) and
                  effective as of the Effective Time.

         (b)      LaSalle Holdings Options.

                  (i) At the Effective Time, each  outstanding  LaSalle Holdings
                  Option shall be replaced by a New Holdings  Option,  the terms
                  of which shall be no less favorable  than the terms  currently
                  applicable  to such  LaSalle  Holdings  Option,  under the New
                  Holdings Option Plan, all as provided in Section 5.9(b)(ii).

                  (ii)  The   cancellation  of  LaSalle  Holdings  Options  and
                  replacement  with New  Holdings  Options  shall  comply in all
                  respects with, and shall be performed in accordance  with, the
                  methodology  prescribed by the provisions of Section 424(a) of
                  the Code and the regulations  thereunder and each New Holdings
                  Option shall provide the option holder with termination rights
                  that are no less  favorable to such holder than were  provided
                  under the LaSalle Holdings Option for which it was replaced as
                  of  the  Effective   Time.  The  parties   contemplate   that,
                  consistent with the  methodology  prescribed by Section 424(a)
                  of the Code and the applicable  regulations thereunder (A) the
                  number of New  Holdings  Shares  subject to such New  Holdings
                  Option will be determined by multiplying the number of LaSalle
                  Holdings  Shares  subject to LaSalle  Holdings  Options by the
                  LaSalle  Exchange  Ratio  (rounded  to the next  higher  whole
                  number  with  respect  to  each  holder  thereof)  and (B) the
                  exercise  price  under  such  New  Holdings   Option  will  be
                  determined by dividing the exercise  price per share under the
                  LaSalle  Holdings  Option in effect  immediately  prior to the
                  Scheme  Effective  Time  by the  LaSalle  Exchange  Ratio  and
                  rounding the  exercise  price thus  determined  to the nearest
                  whole cent (a  half-cent  shall be rounded to the next  higher
                  whole cent).



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<PAGE>

                  (iii) As promptly as practicable after the Effective Time, New
                  Holdings shall issue to each holder of an outstanding  LaSalle
                  Holdings Option a document evidencing the New Holdings Option
                  having the terms provided for in Sections  5.9(b)(i) and (ii)
                  and  effective  as of the Effective Time.

         (c)      LaSalle Re Options.

                  (i)  Pursuant  to Section  2(H) of that  certain  Amended  and
                  Restated  Option  Agreement  dated  November  27,  1995  among
                  LaSalle  Holdings,  LaSalle  Re and each of the  optionholders
                  listed on  Schedule  I  thereto,  from and  after  the  Scheme
                  Effective  Time,  each  holder  of an  outstanding  option  to
                  acquire  Non-Voting Shares shall be entitled,  upon payment of
                  the  exercise  price  thereof,  to receive,  at such  holder's
                  election,  either (i) the number of Non-Voting  Shares covered
                  by such option or (ii) the number of New Holdings  Shares that
                  such holder  would have  received  pursuant to Section  2.6(a)
                  (plus, if applicable,  the amount of cash payable in lieu of a
                  fractional share that such holder would have received pursuant
                  to Section  2.12) if such  holder had  exercised  such  option
                  immediately  prior to the Scheme  Effective  Time.  LaSalle Re
                  undertakes to use  commercially  reasonable  efforts to obtain
                  the  consent  of each of the  holders  of such  options to the
                  cancellation of such options and replacement  thereof with New
                  Holdings  Options,  the  terms  of  which  shall  be  no  less
                  favorable than the terms currently applicable to such options.

                  (ii)  Pursuant  to  Section   2(F)  of  that   certain   Stock
                  Appreciation  Rights  Agreement  dated  as of  April  1,  1994
                  between  Victor H.  Blake and  LaSalle  Re, if Victor H. Blake
                  exercises  any of his stock  appreciation  rights  during  the
                  period  beginning at the Scheme  Effective  Time and ending on
                  November 22, 2003,  he shall be entitled to receive the number
                  of New Holdings Shares that he would have received pursuant to
                  Section  2.6(a)  (plus,  if  applicable,  the  amount  of cash
                  payable  in lieu of a  fractional  share  that he  would  have
                  received  pursuant to Section 2.12) if he had  exercised  such
                  stock  appreciation  rights  immediately  prior to the  Scheme
                  Effective Time.

         (d)  Registration  of  Options.  If the  New  Holdings  Options  issued
pursuant to Sections 5.9(a), (b) and (c) are not already covered by an effective
registration  statement,  New  Holdings  will file a  registration  statement as
promptly as practicable after the Effective Time, which  registration  statement
will cover the New Holdings  Shares  issuable  upon exercise of the New Holdings
Options granted in substitution of Trenwick  Options,  LaSalle  Holdings Options
and LaSalle Re Options,  and New Holdings will use all  commercially  reasonable
efforts to cause  such  registration  statement  to become  effective  under the
Securities Act and to maintain such  registration  statement in effect until the
exercise or termination of all such New Holdings Options.



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<PAGE>

         (e) Trenwick  Warrants. At the Effective  Time,  each then  outstanding
warrant of  Trenwick  shall be assumed by New  Holdings in  accordance  with its
terms.

         Section 5.10   Takeover Laws. The parties shall use all commercially
reasonable  efforts to exempt the  transactions  contemplated  by this Agreement
from,  and otherwise act to eliminate or minimize the effects of any  applicable
takeover or change of control law.

         Section 5.11   Affiliates.

         (a) At least  five  days  prior to the  Closing  Date,  Trenwick  shall
deliver to LaSalle Holdings a letter identifying all persons who are anticipated
to be,  at the  time  of the  Trenwick  stockholders  meeting,  "affiliates"  of
Trenwick  for  purposes  of Rule 145  under the  Securities  Act  ("Rule  145").
Trenwick shall furnish such  information  and documents as LaSalle  Holdings may
reasonably request for the purpose of reviewing such letter.  Trenwick shall use
all commercially reasonable efforts to cause each Person who is identified as an
"affiliate" in such letter to deliver to LaSalle Holdings,  prior to the Closing
Date, a written  agreement in connection with  restrictions on affiliates  under
Rule 145, in a form mutually agreeable to Trenwick and LaSalle Holdings.

         (b) At least  five days prior to the  Closing  Date,  LaSalle  Holdings
shall deliver to Trenwick a letter  identifying  all Persons who are anticipated
to be, at the time of the LaSalle Holdings shareholders meeting, "affiliates" of
LaSalle  Holdings for purposes of Rule 145.  LaSalle Holdings shall furnish such
information and documents as Trenwick may reasonably  request for the purpose of
reviewing such letter.  LaSalle Holdings shall use all  commercially  reasonable
efforts to cause each Person who is identified as an  "affiliate" in such letter
to deliver to  Trenwick,  prior to the  Closing  Date,  a written  agreement  in
connection with  restrictions  on affiliates  under Rule 145, in a form mutually
agreeable to Trenwick and LaSalle Holdings.

         Section 5.12  Stock Exchange Listing.  Trenwick, LaSalle Holdings and
New  Holdings  shall use all  commercially  reasonable  efforts to cause the New
Holdings  Shares to be issued in accordance  with the Plans and the New Holdings
Shares to be  reserved  for issue upon  exercise of New  Holdings  Options to be
approved for listing on the NYSE, subject to official notice of issuance,  prior
to the Closing Date.

         Section 5.13  Indemnification and Insurance.

         (a) From and after the Effective  Time, New Holdings  shall  indemnify,
defend and hold  harmless  each  Person who is, or has been at any time prior to
the date  hereof or who  becomes  prior to the  Effective  Time,  an  officer or
director of Trenwick and LaSalle Holdings (the  "Indemnified  Parties")  against
all  losses,  expenses,  claims,  damages  and  liabilities  arising  out of the
transactions  contemplated by this Agreement to the fullest extent  permitted or
required  under  applicable  law  (including,  without  limitation,   reasonable
attorneys' fees).  Subject to any limitations  imposed by Bermuda law and public
policy,  to the  extent  applicable,  New  Holdings  agrees  that all  rights to
indemnification  existing in favor of current and former  directors and officers
of  Trenwick,  LaSalle  Holdings  or any of  their  respective  Subsidiaries  as
provided  in such  corporation's  certificate  of  incorporation  or by-laws (or
analogous documents) or existing indemnification  agreements, as in effect as of
the date hereof,  with respect to matters  occurring through the Effective Time,
shall  survive the Plans and shall  continue  in full force and effect,  and New
Holdings shall  guarantee the  obligations  of Trenwick and LaSalle  Holdings in
respect thereof; provided, however, that this shall not limit the ability of New
Holdings to effect any corporate restructuring of its Subsidiaries.



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<PAGE>


         (b) New Holdings  shall cause to be maintained for a period of not less
than six years from the Effective Time the  directors'  and officers'  insurance
and, fiduciary liability insurance indemnification policies currently maintained
by Trenwick  and  LaSalle  Holdings  to the extent  that such  policies  provide
coverage for events  occurring prior to the Effective Time (the "D&O Insurance")
for any of the Indemnified  Parties so long as the annual premium therefor would
not be in excess of two hundred  percent  (200%) of the last annual premium paid
prior to the date of this Agreement (two hundred percent (200%) of such premium,
the "Maximum  Premium");  provided,  however,  that New Holdings may, in lieu of
maintaining  such  existing  D&O  Insurance  as  provided  above,  cause no less
favorable coverage to be provided under any policy maintained for the benefit of
the  directors  and  officers  of  Trenwick,  LaSalle  Holdings  or any of their
respective  Subsidiaries,  so long as (i) the insurance  company  providing such
coverage  thereof has an A.M.  Best  Company  rating of A or better and (ii) the
material terms thereof are no less advantageous to the Indemnified  Parties than
the existing D&O Insurance. If the existing D&O Insurance expires, is terminated
or  cancelled  or if the  premium  for such D&O  Insurance  exceeds  the Maximum
Premium during such six-year period, New Holdings will cause to be obtained,  to
the extent commercially available,  replacement D&O Insurance as can be obtained
for the  remainder  of such  six-year  period for a premium not in excess of the
Maximum Premium on terms and conditions no less  advantageous to the Indemnified
Parties than the existing D&O Insurance.

         (c) The  provisions  of  Section  5.13 are in  addition  to, and not in
substitution  for any  rights  that an  Indemnified  Party  may have  under  the
applicable certificate of incorporation,  memorandum of association, or by-laws,
bye-laws  or  agreements  with  Trenwick  and  LaSalle  Holdings or any of their
respective  Subsidiaries or under applicable law. New Holdings agrees to pay all
costs and expenses (including fees and expenses of counsel) that may be incurred
by an  Indemnified  Party  in  successfully  enforcing  the  indemnity  or other
obligations  under this Section 5.13.  The provisions of this Section 5.13 shall
survive  the  Closing  and are  intended  for  the  benefit  of,  and  shall  be
enforceable  by,  each  of  the  Indemnified  Parties,  their  heirs  and  their
representatives.

         Section 5.14  Commercially  Reasonable Efforts.  Upon the terms and
subject to the conditions and other agreements set forth in this Agreement, each
of the parties hereto will use commercially reasonable efforts to take, or cause
to be  taken,  all  actions  and to do, or cause to be done,  and to assist  and
cooperate  with the other  parties  in doing,  all things  necessary,  proper or
advisable to  consummate  and make  effective,  in the most  expeditious  manner
possible,  the  transactions  contemplated  by this  Agreement  (including  with
respect to Trenwick,  the reduction of any taxation of Trenwick arising from the
Plan of Reorganization) and shall use all commercially




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<PAGE>

reasonable efforts to obtain all waivers, permits, consents and approvals and to
effect  all  registrations,  filings  and  notices  with or to third  parties or
Governmental Authorities which are necessary or desirable in connection with the
transactions contemplated by this Agreement. If, at any time after the Effective
Time any further  action is  necessary or desirable to carry out the purposes of
this  Agreement,  the proper officers or directors of each of the parties hereto
shall take such action.

         Section 5.15   Post-Closing Matters.

         (a) LaSalle  Holdings,  Trenwick and their respective  Affiliates shall
(and,  following the  Effective  Time,  New Holdings  shall) take no action with
respect to the stock,  assets or  liabilities  of LaSalle  Holdings or Trenwick,
including,  without limitation, the filing of Tax returns or reports, that would
be inconsistent  with the  qualification  of the Plans as tax-free under Section
351 of the Code; provided,  however,  that Trenwick,  LaSalle Holdings and their
respective Affiliates may file with the appropriate Governmental Authorities and
execute all documents  necessary to consummate the Plans and other  transactions
contemplated by this Agreement.

         (b) Upon  request,  New  Holdings  shall  use  commercially  reasonable
efforts to  cooperate  with any LaSalle  Holdings  shareholder  or any  Trenwick
stockholder in the completion and administration of a gain recognition agreement
under Section 367 of the Code.

         Section 5.16  Employee Benefit Plans; Existing Agreements.

         (a) For a period of at least one year  after the  Effective  Time,  New
Holdings will cause (i) the employees of Trenwick and its  Subsidiaries  who are
employed  immediately  after the Effective  Time  ("Trenwick  Employees")  to be
provided with employee  benefits under Employee  Benefit Plans maintained by New
Holdings  ("New  Holdings  Plans") which are no less  favorable in the aggregate
than benefits provided to Trenwick Employees  immediately prior to the Effective
Time; and (ii) the employees of LaSalle  Holdings and its  Subsidiaries  who are
employed  immediately after the Effective Time ("LaSalle Holdings Employees") to
be provided with  employee  benefits  under the New Holdings  Plans which are no
less  favorable in the  aggregate  than  benefits  provided to LaSalle  Holdings
Employees immediately prior to the Effective Time, except for the termination of
the LaSalle Re Holdings Limited Employee Stock Purchase Plan.

         (b) With respect to each New Holdings Plan, for purposes of determining
eligibility to participate,  vesting and entitlement to benefits,  including for
severance  benefits  and  vacation  entitlement  (but not for accrual of pension
benefits  except to the extent that past service credit is provided in a similar
manner to both Trenwick Employees and LaSalle Holdings Employees),  service with
Trenwick and its Subsidiaries by Trenwick Employees  employed  immediately after
the Merger  Effective  Time shall be treated as service  with New  Holdings  and
service with LaSalle Holdings and its Subsidiaries by LaSalle Holdings Employees
employed immediately after the Scheme Effective Time shall be treated as service
with New Holdings;  provided, however, that such service shall not be recognized
to the extent that such  recognition  would result in a duplication of benefits.
Such service also shall apply for purposes of  satisfying  any waiting  periods,
evidence of  insurability  requirements  or the  application of any  preexisting
condition



                                       66
<PAGE>



limitations.  Trenwick  Employees and LaSalle Holdings  Employees shall be given
credit for  amounts  paid under a  corresponding  benefit  plan  during the same
period for  purposes  of  applying  deductibles,  copayments  and  out-of-pocket
maximums as though such amounts had been paid in  accordance  with the terms and
conditions of the New Holdings Plan.

         (c) Except  with  respect  to those  plans and  arrangements  listed in
Section 5.16 of the Trenwick  Disclosure Letter or the LaSalle Disclosure Letter
(as  applicable),  following the  Effective  Time,  New Holdings  shall honor in
accordance with their terms (i) all employment, severance and other compensation
agreements  and  arrangements  existing  on or  prior to the  execution  of this
Agreement  which are  between  Trenwick  and any  director,  officer or employee
thereof and which have been disclosed in Section 3.16 of the Trenwick Disclosure
Letter and  previously  have been  delivered  to LaSalle  Holdings  and (ii) all
employment,   severance  and  other  compensation  agreements  and  arrangements
existing  on or prior to the  execution  of this  Agreement  which  are  between
LaSalle  Holdings and any director,  officer or employee  thereof and which have
been  disclosed  in  Section  4.16(a)  of  the  LaSalle  Disclosure  Letter  and
previously have been delivered to Trenwick.

         (d) It is understood and agreed between the parties that all provisions
contained in this Agreement  with respect to employee  benefit plans or employee
compensation are included for the sole benefit of the respective  parties hereto
and do not and shall not create any right in any other  person,  including,  but
not limited to, any LaSalle  Holdings  Employee or any  Trenwick  Employee,  any
participant in any benefit or compensation plan or any beneficiary thereof.

         Section 5.17    Letters from Accountants.

         (a) LaSalle Holdings shall use all commercially  reasonable  efforts to
cause to be delivered  to Trenwick  two letters from  Deloitte & Touche LLP, its
independent public accountants, one dated a date within two business days before
the date on which  the Form S-4  shall  become  effective  and one  dated a date
within two business days before the Effective  Date, each addressed to Trenwick,
in form and  substance  reasonably  satisfactory  to Trenwick and  comparable in
scope and  substance to comfort  letters  customarily  delivered by  independent
public  accountants in connection with  registration  statements  similar to the
Form S-4 and transactions such as those contemplated by this Agreement.

         (b)  Trenwick  shall use its best  efforts to cause to be  delivered to
LaSalle  Holdings two letters of  PricewaterhouseCoopers  LLP,  its  independent
public accountants, one dated a date within two business days before the date on
which the Form S-4  shall  become  effective  and one  dated a date  within  two
business days before the Effective Date, each addressed to LaSalle Holdings,  in
form and substance reasonably satisfactory to LaSalle Holdings and comparable in
scope and  substance to comfort  letters  customarily  delivered by  independent
public  accountants in connection with  registration  statements  similar to the
Form S-4 and transactions such as those contemplated by this Agreement.




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<PAGE>

         Section 5.18   Litigation.  Each of Trenwick  and LaSalle  Holdings
shall (to the extent their interests do not diverge) cooperate in the defense of
any litigation  against  Trenwick or LaSalle  Holdings,  as applicable,  and its
directors  and  officers  relating  to the  transactions  contemplated  by  this
Agreement, the Plans and the Stock Option Agreements.

         Section 5.19  Advice of Changes. Each of Trenwick and LaSalle Holdings
agrees  that  it  shall  give  the  other  party   prompt   notice  of  (i)  any
representation  or  warranty  made by it  contained  in this  Agreement  that is
qualified as to materiality  becoming untrue or inaccurate in any respect or any
such  representation  or warranty  that is not so qualified  becoming  untrue or
inaccurate  in any material  respect or (ii) the failure by it to comply with or
satisfy in any  material  respect any  covenant,  condition  or  agreement to be
complied with or satisfied by it under this Agreement;  provided,  however, that
no such notification shall affect the representations,  warranties, covenants or
agreements of the parties or the  conditions to the  obligations  of the parties
under this Agreement.

         Section 5.20 Trenwick Rights Agreement.  The Board of Directors of
Trenwick  shall take all  further  action (in  addition  to that  referred to in
Section 3.20)  reasonably  requested in writing by LaSalle  Holdings in order to
render the Trenwick Rights  inapplicable  to  transactions  contemplated by this
Agreement,  the Plans and the Stock  Option  Agreements  to the extent  provided
herein and in the Trenwick Rights Plan amendment.

         Section 5.21  New  Holdings  Rights  Agreement.  The  Board of
Directors  of New  Holdings  shall  take all action  necessary  to  implement  a
shareholders  rights plan (the "New Holdings Rights  Agreement"),  substantially
similar  to the  Trenwick  Rights  Agreement  and  Trenwick  Rights,  except  as
otherwise  contemplated by Section 5.21 of the Trenwick  Disclosure Letter or as
otherwise  agreed by Trenwick and LaSalle  Holdings,  with such other changes as
are set forth on Section 5.21 of the Trenwick Disclosure Letter and such changes
therein as may be agreed by Trenwick and LaSalle  Holdings,  effective as of the
Effective Time.

         Section 5.22  Organization of Trenwick  Subsidiaries.  During the
period from the date of this  Agreement to the Effective  Time,  Trenwick  shall
organize  Trenwick  LLC and  Trenwick  Subsidiary  and  shall  cause  each  such
Subsidiary to enter into the  transactions  described in Section  2.1(b) of this
Agreement  by  executing  a joinder  hereto,  subject to  obtaining  stockholder
approval pursuant to Section 264 and Section 271 of the GCL.

         Section 5.23  Assumption of Non-Voting Share Conversion  Obligation.
In the event that the Scheme of Arrangement is not approved by the holders of at
least  seventy-five  percent  (75%) of the  issued  and  outstanding  Non-Voting
Shares,  then,  prior to the  consummation  of the  Scheme of  Arrangement  with
respect to the LaSalle  Holdings  Shares,  New Holdings  shall assume by written
instrument the obligation to deliver one New Holdings Share in exchange for each
Non-Voting Share  surrendered for exchange  pursuant to that certain  Conversion
Agreement dated as of November 27, 1995 among LaSalle  Holdings,  LaSalle Re and
each of the Persons listed on Schedule I thereto.




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<PAGE>

        Section 5.24 Assumption of Series B Preferred Share Conversion
Obligation.  Prior to the Scheme  Effective  Time,  New Holdings shall assume by
written  instrument  the  obligation  to deliver to the  holders of any Series B
Preferred  Shares,  par value $1.00 per share,  of LaSalle  Holdings  ("Series B
Preferred Shares"),  upon the basis and upon the terms and conditions  specified
in the  Certificate  of  Designation,  Preferences  and  Rights of the  Series B
Preferred  Shares  with  respect to the  conversion  of such  Series B Preferred
Shares,  and in lieu of the  LaSalle  Holdings  Shares  immediately  theretofore
receivable upon such conversion,  such shares of stock,  securities or assets as
may be issued or payable  with respect to or in exchange for a number of LaSalle
Holdings  Shares  equal to the number of  LaSalle  Holdings  Shares  immediately
theretofore so receivable had the Scheme of Arrangement not been consummated.

          Section 5.25 Tax-Free Reorganization. Trenwick, New Holdings and
LaSalle Holdings shall each use its best efforts to cause the exchange described
in  Section  2.1(c) to be  treated as a  reorganization  within  the  meaning of
Section  368(a) of the Code and to cause the Scheme of Arrangement to be treated
as  tax-free  under  Section  351 of the Code and to cause the  delivery  of the
certificates  of  officers  and  opinions  upon  which the  opinions  of Baker &
McKenzie under Section  6.1(h),  Section 6.2(g) and Section 6.3(h) will rely and
upon which the opinion of Mayer, Brown & Platt under Section 6.1(g) will rely.

                                    ARTICLE 6

                             CONDITIONS TO THE PLANS

         Section 6.1  Conditions  to Each  Party's  Obligation  to Effect the
Plans. The respective  obligations of each party to this Agreement to consummate
the Plans and to effect  the  actions  referred  to in Section  2.2(c)  shall be
subject to the following conditions:

         (a)   Stockholder  Approvals. This  Agreement, the  Plans and the other
transactions  contemplated  hereby  shall have been  approved and adopted by any
requisite vote or consent of (i) the relevant classes of Trenwick's stockholders
as required by the GCL, Trenwick's  certificate of incorporation and by-laws and
(if  applicable),  the NYSE and (ii) the relevant  classes of LaSalle  Holdings'
shareholders  as required by the Companies Act and (if  applicable) the NYSE and
LaSalle  Holdings'  bye-laws,  and orders of the Court sanctioning the Scheme of
Arrangement shall have been obtained.

         (b)   Third Party Consents.

                  (i) Both of Trenwick and LaSalle  Holdings shall have received
                  all  consents and  approvals  required by any lender or equity
                  provider  as  further  set  forth  in  Section  6.1(b)  of the
                  Trenwick  Disclosure Letter and the LaSalle Disclosure Letter,
                  respectively.




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<PAGE>

                  (ii)  Those   regulatory  and  other  approvals   required  to
                  consummate the Plans and the other  transactions  contemplated
                  hereby,  including but not limited to any  applicable  Lloyd's
                  approval and those  approvals  specified in Section 3.8 of the
                  Trenwick  Disclosure  Letter and  Section  4.8 of the  LaSalle
                  Disclosure Letter, shall have been obtained (without any terms
                  or conditions to such approvals which
                  would impose  material and adverse  limitations on the ability
                  of New Holdings and its Subsidiaries to conduct their business
                  after the Effective  Time,  which would require changes to the
                  terms of the Plans which would be material  and adverse to New
                  Holdings,  LaSalle  Holdings or Trenwick or which would change
                  the  consideration  payable to shareholders in accordance with
                  the Plans)  and shall  remain in full force and effect and all
                  statutory  waiting  periods  in  respect  thereof  shall  have
                  expired.

         (c)  No Injunctions or  Restraints.  No order,  decree or injunction of
any court or agency of competent  jurisdiction  shall be in effect,  and no law,
statute  or  regulation  shall  have been  enacted  or  adopted,  that  enjoins,
prohibits or makes illegal consummation of any of the transactions  contemplated
hereby; provided, however, that each of LaSalle Holdings and Trenwick shall have
used all commercially  reasonable efforts to prevent any such rule,  regulation,
injunction,  decree or other  order,  and to appeal as promptly as possible  any
injunction, decree or other order that may be entered.

         (d) Form S-4.  The Form S-4 shall have been  declared  effective by the
SEC and shall not be subject to a stop order or threatened stop order.

         (e) HSR Act. Any waiting period (and any extension  thereof) applicable
to the Plan of Merger under the HSR Act shall have terminated or expired.

         (f) NYSE  Listing.  The New Holdings  Shares to be issued to holders of
Trenwick Shares,  LaSalle Holdings Shares and Minority Shares upon  consummation
of the Plans  shall have been  authorized  for  trading on the NYSE,  subject to
official notice of issuance.

         (g) Mayer,  Brown & Platt Opinion.  New Holdings and LaSalle  Holdings
shall have  received  an opinion of Mayer,  Brown & Platt,  dated the  Effective
Date, on the basis of facts,  representations  and assumptions set forth in such
opinion  that are  consistent  with the facts  existing on the  Effective  Date,
substantially  to the effect that (i) the Scheme of Arrangement  will qualify as
an  exchange  under  Section  351(a) of the  Code,  (ii) no gain or loss will be
recognized by United States transferors of LaSalle Holdings Shares who, actually
or  constructively  within the meaning of Section 958 of the Code, own less than
5% of both the  total  voting  power and the  total  value of the  shares of New
Holdings  immediately  after the Plans upon the  receipt of solely New  Holdings
Shares  pursuant  to the  Scheme of  Arrangement,  (iii) no gain or loss will be
recognized by United States transferors of LaSalle Holdings Shares who own 5% or
more of the total  voting  power or the total value of the New  Holdings  Shares
immediately  after the Plans  upon the  receipt of solely  New  Holdings  Shares
pursuant  to the  Scheme  of  Arrangement,  provided  that  such  United  States
transferors enter into gain recognition  agreements  meeting the requirements of
United States Treasury  Regulation  ss.1.367(a)-8,  (iv) no gain or loss will be
recognized by United States  transferors of Non-Voting  Shares who,  actually or
constructively  within the meaning of Section 958 of the Code,  own less than 5%
of both the total voting power and the total value of the shares of New Holdings
immediately  after the Plans  upon the  receipt of solely  New  Holdings  Shares
pursuant  to the  Scheme  of  Arrangement,  and  (v) no  gain  or  loss  will be
recognized  by  United  States  transferors  of  Non-Voting  Shares  who own 5%,
actually or




                                       70
<PAGE>



constructively  within the  meaning of Section  958 of the Code,  or more of the
total  voting power or the total value of the New  Holdings  Shares  immediately
after the Plans upon the receipt of solely New Holdings  Shares  pursuant to the
Scheme of Arrangement,  provided that such United States  transferors enter into
gain recognition  agreements  meeting the requirements of United States Treasury
Regulation 1.367(a)-8.  In rendering such opinion,  counsel may require and rely
upon representations  contained in certificates of officers of LaSalle Holdings,
LaSalle Re, Trenwick, New Holdings, foreign counsel and others.

         (h) Baker & McKenzie  Opinion.  New Holdings  and  Trenwick  shall have
received an opinion of Baker & McKenzie,  dated the Effective Date, on the basis
of facts,  representations  and  assumptions  set forth in such opinion that are
consistent  with the facts existing on the Effective Date  substantially  to the
effect that (i) no gain or loss will be recognized by United States shareholders
of Trenwick upon the receipt of solely New Holdings  Shares pursuant to the Plan
of Reorganization  (except with respect to cash received in lieu of a fractional
share interest in New Holdings Shares), and (ii) the Plan of Reorganization will
qualify as a tax-free  reorganization  within the meaning of Section 368(a).  In
rendering  such  opinion,  counsel  may  require  and rely upon  representations
contained in certificates of officers of LaSalle Holdings,  LaSalle Re, Trenwick
and New Holdings.

         Section 6.2  Additional  Conditions to Trenwick's Obligation to Effect
the Plans.  The obligation of Trenwick to consummate the Plans and to effect the
actions  referred to in Section 2.2(c) shall be further subject to the following
conditions unless waived in accordance with Section 8.3:

         (a)  Performance of Obligations of LaSalle  Holdings. LaSalle  Holdings
shall have performed in all material  respects the  obligations and covenants to
be performed by it at or prior to the Effective Time.

         (b) Representations and Warranties.  The representations and warranties
of  LaSalle  Holdings  contained  in this  Agreement  that are  qualified  as to
materiality shall be true and correct and the  representations and warranties of
LaSalle Holdings  contained in this Agreement that are not so qualified shall be
true and correct in all material  respects,  in each case as of the date of this
Agreement and (except to the extent such representations and warranties speak as
of an  earlier  date) as of the  Closing  Date as  though  made as of and on the
Closing  Date,  except for such  failure or  failures to be true and correct (or
true and correct in all material  respects)  as would not have or be  reasonably
expected to have, individually or in the aggregate, a Material Adverse Effect on
LaSalle Holdings.

         (c)  Compliance  with  Conditions.  Trenwick  shall receive  customary
closing documents in form and substance reasonably satisfactory to it, including
a certificate of an executive officer of LaSalle Holdings certifying  compliance
with the conditions set forth in Sections 6.2(a) and (b).



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<PAGE>


         (d)  Comfort  Letters.  Trenwick  shall have  received  from Deloitte &
Touche LLP the letters described in Section 5.17(a).

         (e)      Consents and Approvals. Trenwick shall have received evidence,
in form and  substance  reasonably  satisfactory  to it, that all  consents  and
approvals  set forth in Section 4.8 of the LaSalle  Disclosure  Letter have been
obtained.

         (f) Fiduciary Duties.  The Board of Directors of LaSalle Holdings shall
not have (A)  withdrawn  or modified or changed in a manner  adverse to Trenwick
its approval or  recommendation of this Agreement in order to approve and permit
LaSalle  Holdings  to  execute  a  definitive  agreement  relating  to a LaSalle
Holdings  Superior  Proposal  (as  defined  in  Section  5.3(b)(ii)),   and  (B)
determined  in good faith,  after  consultation  with outside  legal  counsel to
LaSalle  Holdings  that the  failure  to take  such  action  as set forth in the
preceding  clause  (A) is  reasonably  likely  to  result  in the  breach of the
respective Board of Directors' fiduciary duties under applicable law.

         (g)  Baker & McKenzie  Opinion.  New Holdings and Trenwick  shall have
received an opinion of Baker & McKenzie,  dated the Effective Date, on the basis
of facts,  representations  and  assumptions  set forth in such opinion that are
consistent  with the facts existing on the Effective Date  substantially  to the
effect  that  Trenwick  shall  treat  the Plan of  Reorganization  as a  taxable
disposition of assets directly held by Trenwick,  but that Trenwick shall not be
subject to U.S.  federal  income tax in excess of $60.0  million with respect to
such  gain.  In  rendering  such  opinion,  counsel  may  require  and rely upon
representations  contained  in  certificates  of officers  of LaSalle  Holdings,
LaSalle Re, Trenwick and New Holdings,  including  representations regarding the
adjusted tax basis of the assets of Trenwick.  In  addition,  in rendering  such
opinion,  counsel  may  require and rely upon  opinions  prepared  by  valuation
experts,  including  opinions  regarding  the fair market value of the assets of
Trenwick, foreign counsel and others.

         (h) No Material  Adverse  Change.  At any time after the date of this
Agreement there shall not have occurred any Material  Adverse Change relating to
LaSalle  Holdings;  provided,  that this condition shall no longer be applicable
following the approval of the LaSalle Holdings' shareholders.

         Section 6.3  Additional  Conditions to LaSalle Holdings' Obligation to
Effect the Plans. The obligation of LaSalle Holdings to consummate the Plans and
to effect the actions  referred to in Section 2.2(c) shall be further subject to
the following conditions unless waived in accordance with Section 8.3:

         (a) Performance  of  Obligations  of  Trenwick.   Trenwick  shall  have
performed in all material respects the obligations and covenants to be performed
by it at or prior to the Effective Time.

         (b) Representations and Warranties.  The representations and warranties
of Trenwick  contained in this  Agreement  that are qualified as to  materiality
shall be true and correct and the  representations  and  warranties  of Trenwick
contained in this Agreement that are not so qualified  shall be true and correct
in all  material  respects,  in each case as of the date of this  Agreement  and
(except to the extent such representations and warranties speak as of an earlier
date) as of the  Closing  Date as  though  made as of and on the  Closing  Date,
except for such  failure or failures to be true and correct (or true and correct
in all material respects) as would not have or be




                                       72
<PAGE>



reasonably expected to have, individually or in the aggregate, a Material
Adverse Effect on Trenwick.

         (c)  Compliance  with  Conditions.   LaSalle  Holdings  shall  receive
customary closing documents in form and substance reasonably satisfactory to it,
including  a  certificate  of  an  executive  officer  of  Trenwick   certifying
compliance with the conditions set forth in Sections 6.3(a) and (b).

         (d)  Comfort  Letters.   LaSalle  Holdings  shall  have  received  from
PricewaterhouseCoopers LLP the letters described in Section 5.17(b).

         (e) Consents  and  Approvals.  LaSalle  Holdings  shall  have  received
evidence, in form and substance reasonably satisfactory to it, that all consents
and  approvals set forth in Section 3.8 of the Trenwick  Disclosure  Letter have
been obtained.

         (f) Rights  Agreement.  Trenwick shall have taken all necessary  action
pursuant to Section 3.20 so that, as of immediately prior to the Effective Time,
(i)  none  of  Trenwick,  New  Holdings  and  LaSalle  Holdings  will  have  any
obligations under the Rights or the Rights Agreement and (ii) the holders of the
Rights will have no rights under the Rights or the Rights Agreement.

         (g)  Fiduciary  Duties.  The Board of Directors of Trenwick  shall not
have (A)  withdrawn  or  modified  or  changed  in a manner  adverse  to LaSalle
Holdings its approval or  recommendation  of this  Agreement in order to approve
and permit  Trenwick to execute a  definitive  agreement  relating to a Trenwick
Superior Proposal (as defined in Section 5.3(a)(ii)), and (B) determined in good
faith,  after  consultation  with  outside  legal  counsel to Trenwick  that the
failure  to take  such  action  as set  forth  in the  preceding  clause  (A) is
reasonably  likely to result in the breach of the respective Board of Directors'
fiduciary duties under applicable law.

         (h) Baker & McKenzie Opinion.  In addition to those matters set forth
in Section 6.3(h) of the Trenwick  Disclosure  Letter, New Holdings and Trenwick
shall have received an opinion of Baker & McKenzie, dated the Effective Date, on
the basis of facts,  representations  and  assumptions set forth in such opinion
that are consistent with the facts existing on the Effective Date  substantially
to the effect that Trenwick shall treat the Plan of  Reorganization as a taxable
disposition of assets directly held by Trenwick,  but that Trenwick shall not be
subject to U.S.  federal  income tax in excess of $40.0  million with respect to
such  gain.  In  rendering  such  opinion,  counsel  may  require  and rely upon
representations  contained  in  certificates  of officers  of LaSalle  Holdings,
LaSalle Re, Trenwick and New Holdings,  including  representations regarding the
adjusted tax basis of the assets of Trenwick.  In  addition,  in rendering  such
opinion,  counsel  may  require and rely upon  opinions  prepared  by  valuation
experts,  including  opinions  regarding  the fair market value of the assets of
Trenwick, foreign counsel and others.




                                       73
<PAGE>

         (i) No  Material  Adverse  Change.  At any time  after the date of this
Agreement, there shall not have occurred any Material Adverse Change relating to
Trenwick;  provided, that this condition shall no longer be applicable following
the approval of the Trenwick stockholders.


                                    ARTICLE 7

                           TERMINATION AND ABANDONMENT

         Section 7.1  Termination  by  Trenwick  or  LaSalle  Holdings.
Anything herein contained to the contrary notwithstanding, this Agreement may be
terminated and the Plans contemplated  hereby may be abandoned at any time prior
to the earlier of the Scheme  Effective Time or Merger  Effective Time,  whether
before or after approval of the Plans by the  shareholders  of LaSalle  Holdings
and LaSalle Re or the stockholders of Trenwick, respectively:

         (a)     by the mutual written consent of LaSalle Holdings and Trenwick;

         (b)     by either  LaSalle  Holdings or  Trenwick by written notice to
the other:

                  (i) if the Effective Time shall not have occurred on or before
                  June 30, 2000; provided,  however, that the right to terminate
                  this  Agreement  under  this  Section  7.1(b)(i)  shall not be
                  available to any party whose failure to fulfill any obligation
                  under this  Agreement  has been the cause of, or resulted  in,
                  the failure of the  Effective  Time to occur on or before such
                  date;

                  (ii) if a Governmental Authority shall have issued a final and
                  nonappealable  order,  decree  or  ruling  or taken  any other
                  action  (which  order,  decree,  ruling  or other  action  the
                  parties hereto shall use their commercially reasonable efforts
                  to lift), in each case, permanently restraining,  enjoining or
                  otherwise  prohibiting the  transactions  contemplated by this
                  Agreement and such order, decree, ruling or other action shall
                  have become final and nonappealable;

                  (iii) if the required approval of the classes of stockholders
                  of Trenwick shall not have been obtained by reason of the
                  failure to obtain  the  required  vote at a duly held meeting
                  of such stockholders or at any  adjournment or  postponement
                  thereof; provided, that, if the terminating party is Trenwick,
                  Trenwick shall  not be in material breach  of its obligations
                  under Section 5.8;

                  (iv) if the required approval of the shareholders  of LaSalle
                  Holdings and LaSalle Re shall not have been obtained by reason
                  of the  failure  to obtain  the  required  vote at a duly held
                  meeting  of  such   shareholders  or  at  any  adjournment  or
                  postponement thereof; provided, that, if the terminating party
                  is LaSalle Holdings, LaSalle Holdings shall not be in material
                  breach of its obligations under Section 5.8; or



                                       74
<PAGE>


                  (v) if any single  natural  catastrophe  shall  have  occurred
                  which would  result in Net Losses to LaSalle  Holdings and its
                  Subsidiaries   or  to  Trenwick   and  its   Subsidiaries   of
                  $100,000,000 or more.

         Section 7.2      Termination by Trenwick.

         (a) Trenwick may terminate this  Agreement  prior to the Effective Time
if LaSalle  Holdings (x) breaches or fails in any material respect to perform or
comply with any of its covenants and agreements contained herein or (y) breaches
its  representations  or  warranties  and  such  breach  would  have or would be
reasonably  likely to have a Material Adverse Effect on LaSalle Holdings and its
Subsidiaries,  in each case such that the conditions set forth in Section 6.2(a)
or 6.2(b)  would not be  satisfied;  provided,  however,  that if such breach is
cured by the  breaching  party within ten (10) days  following  the discovery of
such breach,  Trenwick may not terminate this Agreement pursuant to this Section
7.2.

         (b) Trenwick may terminate this  Agreement  prior to the Effective Time
if LaSalle Holdings has (A) withdrawn or modified or changed in a manner adverse
to Trenwick its approval or recommendation of this Agreement,  or (B) determined
in good faith, after consultation with outside legal counsel to LaSalle Holdings
that the failure to take such action as set forth in the preceding clause (A) is
reasonably  likely to result in the breach of the respective Board of Directors'
fiduciary duties under applicable law.

         (c) Prior to the Effective Time,  Trenwick may terminate this Agreement
as provided in Section  5.3(a)(ii);  provided,  that  Trenwick  shall have given
LaSalle  Holdings  forty-eight  (48)  hours  advance  notice of any  termination
pursuant  to this  Section  7.2(b) and that  Trenwick  shall  have paid  LaSalle
Holdings the Trenwick  Termination Fee required to be paid by Trenwick  pursuant
to Section 7.4(b) hereof. Trenwick agrees to notify LaSalle Holdings promptly if
it is no longer prepared to accept the Trenwick Superior Proposal.

         Section 7.3 Termination by LaSalle Holdings.

         (a)  LaSalle  Holdings  may  terminate  this  Agreement  prior  to  the
Effective  Time if Trenwick  (x)  breaches or fails in any  material  respect to
perform or comply with any of its covenants and agreements  contained  herein or
(y) breaches its  representations  or  warranties  and such breach would have or
would be reasonably likely to have a Material Adverse Effect on Trenwick and its
Subsidiaries,  in each case such that the conditions set forth in Section 6.3(a)
or 6.3(b)  would not be  satisfied;  provided,  however,  that if such breach is
cured by the  breaching  party within ten (10) days  following  the discovery of
such breach,  LaSalle Holdings may not terminate this Agreement pursuant to this
Section 7.3(a).



                                       75
<PAGE>


         (b)  LaSalle  Holdings  may  terminate  this  Agreement  prior  to  the
Effective  Time if Trenwick has (A) withdrawn or modified or changed in a manner
adverse to LaSalle Holdings its approval or recommendation of this Agreement, or
(B) determined in good faith,  after  consultation with outside legal counsel to
Trenwick  that the  failure to take such  actions as set forth in the  preceding
clause (A) is reasonably  likely to result in the breach of the respective Board
of Directors' fiduciary duties under applicable law.

         (c) Prior to the Effective  Time,  LaSalle  Holdings may terminate this
Agreement  as  provided  in  Section  5.3(b)(ii);  provided,  that  LaSalle
Holdings shall have given Trenwick  forty-eight (48) hours advance notice of any
termination pursuant to this Section 7.3(b) and that LaSalle Holdings shall have
paid  Trenwick  the  LaSalle  Termination  Fee  required  to be paid by  LaSalle
Holdings  pursuant to Section 7.4(c) hereof.  LaSalle  Holdings agrees to notify
Trenwick  promptly if it is no longer  prepared  to accept the LaSalle  Holdings
Superior Proposal.

         Section 7.4  Procedure and Effect of Termination.

         (a) In the event of the  termination of this  Agreement,  except as set
forth in Section  7.4(b) and Section  7.4(c),  none of the parties  hereto shall
have  any  obligation  to  perform  hereunder  from and  after  the date of such
termination,    except   that   Sections   5.4   (the   last   sentence    only)
(Confidentiality),  5.6 (Public Announcements),  8.5 (Expenses and Obligations),
8.7 (Notices) and 8.8 (Governing Law) shall survive such  termination and remain
in full force and effect notwithstanding such termination. No termination hereof
shall relieve any party from any liability  resulting  from any breach of any of
its  representations,  warranties,  covenants  or  agreements  set forth in this
Agreement.

         (b) If this  Agreement  is  terminated  by (i) any  party  pursuant  to
Section 7.1(b)(i) or 7.1(b)(iii),  and in either case there shall have been made
or commenced a Trenwick  Takeover  Proposal,  which Trenwick  Takeover  Proposal
shall not have been absolutely and unconditionally withdrawn and abandoned as of
the date of such termination,  (ii) Trenwick pursuant to Section 7.2(c) or (iii)
LaSalle  Holdings  pursuant  to Section  7.3(a) if there is a Trenwick  Takeover
Proposal  outstanding  at the time of the breach or 7.3(b),  then Trenwick shall
pay LaSalle  Holdings a  non-refundable  termination  fee of  $12,000,000,  plus
expenses not to exceed $2,000,000 (the "Trenwick Termination Fee"), which amount
shall be payable by wire transfer of same-day funds prior to, and as a condition
of, the effectiveness of such termination.

         (c) If this  Agreement  is  terminated  by (i) any  party  pursuant  to
Section 7.1(b)(i) or 7.1(b)(iii),  and in either case there shall have been made
or  commenced a LaSalle  Holdings  Takeover  Proposal,  which  LaSalle  Holdings
Takeover Proposal shall not have been absolutely and  unconditionally  withdrawn
and abandoned as of the date of such termination, (ii) LaSalle Holdings pursuant
to Section  7.3(c) or (iii)  Trenwick  pursuant to Section  7.2(a) if there is a
LaSalle  Holdings  Takeover  Proposal  outstanding  at the time of the breach or
7.2(b),  then LaSalle Holdings shall pay Trenwick a  non-refundable  termination
fee of  $12,000,000,  plus  expenses  not to  exceed  $2,000,000  (the  "LaSalle
Termination  Fee"),  which amount shall be payable by wire  transfer of same-day
funds prior to, and as a condition of, the effectiveness of such termination.




                                       76


<PAGE>
                                    ARTICLE 8

                            MISCELLANEOUS PROVISIONS

        Section 8.1   Non-Survival of Representations, Warranties, Covenants and
Agreements.  None of the  representations,  warranties,  covenants or agreements
contained in this Agreement or in any Disclosure Letter, Exhibit or any document
delivered pursuant to this Agreement shall survive the Closing, except for those
covenants and  agreements  contained in this Agreement that by their terms apply
or are to be performed in whole or in part after the Closing.

          Section 8.2 Amendment  and  Modification.  Subject to applicable law,
this  Agreement may be amended,  modified or  supplemented  only by written
agreement signed on behalf of each party hereto at any time prior to the earlier
of the Merger Effective Time or the Scheme Effective Time with respect to any of
the  terms  contained   herein  except  that  (i)  after  the  meetings  of  the
stockholders of Trenwick as contemplated by Section 5.8, Trenwick  Consideration
to be paid pursuant to this Agreement to the holders of Trenwick Shares shall in
no event  be  decreased  and the form of  consideration  to be  received  by the
holders  of such  Trenwick  Shares  in the Plan of  Merger  shall in no event be
altered  without the  approval of such  holders,  (ii) after the meetings of the
shareholders  of  LaSalle  Holdings  as  contemplated  by Section  5.8,  LaSalle
Consideration  to be paid  pursuant to this  Agreement to the holders of LaSalle
Holdings Shares shall in no event be decreased and the form of  consideration to
be  received  by the holders of such  LaSalle  Holdings  Shares in the Scheme of
Arrangement  shall in no event be altered  without the approval of such holders,
and (iii) after the meetings of the  stockholders of Trenwick,  LaSalle Holdings
or LaSalle Re as  contemplated  by Section 5.8, there shall be made no amendment
that by law requires further approval by such  stockholders  without the further
approval of such stockholders.

         Section 8.3     Waiver of Compliance; Consents.

         (a) Any  failure  of any party to this  Agreement  to  comply  with any
obligation,  covenant,  agreement or  condition  herein may be waived by written
instrument  executed by each other party to this  Agreement,  but such waiver or
failure  to  insist  upon  strict  compliance  with such  obligation,  covenant,
agreement  or  condition  shall not  operate  as a waiver of, or  estoppel  with
respect to, any subsequent or other failure.

         (b) Whenever this Agreement requires or permits consent by or on behalf
of any  party  hereto,  such  consent  shall  be given  in  writing  in a manner
consistent with the requirements for a waiver of compliance as set forth in this
Section 8.3.

         Section 8.4  Severability  and  Validity.  The  provisions  set  forth
in this  Agreement  are  severable.  If any term,  provision,  covenant  or
restriction  of this  Agreement is held by record of competent  jurisdiction  or
other  authority to be invalid,  void or  unenforceable  in any  jurisdiction or
against its regulatory or public policy,  the remainder of this  Agreement,  and
the application of such provision to other Persons or  circumstances,  shall not
be affected thereby and shall remain valid and enforceable in such jurisdiction,
and any such  invalidity  or  unenforceability  in any  jurisdiction  shall  not
invalidate or render  unenforceable  such  provision in any other  jurisdiction.
Upon a  determination  that any term,  provision,  covenant  or  restriction  is
invalid, void or unenforceable or against the regulatory or public policy of the
governing  jurisdiction,  the parties  hereto  shall  negotiate in good faith to
modify  this  Agreement  so as to effect the  original  intent of the parties as
closely as possible to the fullest  extent  permitted  by  applicable  law in an
acceptable  manner  to the  end  that  the  transactions  contemplated  by  this
Agreement are fulfilled to the extent possible.



                                       77

<PAGE>

     Section 8.5   Expenses and Obligations. Each of the parties shall pay its
own expenses incurred in connection with the negotiation and preparation of
this Agreement,  the performance of its covenants herein and the effectuation of
the transactions  contemplated hereby, including,  without limitation,  all fees
and  disbursements  of its respective  legal counsel,  advisors and accountants;
provided,  however, that nothing in this Section 8.5 shall negate any obligation
of either LaSalle  Holdings or Trenwick to pay the  termination fee specified in
Sections  7.4(b) and (c). Each of the LaSalle  Holdings and Trenwick  shall bear
and pay  one-half  of the filing  fees,  printing  expenses  and  mailing  costs
incurred in connection with (1) the filing, printing and mailing of the Form S-4
and the Joint Proxy Statement (including SEC filing fees) and (2) the filings of
any  required  premerger  notification  and  report  forms  under  the  HSR  Act
(including filing fees) and one-half of the fees of the Settlement  Auditor.  In
the  event  that  the  transactions  contemplated  by  this  Agreement  are  not
consummated,  each of the parties  shall  indemnify  and hold harmless the other
parties against any claim for fees or commissions of brokers, finders, agents or
bankers  retained or purportedly  retained by the indemnitor party in connection
with the transactions contemplated by this Agreement.

        Section 8.6   Parties in Interest. This Agreement shall be binding upon
and inure  solely to the  benefit of each party  hereto and nothing in this
Agreement,  express or implied,  is intended to confer upon any other Person any
rights  or  remedies  of any  nature  whatsoever  under  or by  reason  of  this
Agreement,  except for Section  5.13 (which is intended to be for the benefit of
the Persons referred to therein and may be enforced by such Persons).

         Section 8.7  Notices.  All  notices,   requests,   claims,   demands
and other  communications  hereunder shall be in writing and shall be given
(and  shall be deemed to have been duly  given  upon  receipt)  by  delivery  in
person,  by  facsimile  (which  is  confirmed)  or  sent  by  overnight  courier
(providing  proof of  delivery) or by  registered  or  certified  mail  (postage
prepaid, return receipt requested),  to the other party at the following address
(or at such other address for a party as shall be specified by like notice):

         if to LaSalle Holdings before the Effective Date, to:

                  LaSalle Re Holdings Limited
                  25 Church Street
                  P.O. Box HM 1502
                  Hamilton HM FX, Bermuda
                  Fax: (441) 292-2656
                  Attention: Guy D. Hengesbaugh
         with a copy to:

                  Mayer, Brown & Platt
                  190 South LaSalle Street
                  Chicago, Illinois 60603
                  Fax: (312) 701-7711
                  Attention: Richard W. Shepro, Esq.




                                       78
<PAGE>



         if to Trenwick before the Effective Date, to:

                  Trenwick Group Inc.
                  One Canterbury Green
                  Stamford, Connecticut 06901
                  Fax: (203) 353-5550
                  Attention: John V. Del Col, Esq.

         with a copy to:

                  Baker & McKenzie
                  805 Third Avenue
                  New York, New York 10022
                  Fax: (212) 891-3835
                  Attention: James R. Cameron, Esq.

         if to LaSalle Holdings, Trenwick or New Holdings after the Effective
 Date:

                  Gowin Holdings International Limited
                  c/o Appleby Spurling & Kempe
                  Cedar House
                  41 Cedar Avenue
                  P.O. Box HM 1178
                  Hamilton HM EX, Bermuda
                  Fax: (441) 292-8666
                  Attention: Warren Cabral, Esq.

         with a copy to:

                  Baker & McKenzie
                  805 Third Avenue
                  New York, New York 10022
                  Fax: (212) 891-3835
                  Attention: James R. Cameron, Esq.

or to such  other  address  as the  person  to whom  notice  is  given  may have
previously furnished to the other in writing in the manner set forth above.



                                       79
<PAGE>

     Section 8.8 Governing Law. Except for Article 2, which shall be governed by
and construed in accordance with the laws of Bermuda and Delaware, as applicable
according to the context thereof (i.e.,  with matters  relating to the Scheme of
Arrangement  being  governed by Bermuda law and matters  relating to the Plan of
Merger being governed by Delaware law),  this Agreement shall be governed by and
construed in accordance  with the laws of the State of Delaware,  without regard
to the conflicts of laws rules thereof. In addition,  each of the parties hereto
(a) consents to submit itself to the personal jurisdiction of any Delaware Court
in the event any dispute arises out of this Agreement or any of the transactions
contemplated  by this  Agreement and (b) agrees that it will not attempt to deny
or defeat such  personal  jurisdiction  or venue by motion or other  request for
leave from any such  Delaware  Court,  and (c) agrees that it will not bring any
action  relating to this Agreement or any of the  transactions  contemplated  by
this Agreement in any court other than any Delaware Court.

         Section 8.9 Counterparts.  This  Agreement  may be  executed  in  two
or more counterparts,  each of which shall be an original, and all of which
shall be considered one and the same  agreement and shall become  effective when
one or more  counterparts  have been signed by each of the parties and delivered
to the other party.

         Section 8.10 Headings.  The  Article  and  Section  headings contained
in this Agreement are solely for the purpose of reference,  are not part of
the  agreement  of the  parties  and shall not affect in any way the  meaning or
interpretation  of this  Agreement.  References to Articles or Sections,  unless
otherwise specified, are to Articles and Sections of this Agreement.

         Section 8.11  Entire  Agreement:    Assignment.  This  Agreement,
including the documents and instruments referred to herein and therein, and
the  Confidentiality  Letters embodies the entire agreement and understanding of
the  parties  hereto in  respect  of the  subject  matter  contained  herein and
therein.  There  are no  agreements,  restrictions,  promises,  representations,
warranties,  covenants or undertakings,  other than those expressly set forth or
referred  to  herein.  This  Agreement   supersedes  all  prior  agreements  and
understandings  between the parties with respect to such subject  matters.  This
Agreement  shall not be assigned by operation of law or  otherwise,  except with
the prior  written  consent  of each  other  party  hereto;  provided,  that all
transactions  contemplated  by Section 2.1(b) and (c) shall not be considered an
assignment  by operation of law or otherwise  for purposes of this Section 8.11.
Any assignment in violation of the preceding  sentence shall be void. Subject to
the preceding two sentences,  this Agreement will be binding upon,  inure to the
benefit of, and be enforceable by, the parties and their  respective  successors
and assigns.

         Section 8.12  Interpretation.  When a reference  is made in this
Agreement  to an  Article,  Section,  Exhibit,  Letter  or  Schedule,  such
reference  shall be to an  Article  or  Section  of,  or an  Exhibit,  Letter or
Schedule to, this Agreement  unless otherwise  indicated.  The table of contents
and headings  contained in this  Agreement are for  reference  purposes only and
shall not affect in any way the  meaning or  interpretation  of this  Agreement.
Whenever  the  words  "include,"  "includes"  or  "including"  are  used in this
Agreement,   they  shall  be  deemed  to  be  followed  by  the  words  "without
limitation." The phrase "made available" in this



                                       80
<PAGE>


Agreement shall mean that the information referred to has been made available if
requested by the party to whom such  information  is to be made  available.  The
words  "hereof",  "herein" and  "hereunder" and the words or similar import when
used in this  Agreement  shall refer to this Agreement as a whole and not to any
particular  provision of this  Agreement.  All terms  defined in this  Agreement
shall have the defined  meanings when used in any  certificate or other document
made  or  delivered  pursuant  hereto  unless  otherwise  defined  therein.  The
definitions  contained in this  Agreement are applicable to the singular as well
as the  plural  forms  of  such  terms  and to the  masculine  as well as to the
feminine and neuter genders of such term.  Any agreement,  instrument or statute
defined or referred to herein or in any agreement or instrument that is referred
to herein  means  such  agreement,  instrument  or  statute as from time to time
amended,  modified or  supplemented,  including  (in the case of  agreements  or
instruments) by waiver or consent and (in the case of statutes) by succession of
comparable successor statutes. References to a person are also to its permitted
successors and assigns.





                                      81

<PAGE>


         IN  WITNESS  WHEREOF,  each  of the  parties  hereto  has  caused  this
Agreement to be signed and sealed on its behalf by its duly authorized officers,
all as of the day and year first above written.

                                       LASALLE RE HOLDINGS LIMITED


                                       By: /s/ Guy D. Hengesbaugh
                                           -------------------------------------
                                       Name:  Guy D. Hengesbaugh
                                       Title: President and Chief Executive
                                              Officer


                                       LASALLE RE LIMITED

                                       By: /s/ Guy D. Hengesbaugh
                                           -------------------------------------
                                       Name:  Guy D. Hengesbaugh
                                       Title: President and Chief Executive
                                              Officer


                                       GOWIN HOLDINGS INTERNATIONAL LIMITED

                                       By: /s/ John V. Del Col
                                           -------------------------------------
                                       Name:  John V. Del Col
                                       Title: Director


                                       TRENWICK GROUP INC.

                                       By: /s/ James F. Billett, Jr.
                                           -------------------------------------
                                       Name:  James F. Billett, Jr.
                                       Title: Chairman, President and Chief
                                              Executive Officer


                                       TRENWICK GROUP (DELAWARE) INC.

                                       By:  /s/ James F. Billett, Jr.
                                            ------------------------------------
                                       Name:  James F. Billett, Jr.
                                       Title: Chairman, President and Chief
                                              Executive Officer




                         LASALLE STOCK OPTION AGREEMENT

                  STOCK  OPTION  AGREEMENT,  dated as of December  19, 1999 (the
"Agreement")  by  and  between  Trenwick  Group  Inc.,  a  Delaware  corporation
("Trenwick"  or the  "Issuer"),  and  LaSalle  Re  Holdings  Limited,  a company
organized under the laws of Bermuda ("LaSalle").

                  WHEREAS,  concurrently with the execution and delivery of this
Agreement,  LaSalle,  LaSalle Re Limited,  a company organized under the laws of
Bermuda,  Trenwick,  Trenwick Group (Delaware) Inc., a Delaware  corporation and
Gowin Holdings  International  Limited,  a company  organized  under the laws of
Bermuda ("New Holdings"), are entering into an Agreement, Scheme of Arrangement,
Plan of  Merger  and Plan of  Reorganization  dated as of the date  hereof  (the
"Business Combination Agreement"); and

                  WHEREAS, as a condition to LaSalle's willingness to enter into
the Business Combination  Agreement,  LaSalle has requested that Trenwick agree,
and  Trenwick  has so agreed,  to grant to LaSalle an option to  purchase  up to
3,462,164 shares of   common  stock,  par value  $0.10 per  share,  of  Trenwick
("Trenwick Common Stock"),  together with any associated rights under the Rights
Agreement  dated as of  September  24, 1997 between  Trenwick and First  Chicago
Trust Company of New York  ("Trenwick  Common  Stock"),  in accordance  with the
terms and subject to the conditions set forth herein.

                  NOW,  THEREFORE,  to induce LaSalle to enter into the Business
Combination  Agreement,  and in  consideration  of the  foregoing and the mutual
representations,  warranties,  covenants and  agreements set forth herein and in
the  Business  Combination  Agreement,  the  parties  hereto  agree as  follows.
Capitalized  terms used herein but not defined  herein  shall have the  meanings
ascribed to them in the Business Combination Agreement.

                  1. Grant of Option.  Subject to the terms and  conditions  set
forth  herein,  Trenwick  hereby  grants to LaSalle an  irrevocable  option (the
"Trenwick Option") to purchase up to 3,462,164 (as adjusted as set forth herein)
shares (the  "Option  Shares") of Trenwick  Common  Stock (such number of Option
Shares representing 19.9% of the Trenwick Common Stock issued and outstanding on
the date hereof) in the manner set forth below at a price (the "Exercise Price")
of $18.04 per Option Share (which price per share is equal to the average of the
last  sale  prices  of  Trenwick  Common  Stock  on the ten  (10)  trading  days
immediately prior to the date of public announcement of the Business Combination
Agreement  payable in cash or by cashless  exercise in accordance with Section 4
hereof.  Notwithstanding  the foregoing,  in no event shall the number of Option
Shares for which the Trenwick  Option is exercisable  exceed 19.9% of the number
of issued and outstanding shares of Trenwick Common Stock.


<PAGE>

                  2. Exercise of Option. The Trenwick Option may be exercised by
LaSalle,  in whole  or in  part,  at any  time or from  time to time  after  the
Business Combination Agreement becomes terminable by LaSalle under circumstances
which would or could  entitle  LaSalle to receive the Trenwick  Termination  Fee
pursuant to Section  7.4(b) of the  Business  Combination  Agreement (a "Trigger
Event")  (regardless of whether the Business  Combination  Agreement is actually
terminated or whether there occurs a closing  involving  LaSalle).  In the event
LaSalle  wishes to  exercise  the  Trenwick  Option,  LaSalle  shall  deliver to
Trenwick a written notice (an "Exercise Notice")  specifying the total number of
Option  Shares it wishes to purchase,  and specify  whether such  exercise is in
cash or by cashless  exercise in accordance with Section 4 hereof.  Each closing
of a purchase of Option Shares (an "Option Closing") shall occur, but subject to
the satisfaction or waiver of the conditions set forth in Section 3 hereof, at a
place,  on a date and at a time  designated  by  LaSalle in an  Exercise  Notice
delivered  at least  two (2)  business  days  prior  to the  date of the  Option
Closing.  The  Trenwick  Option  shall  terminate  upon the  earlier of: (i) the
Effective Time; (ii) the termination of the Business Combination Agreement other
than under  circumstances  which also  constitute a Trigger Event;  or (iii) the
180th day  following a Trigger  Event (or if, at the  expiration of such 180 day
period the  Trenwick  Option  cannot be  exercised  by reason of any  applicable
judgment,  decree,  order, law or regulation,  ten (10) business days after such
impediment  to exercise  shall have been  removed or shall have become final and
not subject to appeal,  but in no event  under this clause  (iii) later than the
365th day following such Trigger  Event).  Notwithstanding  the  foregoing,  the
Trenwick  Option may not be exercised if LaSalle is in material breach of any of
its representations or warranties, or in material breach of any of its covenants
or  agreements,  contained  in this  Agreement  or in the  Business  Combination
Agreement. Upon the giving by LaSalle to Trenwick of the Exercise Notice and the
tender  of  the  applicable   aggregate  Exercise  Price,  but  subject  to  the
satisfaction or waiver of the conditions set forth in Section 3 hereof,  LaSalle
shall be deemed to be the holder of record of the Option  Shares  issuable  upon
such exercise,  notwithstanding  that the stock transfer books of Trenwick shall
then be closed or that  certificates  representing  such Option Shares shall not
then be actually delivered to LaSalle.

                  3. Conditions to Closing.  The obligation of Trenwick to issue
the Option  Shares to LaSalle  hereunder  is  subject to the  conditions,  which
(other than the  conditions  described in clauses (i), (iii) and (iv) below) may
be waived by Trenwick in its sole discretion,  that (i) all waiting periods,  if
any,  under  the HSR  Act,  applicable  to the  issuance  of the  Option  Shares
hereunder  shall have expired or have been  terminated;  (ii) the Option  Shares
shall  have  been  approved  for  listing  on the NYSE upon  official  notice of
issuance;  (iii)  all  consents,  approvals,  orders  or  authorizations  of, or
registrations,  declarations  or  filings  with,  any  federal,  state  or local
administrative   agency  or  commission  or  other   federal,   state  or  local
Governmental  Authority,  including  without  limitation,  the Bermuda  Monetary
Authority, if any, required in connection with the issuance of the Option Shares
hereunder  shall  have  been  obtained  or made,  as the case may be  including,
without limitation,  by LaSalle; and (iv) no preliminary or permanent injunction
or  other  order  or  decree  by any  court of  competent  jurisdiction,  law or
regulation  prohibiting  or  otherwise  restraining  such  issuance  shall be in
effect.


                                       2
<PAGE>


                  4. Payment and Delivery of Certificates.

                  (a) At any Option Closing,  LaSalle  shall pay to Trenwick the
aggregate  purchase price (equal to the Exercise Price  multiplied by the number
of Option  Shares to be  purchased  at such  Option  Closing)  for the shares of
Trenwick Common Stock purchased  pursuant to the exercise of the Trenwick Option
in immediately  available funds by wire transfer to a bank account designated in
writing by Trenwick;  provided,  however, that failure or refusal of Trenwick to
designate such account shall not preclude  LaSalle from  exercising the Trenwick
Option.  At LaSalle's  option,  in lieu of delivering  the cash Exercise  Price,
LaSalle may instruct  Trenwick in writing to deduct from the number of shares of
Trenwick  Common  Stock that would  otherwise  be issued upon such  exercise,  a
number of shares of Trenwick  Common Stock equal to the quotient  obtained  from
dividing:

                  (x) the  product  obtained  by  multiplying  (1) the number of
         shares of Trenwick  Common Stock for which the Trenwick Option is being
         exercised and (2) the Exercise Price then in effect, by

                  (y) the Fair Market Value of a share of Trenwick Common Stock.

"Fair Market Value" shall have the meaning specified in Section 12(b)(v).

                  (b) At any Option Closing, simultaneously with the delivery of
immediately  available funds as provided in Section 4(a),  Trenwick will deliver
to  LaSalle a  certificate  or  certificates  representing  the number of Option
Shares to be purchased by LaSalle at such Option  Closing,  which Option  Shares
will be free and clear of all liens,  claims,  charges and  encumbrances  of any
kind  whatsoever  and if the option is  exercised in part only,  Trenwick  shall
deliver a new option  evidencing  the rights of LaSalle  thereof to purchase the
balance of the shares  purchasable  hereunder  and (ii)  LaSalle will deliver to
Trenwick a copy of this  Agreement  and a letter  agreeing that LaSalle will not
offer to sell or otherwise dispose of such shares in violation of applicable law
or the provisions of this Agreement. If at the time of issuance of Option Shares
pursuant  to an  exercise  of the  option  hereunder,  Trenwick  shall  not have
redeemed the Trenwick Rights, or shall have issued any similar securities,  then
each Option Share issued  pursuant to such exercise will also  represent  such a
corresponding  Trenwick Right or new rights with terms substantially the same as
and at least as  favorable  to LaSalle as are  provided in the  Trenwick  Rights
Agreement or similar agreement then in effect.  Trenwick shall pay all expenses,
and any and all United States  federal,  state and local taxes and other charges
that may be payable in connection  with the  preparation,  issue and delivery of
stock  certificates under this Section 4 in the name of LaSalle or its designee.
Trenwick  shall use its  reasonable  best efforts to cause the  Trenwick  Common
Stock being  delivered  at the Option  Closing to be approved for listing on the
NYSE and shall pay all expenses in connection  with the application for approval
and the listing of such shares.



                                       3

<PAGE>

                  5. Representations and Warranties of Trenwick. Trenwick hereby
represents  and  warrants to LaSalle  that (a)  Trenwick is a  corporation  duly
organized,  validly existing and in good standing under the laws of the State of
Delaware and has the corporate power and authority to enter into this Agreement,
(b)  the  execution  and  delivery  of  this   Agreement  by  Trenwick  and  the
consummation by Trenwick of the transactions  contemplated hereby have been duly
authorized  by all  necessary  corporate  action on the part of Trenwick  and no
other  corporate  proceedings on the part of Trenwick are necessary to authorize
this  Agreement  or  any of  the  transactions  contemplated  hereby,  (c)  this
Agreement has been duly executed and delivered by Trenwick,  constitutes a valid
and binding  obligation of Trenwick and,  assuming this Agreement  constitutes a
valid and binding  obligation of LaSalle,  is  enforceable  against  Trenwick in
accordance with its terms, (d) Trenwick has taken all necessary corporate action
to authorize  and reserve for issuance and to permit it to issue,  upon exercise
of the  Trenwick  Option,  and at all times  from the date  hereof  through  the
expiration of the Trenwick Option will have reserved,  3,462,164  authorized and
unissued  Option Shares,  such amount being subject to adjustment as provided in
Section 9, all of which, upon their issuance and delivery in accordance with the
terms of this Agreement,  will be validly issued,  fully paid and nonassessable,
(e) upon  delivery  of the Option  Shares to LaSalle  upon the  exercise  of the
Trenwick  Option,  LaSalle will acquire the Option  Shares free and clear of all
claims,  liens,  charges,  encumbrances  and  security  interests  of any nature
whatsoever,  (f) none of Trenwick, any of its affiliates or anyone acting on its
or their  behalf has  issued,  sold or offered  any  security of Trenwick to any
person under  circumstances that would cause the issuance and sale of the Option
Shares,  as contemplated by this  Agreement,  to be subject to the  registration
requirements of the Securities Act as in effect on the date hereof and, assuming
the  representations  of LaSalle  contained in Section 6(d) are true and correct
and based on LaSalle's commitment in its letter referred to in Section 4 hereof,
the issuance,  sale and delivery of the Option Shares  hereunder would be exempt
from the  registration  and prospectus  delivery  requirements of the Securities
Act,  as in effect on the date hereof  (and  Trenwick  shall not take any action
which would cause the issuance, sale and delivery of the Option Shares hereunder
not to be exempt from such requirements),  and (g) the execution and delivery of
this Agreement by Trenwick does not, and,  subject to compliance with applicable
law, the consummation by Trenwick of the transactions  contemplated  hereby will
not,  violate,  conflict  with,  or result in a breach of any  provision  of, or
constitute a default (with or without notice or a lapse of time, or both) under,
or result in the termination  of, or accelerate the performance  required by, or
result  in  a  right  of  termination,  cancellation,  or  acceleration  of  any
obligation or the loss of a material  benefit under,  or the creation of a lien,
pledge,  security  interest or other  encumbrance on assets (any such violation,
conflict,  breach,  default,  termination,  acceleration,  right of termination,
cancellation or acceleration,  loss, or creation,  a "Violation") of Trenwick or
any of its subsidiaries,  pursuant to (i) any provision of the Trenwick By-Laws,
(ii) any provision of any material  loan or credit  agreement,  note,  mortgage,
indenture,  lease,  benefit  plan or other  agreement,  obligation,  instrument,
permit, concession,  franchise or license (a "Material Contract") of Trenwick or
any of its  subsidiaries  or to which  any of them is a party or by which any of
them or their  properties  or assets are bound,  or (iii) any  judgment,  order,
decree,  statute,  law, ordinance,  rule or regulation applicable to Trenwick or
any of its subsidiaries or any of their respective  properties or assets,  which
Violation,  in the case of each of clauses  (ii) or (iii),  would have  Material
Adverse Effect on Trenwick.

                                       4
<PAGE>


                  6.   Representations   and  Warranties  of  LaSalle.   LaSalle
represents  and  warrants  to  Trenwick  that  (a)  LaSalle  is a  company  duly
organized,  validly  existing and in good standing under the laws of Bermuda and
has the corporate  power and authority to enter into this Agreement and to carry
out its obligations hereunder,  (b) the execution and delivery of this Agreement
by LaSalle  and the  consummation  by LaSalle of the  transactions  contemplated
hereby have been duly authorized by all necessary  corporate  action on the part
of  LaSalle  and no  other  corporate  proceedings  on the part of  LaSalle  are
necessary to authorize  this Agreement or any of the  transactions  contemplated
hereby,  (c) this  Agreement has been duly executed and delivered by LaSalle and
constitutes  a valid and binding  obligation  of  LaSalle,  and,  assuming  this
Agreement constitutes a valid and binding obligation of Trenwick, is enforceable
against LaSalle in accordance with its terms, and (d) any Option Shares acquired
upon exercise of the Trenwick Option will be acquired for LaSalle's own account,
for  investment  purposes  only and will not be, and the Trenwick  Option is not
being,  acquired by LaSalle  with a view to the public  distribution  thereof in
violation  of any  applicable  provision  of the  Securities  Act,  and  (e) the
execution and delivery of this  Agreement by LaSalle does not,  and,  subject to
compliance with applicable law, the  consummation by LaSalle of the transactions
contemplated hereby will not, violate, conflict with, or result in the breach of
any provision of, or constitute a default (with or without  notice or a lapse of
time,  or both)  under,  or result in any  Violation  by  LaSalle  or any of its
subsidiaries,  pursuant to (i) any provision of the memorandum of association or
bye-laws  of  LaSalle,  (ii) any  Material  Contract  of  LaSalle  or any of its
subsidiaries  or to which  any of them is a party or by which any of them or any
of their properties or assets are bound, or (iii) any judgment,  order,  decree,
statute,  law, ordinance,  rule or regulation  applicable to LaSalle, any of its
subsidiaries or any of their respective  properties or assets,  which Violation,
in the case of each of clauses  (ii) or (iii),  would  have a  Material  Adverse
Effect on LaSalle.

                  7.   Restrictions on Transfer.

                  (a)  Restrictions on Transfer.  Prior to the first anniversary
of the  date on  which  LaSalle  purchases  any  Option  Shares  hereunder  (the
"Expiration Date"),  LaSalle shall not, directly or indirectly,  by operation of
law or otherwise,  sell, assign, pledge, or otherwise dispose of or transfer any
Option  Shares  acquired  by LaSalle  pursuant  to this  Agreement  ("Restricted
Shares")  beneficially  owned by it, other than in accordance with Section 7(b),
7(c) or  Section  8.  Subsequent  to the  Expiration  Date,  LaSalle  shall not,
directly or indirectly,  by operation of law or otherwise,  sell, assign, pledge
or otherwise dispose of or transfer any Restricted Shares  beneficially owned by
it  to  any  purchaser,   assignee,  pledgee  or  other  transferee  who  would,
immediately  after such  sale,  assignment,  pledge,  disposition  or  transfer,
beneficially  own more than  4.9% of the then  outstanding  voting  power of the
Issuer of the Restricted Shares, except in accordance with Section 7(b), 7(c) or
Section 8 and other than in market transactions at prevailing prices.

                                       5
<PAGE>


                  (b) Permitted Sales. Following the termination of the Business
Combination  Agreement,  LaSalle  shall be  permitted  to sell or  transfer  any
Restricted  Shares  beneficially  owned by it if such sale is made pursuant to a
tender or exchange  offer or merger that has been  approved or  recommended,  or
otherwise determined to be fair to and in the best interests of the shareholders
of Trenwick,  by a majority of the members of the Board of Directors of Trenwick
(which  majority shall include a majority of directors who were directors  prior
to the announcement of such tender or exchange offer or merger).

                  (c)  Trenwick's Right of First Refusal.  At any time after the
first  occurrence of a Trigger Event and prior to the  expiration of twenty-four
(24) months  immediately  following the first purchase of Trenwick  Common Stock
pursuant  to the  Trenwick  Option,  if LaSalle  shall  desire to sell,  assign,
transfer or  otherwise  dispose of any shares of Trenwick  Common Stock or other
securities  acquired by it pursuant to the Trenwick  Option,  LaSalle shall give
Trenwick written notice of the proposed  transaction (a "LaSalle Offer Notice"),
identifying the proposed transferee, accompanied by a copy of a binding offer to
purchase  such  Trenwick  Common  Stock  or  other  securities  signed  by  such
transferee  and setting forth the terms of the proposed  transaction.  A LaSalle
Offer  Notice  shall be deemed an offer by  LaSalle to  Trenwick,  which must be
accepted,  if at all,  within  five (5)  business  days of the  receipt  of such
LaSalle Offer Notice,  on the same terms and conditions and at the same price at
which  LaSalle is  proposing  to transfer  such  Trenwick  Common Stock or other
securities  to such  transferee.  The purchase of any  Trenwick  Common Stock or
other  securities by Trenwick  shall be settled within five (5) business days of
the date of the  acceptance of the offer and the purchase price shall be paid to
LaSalle in immediately  available  funds. In the event of the failure or refusal
of Trenwick to purchase  all of the Trenwick  Common  Stock or other  securities
covered by a LaSalle Offer Notice,  LaSalle may sell all, but not less than all,
of such Trenwick Common Stock or other securities to the proposed  transferee at
a price no less than the price  specified and on terms no more  favorable to the
transferee  than those set forth in the LaSalle Offer Notice;  provided that the
provisions  of this  sentence  shall not limit the rights  LaSalle may otherwise
have in the event Trenwick has accepted the offer contained in the LaSalle Offer
Notice and  wrongfully  refuses to purchase the  Trenwick  Common Stock or other
securities  subject  thereto.  The  requirements  of this Section 7(c) shall not
apply to (i) any disposition as a result of which the proposed  transferee would
not  beneficially  own more than three  percent (3%) of the  outstanding  voting
power of  Trenwick,  (ii) any  disposition  of  Trenwick  Common  Stock or other
securities  by a person  to whom  LaSalle  has  assigned  its  rights  under the
Trenwick  Option  with the  consent  of  Trenwick,  (iii) any sale by means of a
public offering  registered  under the Securities Act, or (iv) any transfer to a
wholly-owned  subsidiary  of LaSalle  which agrees in writing to be bound by the
terms hereof.

                                       6
<PAGE>


                  8.   Registration  Rights.  Following the  termination  of the
Business Combination Agreement, but not later than the second anniversary of the
last date that LaSalle acquired Option Shares under this Agreement,  LaSalle may
by written notice (the "Registration  Notice") to Trenwick  ("Trenwick") request
Trenwick to register  under the Securities Act all or any part of the Restricted
Shares beneficially owned by LaSalle (the "Registrable  Securities") pursuant to
a bona fide firm  commitment  underwritten  public offering in which LaSalle and
the  underwriters  shall  effect  as wide a  distribution  of  such  Registrable
Securities  as is  reasonably  practicable  and  shall  use  their  commercially
reasonable  efforts to prevent any person  (including any Group (as used in Rule
13d-5 under the Exchange Act)) and its affiliates from  purchasing  through such
offering  Restricted  Shares  representing  more  than one  percent  (1%) of the
outstanding  shares of common  stock of  Trenwick  on a fully  diluted  basis (a
"Permitted  Offering").  The  Registration  Notice shall  include a  certificate
executed by LaSalle and its proposed  managing  underwriter,  which  underwriter
shall be an  investment  banking firm of  nationally  recognized  standing  (the
"Manager"),  stating  that (i) they  have a good  faith  intention  to  commence
promptly a Permitted  Offering and (ii) the Manager in good faith believes that,
based  on the then  prevailing  market  conditions,  it will be able to sell the
Registrable  Securities  at a per share price equal to at least  eighty  percent
(80%) of the then Fair Market Value (as defined below) of such shares.  Trenwick
(and/or any person  designated  by  Trenwick)  shall  thereupon  have the option
exercisable by written notice delivered to LaSalle within five (5) business days
after the receipt of the Registration  Notice,  irrevocably to agree to purchase
all or any part of the Registrable Securities proposed to be so sold for cash at
a  price  (the  "Option  Price")  equal  to the  product  of (i) the  number  of
Registrable  Securities  to be so  purchased  by Trenwick and (ii) the then Fair
Market Value of such shares.  Any such  purchase of  Registrable  Securities  by
Trenwick (or its designee) hereunder shall take place at a closing to be held at
the principal  executive offices of Trenwick or at the offices of its counsel at
any reasonable date and time designated by Trenwick and/or such designee in such
notice  within  twenty (20)  business  days after  delivery of such notice.  Any
payment for the shares to be purchased  shall be made by delivery at the time of
such closing of the Option Price in immediately available funds. As used herein,
the "Fair Market  Value" of any share shall be the average of the daily  closing
sales  price for such share on the NYSE  during the ten (10) NYSE  trading  days
immediately preceding the date such Fair Market Value is to be determined.

                  If Trenwick does not elect to exercise its option  pursuant to
this  Section 8 with  respect to all  Registrable  Securities,  it shall use its
commercially  reasonable  efforts to effect,  as  promptly as  practicable,  the
registration under the Securities Act of the unpurchased  Registrable Securities
proposed  to be so sold;  provided,  however,  that  (i)  LaSalle  shall  not be
entitled to more than an  aggregate  of two  effective  registration  statements
hereunder and (ii)  Trenwick will not be required to file any such  registration
statement  during any period of time (not to exceed  ninety (90) days after such
request in the case of clauses  (A),  (B) or (C) below) when (A)  Trenwick is in
possession of material non-public information which it reasonably believes would
be  detrimental  to be  disclosed at such time and, in the opinion of counsel to
Trenwick,  such  information  would  have  to  be  disclosed  if a  registration
statement were filed at that time; (B) Trenwick is required under the Securities



                                       7

<PAGE>

Act to include audited financial  statements for any period in such registration
statement and such  financial  statements are not yet available for inclusion in
such  registration  statement;  or (C) Trenwick  determines,  in its  reasonable
judgment, that such registration would interfere with any financing, acquisition
or other  material  transaction  involving  Trenwick  or any of its  affiliates.
Trenwick  shall  use its  reasonable  best  efforts  to  cause  any  Registrable
Securities  registered pursuant to this Section 8 to be qualified for sale under
the securities or blue sky laws of such  jurisdictions as LaSalle may reasonably
request and shall continue such  registration or qualification in effect in such
jurisdiction;  provided, however, that Trenwick shall not be required to qualify
to do business in, or consent to general service of process in, any jurisdiction
by reason of this provision.

                  The  registration  rights  set  forth  in this  Section  8 are
subject  to  the  condition  that  LaSalle  shall  provide  Trenwick  with  such
information with respect to such holder's Registrable Securities,  the plans for
the distribution thereof, and such other information with respect to such holder
as, in the reasonable  judgment of counsel for Trenwick,  is necessary to enable
Trenwick to include in such  registration  statement all material facts required
to be disclosed with respect to a registration thereunder.

                  A registration effected under this Section 8 shall be effected
at Trenwick's expense, except for underwriting discounts and commissions and the
fees and the expenses of counsel to LaSalle,  and Trenwick  shall provide to the
underwriters such documentation (including certificates, opinions of counsel and
"comfort"   letters  from   auditors)  as  are  customary  in  connection   with
underwritten  public offerings as such underwriters may reasonably  require.  In
connection with any such  registration,  the parties agree (i) to indemnify each
other and the  underwriters in the customary manner (provided that LaSalle shall
only be required to indemnify other parties to such  underwriting  agreement for
information  relating to such LaSalle and  supplied by it for  inclusion in such
registration  statement),  (ii) to enter into an underwriting  agreement in form
and substance  customary for  transactions of such type with the Manager and the
other underwriters  participating in such offering and (iii) to take all further
actions which shall be reasonably necessary to effect such registration and sale
(including,  if the  Manager  deems it  necessary,  participating  in road  show
presentations).

                  Trenwick  shall  be  entitled  to  include  (at  its  expense)
additional  shares of its common stock in a  registration  effected  pursuant to
this  Section  8 only if and to the  extent  the  Manager  determines  that such
inclusion will not adversely affect the prospects for success of such offering.

                   9.  Adjustment  upon Changes in  Capitalization.  (a) Without
limitation to any restriction on Trenwick  contained in this Agreement or in the
Business  Combination  Agreement,  in the event of any change in Trenwick Common
Stock  by  reason  of  stock  dividends,   split-ups,  mergers,   amalgamations,
recapitalizations,  subdivisions,  conversions, combinations, exchange of shares
or the like, the type and number of shares or securities subject to the Trenwick
Option,  and the Exercise Price per Option Share provided in Section 1, shall be
adjusted appropriately to restore to LaSalle its rights hereunder, including the
right to  purchase  from the  Trenwick  (or its  successors)  shares of Trenwick
Common Stock representing 19.9% of the outstanding Trenwick Common Stock for the
aggregate Exercise Price calculated as of the date of this Agreement as provided
in Section 1.


                                       8
<PAGE>


                  (b) In the event that Trenwick  shall enter into an agreement:
(i) to consolidate with merge or amalgamate into any person,  other than LaSalle
or one of its  subsidiaries,  and  shall  not  be the  continuing  or  surviving
corporation of such  consolidation,  merger or amalgamation;  (ii) to permit any
person,  other than LaSalle or one of its  subsidiaries,  to merge or amalgamate
into Trenwick and Trenwick  shall be the  continuing  or surviving  corporation,
but, in connection with such merger or amalgamation, the then-outstanding shares
of Trenwick  Common Stock shall be changed into or exchanged  for stock or other
securities  of Trenwick or any other  person or cash or any other  property;  or
(iii) to sell or otherwise  transfer all or  substantially  all of its assets to
any person,  other than LaSalle or one of its  subsidiaries,  then,  and in each
such case, the agreement  governing such transaction shall make proper provision
so that  upon the  consummation  of such  transaction  and  upon the  subsequent
exercise of the Trenwick Option,  LaSalle shall be entitled to receive, for each
share of Trenwick Common Stock with respect to which the Trenwick Option has not
theretofore been exercised,  an amount of consideration in the form of and equal
to the per share amount of consideration that would be received by the holder of
one share of Trenwick  Common Stock (and, in the event of an election or similar
arrangement  with  respect to the type of  consideration  to be  received by the
holders of Trenwick  Common Stock,  subject to the foregoing,  proper  provision
shall be made so that the  holder of the  Trenwick  Option  would  have the same
election  or  similar  rights  as would the  holder  of the  number of shares of
Trenwick Common Stock for which the Trenwick Option is then exercisable).

                  10. Restrictive Legends. Each certificate  representing shares
of  Trenwick  Common  Stock  issued to LaSalle  at a Closing  will have typed or
printed thereon a restrictive legend in substantially the following form:

         THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
         UNDER THE SECURITIES  ACT OF 1933, AS AMENDED,  AND MAY BE REOFFERED OR
         SOLD ONLY IF SO  REGISTERED OR IF AN EXEMPTION  FROM SUCH  REGISTRATION
         IS  AVAILABLE.  SUCH   SECURITIES  ARE  ALSO   SUBJECT  TO   ADDITIONAL
         RESTRICTIONS  ON TRANSFER AS SET FORTH IN THE STOCK  OPTION  AGREEMENT,
         DATED  AS OF  DECEMBER  19,  1999,  A COPY OF  WHICH  MAY  BE  OBTAINED
         FROM THE ISSUER UPON REQUEST.

                  It is  understood  and agreed that:  (i) the  reference to the
resale  restrictions  of the Securities Act in the above legend shall be removed
by delivery of substitute  certificate(s)  without such reference if such Option
Shares have been  registered  pursuant to the Securities Act, such Option Shares
have  been  sold in  reliance  on and in  accordance  with  Rule 144  under  the
Securities  Act or LaSalle has delivered to Trenwick a copy of a letter from the
staff of the Securities and Exchange  Commission,  or an opinion of counsel,  in
form and substance  satisfactory to Trenwick and its counsel, to the effect that
such  legend is not  required  for  purposes  of the  Securities  Act;  (ii) the
reference to  restrictions  pursuant to this Agreement in the above legend shall
be removed by delivery of substitute  certificate(s)  without such  reference if
the Option Shares  evidenced by  certificate(s)  containing  such reference have
been sold or transferred in compliance with the provisions of this Agreement and
under  circumstances  that do not require the retention of such  reference;  and
(iii) the legend  shall be  removed in its  entirety  if the  conditions  in the
preceding  clauses  (i)  and  (ii)  are  both  satisfied.   In  addition,   such
certificate(s)  shall  bear  any  other  legend  as  may  be  required  by  law.
Certificates  representing  shares sold in a registered public offering pursuant
to Section 8 shall not be required to bear the legend set forth in this  Section
10.


                                       9
<PAGE>


                  11.  Profit Limitation.

                  (a)  Notwithstanding  any other provision of this Agreement or
the Business Combination Agreement, in no event shall LaSalle's Total Profit (as
hereinafter  defined) exceed $15 million (such amount,  the "Profit Limit") and,
if it would otherwise exceed such amount, LaSalle, at its sole election,  shall,
within five  business  days,  either (i) deliver to the Issuer for  cancellation
Option Shares (valued,  for purposes of this Section 11, at their closing market
price on the NYSE on the date of such delivery),  (ii) pay cash to the Issuer or
refund in cash any Trenwick Termination Fee previously paid to LaSalle or reduce
or waive the amount of any Trenwick  Termination Fee payable to LaSalle pursuant
to Section 7.4(b) of the Business Combination Agreement,  or (iii) undertake any
combination  thereof, so that LaSalle's Total Profit shall not exceed the Profit
Limit after taking into account the foregoing  actions.  As used herein,  "Total
Profit" means the aggregate amount (before taxes) of (i) $12 million, payable in
excess of  expenses,  pursuant  to Section  7.4(c) of the  Business  Combination
Agreement,  (ii)  amounts  paid by Trenwick  pursuant to Section 12 hereof,  and
(iii) (x) the net cash amounts received by LaSalle pursuant to the sale or other
disposition  of Option  Shares (or any other  securities  into which such Option
Shares are converted or exchanged) to any unaffiliated party, less (y) LaSalle's
purchase price for such Option Shares.

                  (b)  Notwithstanding  any other provision of this Agreement or
the Business Combination Agreement, the Trenwick Option may not be exercised for
a number of Option  Shares that would,  as of the date of the  Exercise  Notice,
result in a Notional  Total  Profit (as  hereinafter  defined)  of more than the
Profit Limit and, if exercise of the Trenwick Option  otherwise would exceed the
Profit Limit,  LaSalle,  at its discretion,  may increase the Exercise Price for
that  number  of Option  Shares  set  forth in the  Exercise  Notice so that the
Notional Total Profit shall not exceed the Profit Limit; provided,  that nothing
in this sentence  shall restrict any exercise of the Trenwick  Option  permitted
hereby on any  subsequent  date at the  Exercise  Price  set forth in  Section 1
hereof.  As used herein,  the term  "Notional  Total Profit" with respect to any
number of Option Shares as to which LaSalle may propose to exercise the Trenwick
Option  shall be the  Total  Profit  determined  as of the date of the  Exercise
Notice  assuming that the Trenwick  Option were  exercised on such date for such
number of Option Shares and assuming that such Option Shares,  together with all
other shares of Trenwick Common Stock held by LaSalle and its subsidiaries as of
such  date,  were sold for cash at the  closing  market  price for the  Trenwick
Common  Stock  on the  NYSE  Composite  Tape at the  close  of  business  on the
preceding trading day (less customary brokerage commissions).



                                       10

<PAGE>


                  12. Certain Repurchases.

                  (a) LaSalle  "Put".  Subject to the  limitations  set forth in
Section  11,  upon  delivery  of written  notice to  Trenwick  by  LaSalle  (the
"Repurchase Notice"):

                  (i)  at  any  time  during  which  the   Trenwick   Option  is
         exercisable pursuant to Section 2 (the "Repurchase  Period"),  Trenwick
         and its successors in interest shall repurchase from LaSalle all or any
         portion of the Trenwick Option, as specified by LaSalle,  at the Option
         Repurchase Price set forth in Section 12(b)(i); and

                  (ii) at any time  prior to the fifth  anniversary  of the date
         hereof,  Trenwick and its successors in interest shall  repurchase from
         LaSalle all or any portion of the Trenwick  Common  Stock  purchased by
         LaSalle  pursuant to the Trenwick Option,  as specified by LaSalle,  at
         the Share Repurchase Price set forth in Section 12(b)(iii).

                  (b)    Certain Definitions.   For purposes of this Section 12,
the following definitions shall apply:

                  (i) "Option  Repurchase  Price" shall mean (A) the  difference
         between the Option Repurchase Market/Offer Price (as defined below) for
         the Trenwick  Common Stock as of the date of the applicable  Repurchase
         Notice and the Exercise  Price,  multiplied by (B) the number of shares
         of Trenwick Common Stock purchasable pursuant to the Trenwick Option or
         the portion thereof covered by the applicable  Repurchase  Notice,  but
         only if the Option  Repurchase  Market/Offer  Price is greater than the
         Exercise Price.

                  (ii) "Option Repurchase  Market/Offer Price" shall mean, as of
         any date,  the higher of (X) the highest  price per share offered as of
         such date pursuant to any tender or exchange  offer or other offer with
         respect to a business  combination  offer involving  Trenwick or any of
         its material  subsidiaries  as the target party which was made prior to
         such date and not  terminated  or withdrawn as of such date and (Y) the
         Fair Market  Value (as  defined in Section  12(b)(v))  of the  Trenwick
         Common Stock as of such date.



                                       11
<PAGE>


                  (iii) "Share  Repurchase  Price" shall mean the product of (A)
         the sum of (I) the Exercise Price paid by LaSalle per share of Trenwick
         Common Stock acquired  pursuant to the Trenwick  Option and (II) if the
         Share Repurchase  Market/Offer Price (as defined below) is greater than
         the  Exercise  Price,  the  difference  between  the  Share  Repurchase
         Market/Offer  Price  and the  Exercise  Price,  and (B) the  number  of
         Trenwick Common Stock to be repurchased pursuant to this Section 12.

                  (iv) "Share Repurchase  Market/Offer  Price" shall mean, as of
         any date,  the  higher  of (X) the  highest  price  per  share  offered
         pursuant to a tender or exchange  offer or other  business  combination
         offer  involving  Trenwick as the target  party  during the  Repurchase
         Period prior to the delivery by LaSalle of a notice of  repurchase  and
         (Y) the Fair Market Value of the Trenwick Common Stock as of such date.

                  (v) "Fair  Market  Value"  shall  mean,  with  respect  to any
         security, the per share average of the last sale prices on the NYSE (or
         such other national  stock exchange or national  market system as shall
         then be the primary  trading market for such security) for the ten (10)
         trading days immediately preceding the applicable date.

                  (c) Payment  and  Redelivery  of Trenwick  Options or Trenwick
         Common Stock. In the event that LaSalle exercises its rights under this
         Section 12, Trenwick shall,  within ten (10) business days  thereafter,
         pay the required  amount to LaSalle in immediately  available funds and
         LaSalle  shall  surrender  to  Trenwick  the  Trenwick  Option  or  the
         certificate  or  certificates  evidencing  the  Trenwick  Common  Stock
         purchased by LaSalle pursuant hereto, and LaSalle shall warrant that it
         has sole  beneficial  ownership of the Trenwick Option or such Trenwick
         Common Stock and that the Trenwick Option or such Trenwick Common Stock
         are then free and clear of all claims, liens, charges, encumbrances and
         security interests of any nature whatsoever.

                  (d)  Repurchase  Price  Reduced at  LaSalle's  Option. In
         the event that  payment of the  repurchase  price  specified in Section
         12(a)  would  subject  the  repurchase  of the  Trenwick  Option or the
         Trenwick  Common Stock  purchased  by LaSalle  pursuant to the Trenwick
         Option to a vote of the stockholders of Trenwick pursuant to applicable
         law, regulations,  or requirements of a national securities exchange or
         national  market system or the Trenwick  By-Laws,  then LaSalle may, at
         its  election,  reduce  the  repurchase  price or the  number of shares
         covered by the  LaSalle  repurchase  request to an amount  which  would
         permit such repurchase without the necessity for such a vote.

                  (e)      Repurchase at the Election of Trenwick.



                                       12

<PAGE>

                  (i) Except to the extent that  LaSalle  shall have  previously
         exercised its rights under  Section  12(a),  at the written  request of
         Trenwick  during  the  six-month  period   immediately   following  the
         Repurchase  Period,  Trenwick may repurchase from LaSalle,  and LaSalle
         shall  sell to  Trenwick,  all (but not less than all) of the  Trenwick
         Common Stock  acquired by LaSalle  pursuant  hereto and with respect to
         which LaSalle has beneficial  ownership at the time of such repurchase,
         at a price  equal to the sum of (A) the  greater of (I) one hundred ten
         percent  (110%) of the  Current  Market  Price (as  defined  in Section
         12(e)(iii)) or (II) the sum of (X) the Purchase Price in respect of the
         shares so acquired plus (Y) LaSalle's Pre-Tax Carrying Cost (as defined
         in  Section  12(e)(iii)),  multiplied  in either  case by the number of
         shares so acquired, and (B) the amount of the documented  out-of-pocket
         expenses (to the extent not previously  reimbursed or  compensated  for
         pursuant  hereto or pursuant  to the  Business  Combination  Agreement)
         incurred  by  LaSalle  in  connection  with  the  Business  Combination
         Agreement and this Agreement and the transactions  contemplated thereby
         and hereby,  including  reasonable  accounting,  investment banking and
         legal fees (the "Section 12(e)  Repurchase  Consideration");  provided,
         that  Trenwick's  rights  under this  Section  12(e) shall be suspended
         (with any such rights  being  extended  accordingly)  during any period
         when the exercise of such rights would subject  LaSalle to liability or
         disgorgement of profits pursuant to Section 16(b) of the Exchange Act.

                  (ii) If  Trenwick  exercises  its rights  under  this  Section
         12(e),  Trenwick  shall,  within ten (10) business days pay the Section
         12(e)  Repurchase  Consideration  in  immediately  available  funds and
         LaSalle  shall  surrender  to  Trenwick  certificates   evidencing  the
         Trenwick Common Stock purchased hereunder with respect to which LaSalle
         then has  beneficial  ownership,  and LaSalle shall warrant that it has
         sole  beneficial  ownership of such Trenwick  Common Stock and that all
         such  shares  are then free and clear of all  claims,  liens,  charges,
         encumbrances and security interests of any nature whatsoever.

                  (iii) As used in Section 12(e)(i),  (A) "Current Market Price"
         shall mean the  average of the last sale  prices per share of  Trenwick
         Common  Stock on the NYSE for the ten  (10)  trading  days  immediately
         preceding the date of  Trenwick's  request for  repurchase  pursuant to
         this Section 12(e) and (B) "Pre-Tax Carrying Cost" shall mean an amount
         equal to the interest on the aggregate  purchase  price paid by LaSalle
         for the Trenwick Common Stock purchased pursuant to the Trenwick Option
         from the date of  purchase  to the  date of  repurchase  at the rate of
         interest  announced by  Citibank,  N.A. at its prime or base lending or
         reference rate during such period,  less any dividends  received on the
         shares so purchased, divided by the number of shares of Trenwick Common
         Stock so purchased.

                  13.   Binding   Effect;   No   Assignment;   No  Third   Party
Beneficiaries.  This Agreement shall be binding upon and inure to the benefit of
the  parties  hereto and their  respective  successors  and  permitted  assigns.
Neither this Agreement nor the rights or the  obligations of either party hereto
are  assignable,  except by operation of law, or with the written consent of the
other  party (it being  agreed  that all  transactions  contemplated  by Section
2.1(b) and (c) of the Business  Combination  Agreement  shall not be  considered
assignments  in  violation  of  this  Section  13).  Nothing  contained  in this
Agreement,  express or implied, is intended to confer upon any person other than
the parties hereto and their respective permitted assigns any rights or remedies
of any nature whatsoever by reason of this Agreement. Any Restricted Shares sold
by a  party  in  compliance  with  the  provisions  of  Section  8  shall,  upon
consummation of such sale, be free of the  restrictions  imposed with respect to
such shares by this Agreement,  unless and until such party shall  repurchase or
otherwise become the beneficial owner of such shares, and any transferee of such
shares shall not be entitled to the registration rights of such party.



                                       13

<PAGE>


                  14. Specific Performance. The parties recognize and agree that
if for any reason any of the  provisions of this  Agreement are not performed in
accordance  with their specific terms or are otherwise  breached,  immediate and
irreparable  harm or injury would be caused for which money damages would not be
an adequate  remedy.  Accordingly,  each party agrees that, in addition to other
remedies,  the other party shall be entitled to an  injunction  restraining  any
violation or threatened  violation of the provisions of this  Agreement.  In the
event that any action  should be brought in equity to enforce the  provisions of
the  Agreement,  neither  party will allege,  and each party  hereby  waives the
defense, that there is adequate remedy at law.

                  15. Entire Agreement. This Agreement, the Business Combination
Agreement (including any exhibits and schedules thereto) and the Confidentiality
Agreement  constitute  the  entire  agreement,  and  supersede  all other  prior
agreements and  understandings,  both written and oral, between the parties with
respect to the subject matter of this Agreement.

                  16.  Further  Assurances.  Each party will execute and deliver
all such further  documents and  instruments and take all such further action as
may be necessary in order to consummate the transactions contemplated hereby.

                  17.  Validity.  The  invalidity  or  unenforceability  of  any
provision of this Agreement shall not affect the validity or  enforceability  of
the other  provisions  of this  Agreement,  which shall remain in full force and
effect. In the event any court or other competent authority holds any provisions
of this Agreement to be null,  void or  unenforceable,  the parties hereto shall
negotiate  in good faith the  execution  and  delivery of an  amendment  to this
Agreement  in  order,  as nearly  as  possible,  to  effectuate,  to the  extent
permitted  by law,  the  intent  of the  parties  hereto  with  respect  to such
provision and the economic effects thereof.  If for any reason any such court or
regulatory  agency  determines that LaSalle is not permitted to acquire the full
number of shares of Trenwick  Common Stock  provided in Section 1 hereof (as the
same may be adjusted),  it is the express intention of Trenwick to allow LaSalle
to acquire  such  lesser  number of shares as may be  permissible,  without  any
amendment or modification  hereof.  Each party agrees that,  should any court or
other competent authority hold any provision of this Agreement or part hereof to
be  null,  void  or  unenforceable,  or  order  any  party  to take  any  action
inconsistent  herewith,  or not take any action required herein, the other party
shall not be entitled to specific  performance  of such provision or part hereof
or to any other remedy,  including but not limited to money damages,  for breach
hereof or of any other  provision of this Agreement or part hereof as the result
of such holding or order.


                                       14

<PAGE>


                  18. Notices. All notices,  requests, claims, demands and other
communications  under this  Agreement  shall be in  writing  and shall be deemed
given if (i) delivered,  personally,  or (ii) sent by overnight  courier service
(providing proof of delivery), or (iii) telecopied (which is confirmed), or (iv)
five (5) days after being mailed by registered or certified mail (return receipt
requested) to the parties at the  following  addresses (or at such other address
for a party as shall be specified by like notice):

                  If to Trenwick:

                           Alan L. Hunte
                           Vice President and
                              Chief Financial Officer
                           Trenwick Group Inc.
                           One Canterbury Green
                           Stamford, CT 06901
                           Fax: (203) 353-5550

                  with a copy to:

                           Baker & McKenzie
                           805 Third Avenue
                           New York, New York 10022
                           Attention: James R. Cameron
                           Fax: (212) 891-3835

                  If to LaSalle, to:

                           LaSalle Re Holdings Limited
                           Continental Building
                           25 Church Street
                           Hamilton HM 12
                           Bermuda
                           Fax: (441) 292-1501

                  with a copy to:

                           Mayer, Brown & Platt
                           190 S. LaSalle Street
                           Chicago, Illinois 60603
                           Attention: Richard W. Shepro
                           Fax: (312) 701-7711




                                       15
<PAGE>


                  19.  Governing Law;  Choice of Forum.  This Agreement shall be
governed by, and construed in accordance with, the laws of the State of Delaware
without regard to the conflicts of law principles  thereof.  Each of the parties
hereto (a) consents to submit itself to the personal jurisdiction of any federal
court located in the State of Delaware or any Delaware  state court in the event
any dispute arises out of this Agreement or any of the transactions contemplated
by this  Agreement,  (b) agrees  that it will not attempt to deny or defeat such
personal  jurisdiction  by motion or other request for leave from any such court
and (c) agrees that it will not bring any action  relating to this  Agreement or
any of the transactions contemplated by this Agreement in any court other than a
federal court sitting in the state of Delaware or a Delaware state court.

                  20. Interpretation. When a reference is made in this Agreement
to a Section,  such  reference  shall be to a Section of this  Agreement  unless
otherwise indicated. Whenever the words "include", "includes" or "including" are
used in this  Agreement,  they  shall be  deemed  to be  followed  by the  words
"without   limitation."  The  descriptive   headings  herein  are  inserted  for
convenience  of  reference  only and are not intended to be part of or to affect
the meaning or interpretation of this Agreement.

                  21.  Counterparts.  This  Agreement  may be executed in one or
more counterparts,  each of which shall be deemed to be an original, but both of
which, taken together, shall constitute one and the same instrument.

                  22. Expenses. Except as otherwise expressly provided herein or
in the  Business  Combination  Agreement,  all costs and  expenses  incurred  in
connection with the transactions contemplated by this Agreement shall be paid by
the party incurring such expenses.

                  23. Amendment. This Agreement may not be amended, except by an
instrument in writing signed on behalf of each of the parties.

                  24. Waiver.  Any agreement on the part of a party to waive any
provision  of this  Agreement,  or to extend the time for  performance,  will be
valid only if set forth in an  instrument  in  writing  signed on behalf of such
party.  The failure of any party to this  Agreement  to assert any of its rights
under this Agreement or otherwise will not constitute a waiver of such rights.




                                       16

<PAGE>


                  25. Loss or  Mutilation.  Upon receipt by Trenwick of evidence
reasonably  satisfactory to it of the loss, theft,  destruction or mutilation of
this  Agreement,  and (in the case of loss,  theft or destruction) of reasonably
satisfactory  indemnification,  and  upon  surrender  and  cancellation  of this
Agreement,  if  mutilated,  Trenwick  will  execute and deliver to LaSalle a new
Agreement of like tenor and date. Any such new Agreement  executed and delivered
will  constitute an additional  contractual  obligation on the part of Trenwick,
whether or not the Agreement so lost, stolen,  destroyed,  or mutilated shall at
any time be enforceable by anyone.

                  26. Extension of Time Periods.  The time periods for exercises
of certain rights  hereunder shall be extended (but in no event by more than six
(6) months):  (a) to the extent necessary to obtain all  governmental  approvals
for the exercise of such rights, and for the expiration of all statutory waiting
periods;  and (b) to the extent necessary to avoid any liability or disgorgement
of profits under Section 16(b) of the Exchange Act by reason of such exercise.

                  27.  Further  Assurance.  Each  party  agrees to  execute  and
deliver all such further  documents  and  instruments  and take all such further
action as may be necessary in order to consummate the transactions  contemplated
hereby.











                                       17

<PAGE>


                  IN WITNESS  WHEREOF,  the  parties  hereto  have  caused  this
Agreement to be executed by their respective duly authorized  officers as of the
date first above written.

                                    TRENWICK GROUP INC.


                                    By: /s/ James F. Billett, Jr.
                                        ----------------------------------
                                        Name:  James F. Billett, Jr.
                                        Title: Chairman, President and Chief
                                               Executive Officer


                                    LASALLE RE HOLDINGS LIMITED


                                    By: /s/ Guy D. Hengesbaugh
                                        ----------------------------------
                                        Name:  Guy D. Hengesbaugh
                                        Title: President and Chief Executive
                                               Officer







                         TRENWICK STOCK OPTION AGREEMENT

                  STOCK  OPTION  AGREEMENT,  dated as of December  19, 1999 (the
"Agreement")  by  and  between  Trenwick  Group  Inc.,  a  Delaware  corporation
("Trenwick"),  and LaSalle Re Holdings  Limited,  a company  organized under the
laws of Bermuda ("LaSalle" or the "Issuer").

                  WHEREAS,  concurrently with the execution and delivery of this
Agreement,  LaSalle,  LaSalle Re Limited,  a company organized under the laws of
Bermuda,  Trenwick,  Trenwick Group (Delaware) Inc., a Delaware  corporation and
Gowin Holdings  International  Limited,  a company  organized  under the laws of
Bermuda ("New Holdings"), are entering into an Agreement, Scheme of Arrangement,
Plan of Merger,  and Plan of  Reorganization  dated as of the date  hereof  (the
"Business Combination Agreement"); and

                  WHEREAS,  as a condition to  Trenwick's  willingness  to enter
into the Business  Combination  Agreement,  Trenwick has requested  that LaSalle
agree, and LaSalle has so agreed,  to grant to Trenwick an option to purchase up
to 3,105,110  common  shares,  par value $1.00 per share,  of LaSalle  ("LaSalle
Common  Shares") in accordance  with the terms and subject to the conditions set
forth herein.

                  NOW, THEREFORE,  to induce Trenwick to enter into the Business
Combination  Agreement,  and in  consideration  of the  foregoing and the mutual
representations,  warranties,  covenants and  agreements set forth herein and in
the  Business  Combination  Agreement,  the  parties  hereto  agree as  follows.
Capitalized  terms used herein but not defined  herein  shall have the  meanings
ascribed to them in the Business Combination Agreement.

                  1. Grant of Option.  Subject to the terms and  conditions  set
forth  herein,  LaSalle  hereby  grants to Trenwick an  irrevocable  option (the
"LaSalle  Option") to purchase up to 3,105,110 (as adjusted as set forth herein)
shares (the  "Option  Shares") of LaSalle  Common  Shares (such number of Option
Shares representing 19.9% of the LaSalle Common Shares issued and outstanding on
the date hereof) in the manner set forth below at a price (the "Exercise Price")
of $12.81 per Option Share (which price per share is equal to the average of the
last  sale  prices  of  LaSalle  Common  Shares  on the ten  (10)  trading  days
immediately prior to the date of public announcement of the Business Combination
Agreement,  payable in cash or by cashless exercise in accordance with Section 4
hereof.  Notwithstanding  the foregoing,  in no event shall the number of Option
Shares for which the LaSalle Option is exercisable exceed 19.9% of the number of
issued and outstanding shares of LaSalle Common Shares.

                  2.  Exercise of Option. The LaSalle Option may be exercised by
Trenwick,  in whole  or in part,  at any  time or from  time to time  after  the
Business   Combination   Agreement   becomes   terminable   by  Trenwick   under
circumstances  which  would or could  entitle  Trenwick  to receive  the LaSalle



<PAGE>

Termination Fee pursuant to Section 7.4(c) of the Business Combination Agreement
(a "Trigger Event") (regardless of whether the Business Combination Agreement is
actually terminated or whether there occurs a closing involving LaSalle). In the
event Trenwick wishes to exercise the LaSalle Option,  Trenwick shall deliver to
LaSalle a written notice (an "Exercise  Notice")  specifying the total number of
Option  Shares it wishes to purchase and whether such  exercise is in cash or by
cashless  exercise  in  accordance  with  Section 4 hereof.  Each  closing  of a
purchase of Option Shares (an "Option  Closing") shall occur, but subject to the
satisfaction  or waiver of the  conditions  set forth in Section 3 hereof,  at a
place,  on a date and at a time  designated  by Trenwick  in an Exercise  Notice
delivered  at least  two (2)  business  days  prior  to the  date of the  Option
Closing.  The  LaSalle  Option  shall  terminate  upon the  earlier  of: (i) the
Effective Time; (ii) the termination of the Business Combination Agreement other
than under  circumstances  which also  constitute a Trigger Event;  or (iii) the
180th day  following a Trigger  Event (or if, at the  expiration of such 180 day
period  the  LaSalle  Option  cannot be  exercised  by reason of any  applicable
judgment,  decree,  order, law or regulation,  ten (10) business days after such
impediment  to exercise  shall have been  removed or shall have become final and
not subject to appeal,  but in no event  under this clause  (iii) later than the
365th day following such Trigger  Event).  Notwithstanding  the  foregoing,  the
LaSalle Option may not be exercised if Trenwick is in material  breach of any of
its representations or warranties, or in material breach of any of its covenants
or  agreements,  contained  in this  Agreement  or in the  Business  Combination
Agreement. Upon the giving by Trenwick to LaSalle of the Exercise Notice and the
tender  of  the  applicable   aggregate  Exercise  Price,  but  subject  to  the
satisfaction or waiver of the conditions set forth in Section 3 hereof, Trenwick
shall be deemed to be the holder of record of the Option  Shares  issuable  upon
such  exercise,  notwithstanding  that the stock transfer books of LaSalle shall
then be closed or that  certificates  representing  such Option Shares shall not
then be actually delivered to Trenwick.

                  3.  Conditions to Closing.  The obligation of LaSalle to issue
the Option  Shares to Trenwick  hereunder  is subject to the  conditions,  which
(other than the  conditions  described in clauses (i), (iii) and (iv) below) may
be waived by LaSalle in its sole discretion,  that (i) all waiting  periods,  if
any,  under  the HSR  Act,  applicable  to the  issuance  of the  Option  Shares
hereunder  shall have expired or have been  terminated;  (ii) the Option  Shares
shall  have  been  approved  for  listing  on the NYSE upon  official  notice of
issuance;  (iii)  all  consents,  approvals,  orders  or  authorizations  of, or
registrations,  declarations  or  filings  with,  any  federal,  state  or local
administrative   agency  or  commission  or  other   federal,   state  or  local
Governmental  Authority,  including  without  limitation,  the Bermuda  Monetary
Authority, if any, required in connection with the issuance of the Option Shares
hereunder  shall  have  been  obtained  or made,  as the case may be  including,
without limitation, by Trenwick; and (iv) no preliminary or permanent injunction
or  other  order  or  decree  by any  court of  competent  jurisdiction,  law or
regulation  prohibiting  or  otherwise  restraining  such  issuance  shall be in
effect.


                                       2

<PAGE>


                  4.      Payment and Delivery of Certificates.

                  (a)     At any Option Closing, Trenwick  shall pay to LaSalle
the  aggregate  purchase  price (equal to the Exercise  Price  multiplied by the
number of Option  Shares to be purchased at such Option  Closing) for the shares
of LaSalle  Common  Shares  purchased  pursuant  to the  exercise of the LaSalle
Option  in  immediately  available  funds  by wire  transfer  to a bank  account
designated in writing by LaSalle; provided,  however, that failure or refusal of
LaSalle to designate  such account shall not preclude  Trenwick from  exercising
the  LaSalle  Option.  At  Trenwick's  option,  in lieu of  delivering  the cash
Exercise  Price,  Trenwick  may  instruct  LaSalle in writing to deduct from the
number of shares of LaSalle  Common  Shares that would  otherwise be issued upon
such exercise, a number of shares of LaSalle Common Shares equal to the quotient
obtained from dividing:

                  (x) the  product  obtained  by  multiplying  (1) the number of
         shares of LaSalle  Common Shares for which the LaSalle  Option is being
         exercised and (2) the Exercise Price then in effect, by

                  (y) the Fair Market Value of a share of LaSalle Common Shares.

"Fair Market Value" shall have the meaning specified in Section 12(b)(v).

                  (b)   At any Option Closing, simultaneously with the delivery
of immediately available funds as provided in Section 4(a), LaSalle will deliver
to Trenwick a certificate or certificates representing the number of Option
Shares to be purchased by Trenwick at such Option  Closing,  which Option Shares
will be free and clear of all liens,  claims,  charges and  encumbrances  of any
kind  whatsoever  and if the option is  exercised  in part only,  LaSalle  shall
deliver a new option  evidencing the rights of Trenwick  thereof to purchase the
balance of the shares  purchasable  hereunder  and (ii) Trenwick will deliver to
LaSalle a copy of this  Agreement  and a letter  agreeing that Trenwick will not
offer to sell or otherwise dispose of such shares in violation of applicable law
or the provisions of this Agreement. LaSalle shall pay all expenses, and any and
all United States  federal,  state and local taxes and other charges that may be
payable  in  connection  with  the  preparation,  issue  and  delivery  of stock
certificates  under  this  Section 4 in the name of  Trenwick  or its  designee.
LaSalle shall use its reasonable best efforts to cause the LaSalle Common Shares
being delivered at the Option Closing to be approved for listing on the NYSE and
shall pay all expenses in connection  with the  application for approval and the
listing of such shares.

                  5.  Representations and Warranties of LaSalle.  LaSalle hereby
represents  and  warrants  to  Trenwick  that  (a)  LaSalle  is a  company  duly
organized,  validly  existing and in good standing under the laws of Bermuda and
has the  corporate  power and  authority to enter into this  Agreement,  (b) the
execution  and  delivery of this  Agreement by LaSalle and the  consummation  by
LaSalle of the transactions contemplated hereby have been duly authorized by all


                                       3

<PAGE>

necessary  corporate  action  on the  part of  LaSalle  and no  other  corporate
proceedings  on the part of LaSalle are necessary to authorize this Agreement or
any of the transactions  contemplated  hereby,  (c) this Agreement has been duly
executed and delivered by LaSalle, constitutes a valid and binding obligation of
LaSalle and, assuming this Agreement  constitutes a valid and binding obligation
of Trenwick,  is enforceable  against LaSalle in accordance with its terms,  (d)
LaSalle has taken all  necessary  corporate  action to authorize and reserve for
issuance and to permit it to issue, upon exercise of the LaSalle Option,  and at
all times from the date hereof through the expiration of the LaSalle Option will
have  reserved,  3,105,110  authorized and unissued  Option Shares,  such amount
being subject to  adjustment as provided in Section 9, all of which,  upon their
issuance and delivery in accordance  with the terms of this  Agreement,  will be
validly issued,  fully paid and  nonassessable,  (e) upon delivery of the Option
Shares to  Trenwick  upon the  exercise  of the LaSalle  Option,  Trenwick  will
acquire  the  Option  Shares  free and  clear  of all  claims,  liens,  charges,
encumbrances  and  security  interests  of any  nature  whatsoever,  (f) none of
LaSalle,  any of its  affiliates  or anyone  acting on its or their  behalf  has
issued,   sold  or  offered  any   security  of  LaSalle  to  any  person  under
circumstances  that would cause the issuance and sale of the Option  Shares,  as
contemplated by this Agreement,  to be subject to the registration  requirements
of the  Securities  Act as in  effect  on the  date  hereof  and,  assuming  the
representations  of Trenwick  contained in Section 6(d) are true and correct and
based on Trenwick's  commitment  in its letter  referred to in Section 4 hereof,
the issuance,  sale and delivery of the Option Shares  hereunder would be exempt
from the  registration  and prospectus  delivery  requirements of the Securities
Act,  as in effect on the date  hereof  (and  LaSalle  shall not take any action
which would cause the issuance, sale and delivery of the Option Shares hereunder
not to be exempt from such requirements),  and (g) the execution and delivery of
this Agreement by LaSalle does not, and,  subject to compliance  with applicable
law, the  consummation by LaSalle of the transactions  contemplated  hereby will
not,  violate,  conflict  with,  or result in a breach of any  provision  of, or
constitute a default (with or without notice or a lapse of time, or both) under,
or result in the termination  of, or accelerate the performance  required by, or
result  in  a  right  of  termination,  cancellation,  or  acceleration  of  any
obligation or the loss of a material  benefit under,  or the creation of a lien,
pledge,  security  interest or other  encumbrance on assets (any such violation,
conflict,  breach,  default,  termination,  acceleration,  right of termination,
cancellation or  acceleration,  loss, or creation,  a "Violation") of LaSalle or
any of its subsidiaries,  pursuant to (i) any provision of the LaSalle Bye-Laws,
(ii) any provision of any material  loan or credit  agreement,  note,  mortgage,
indenture,  lease,  benefit  plan or other  agreement,  obligation,  instrument,
permit,  concession,  franchise or license (a "Material Contract") of LaSalle or
any of its  subsidiaries  or to which  any of them is a party or by which any of
them or their  properties  or assets are bound,  or (iii) any  judgment,  order,
decree, statute, law, ordinance, rule or regulation applicable to LaSalle or any
of its  subsidiaries  or any of their  respective  properties  or assets,  which
Violation,  in the case of each of clauses  (ii) or (iii),  would have  Material
Adverse Effect on LaSalle.

                  6.  Representations  and  Warranties  of  Trenwick.   Trenwick
represents  and  warrants to LaSalle  that (a)  Trenwick is a  corporation  duly



                                       4


<PAGE>

organized,  validly existing and in good standing under the laws of the State of
Delaware and has the corporate  power and authority to enter into this Agreement
and to carry out its  obligations  hereunder,  (b) the execution and delivery of
this Agreement by Trenwick and the  consummation by Trenwick of the transactions
contemplated  hereby have been duly authorized by all necessary corporate action
on the  part of  Trenwick  and no  other  corporate  proceedings  on the part of
Trenwick are necessary to authorize  this  Agreement or any of the  transactions
contemplated  hereby, (c) this Agreement has been duly executed and delivered by
Trenwick  and  constitutes  a valid and binding  obligation  of  Trenwick,  and,
assuming this Agreement  constitutes a valid and binding  obligation of LaSalle,
is enforceable against Trenwick in accordance with its terms, and (d) any Option
Shares  acquired  upon  exercise  of the LaSalle  Option  will be  acquired  for
Trenwick's own account,  for  investment  purposes only and will not be, and the
LaSalle  Option is not being,  acquired  by  Trenwick  with a view to the public
distribution  thereof in violation of any applicable provision of the Securities
Act, and (e) the execution and delivery of this  Agreement by Trenwick does not,
and,  subject to compliance with applicable law, the consummation by Trenwick of
the transactions contemplated hereby will not, violate, conflict with, or result
in the breach of any  provision  of, or  constitute  a default  (with or without
notice  or a lapse of time,  or both)  under,  or  result  in any  Violation  by
Trenwick  or any of its  subsidiaries,  pursuant  to (i)  any  provision  of the
certificate of incorporation or by-laws of Trenwick,  (ii) any Material Contract
of Trenwick or any of its  subsidiaries or to which any of them is a party or by
which any of them or any of their  properties or assets are bound,  or (iii) any
judgment,  order, decree, statute, law, ordinance, rule or regulation applicable
to Trenwick,  any of its subsidiaries or any of their  respective  properties or
assets,  which  Violation,  in the case of each of clauses (ii) or (iii),  would
have a Material Adverse Effect on Trenwick.

                  7.   Restrictions on Transfer.

                  (a)  Restrictions on Transfer.  Prior to the first anniversary
of the date on  which  Trenwick  purchases  any  Option  Shares  hereunder  (the
"Expiration Date"), Trenwick shall not, directly or indirectly,  by operation of
law or otherwise,  sell, assign, pledge, or otherwise dispose of or transfer any
Option  Shares  acquired by Trenwick  pursuant  to this  Agreement  ("Restricted
Shares")  beneficially  owned by it, other than in accordance with Section 7(b),
7(c) or  Section 8.  Subsequent  to the  Expiration  Date,  Trenwick  shall not,
directly or indirectly,  by operation of law or otherwise,  sell, assign, pledge
or otherwise dispose of or transfer any Restricted Shares  beneficially owned by
it  to  any  purchaser,   assignee,  pledgee  or  other  transferee  who  would,
immediately  after such  sale,  assignment,  pledge,  disposition  or  transfer,
beneficially  own more than  4.9% of the then  outstanding  voting  power of the
Issuer of the Restricted Shares, except in accordance with Section 7(b), 7(c) or
Section 8 and other than in market transactions at prevailing prices.

                  (b) Permitted Sales. Following the termination of the Business
Combination  Agreement,  Trenwick  shall be  permitted  to sell or transfer  any
Restricted  Shares  beneficially  owned by it if such sale is made pursuant to a
tender or exchange  offer or merger that has been  approved or  recommended,  or
otherwise determined to be fair to and in the best interests of the shareholders
of LaSalle,  by a majority of the members of the Board of  Directors  of LaSalle
(which  majority shall include a majority of directors who were directors  prior
to the announcement of such tender or exchange offer or merger).




                                       5

<PAGE>


                  (c)  LaSalle's  Right of First Refusal.  At any time after the
first  occurrence of a Trigger Event and prior to the  expiration of twenty-four
(24) months  immediately  following the first  purchase of LaSalle Common Shares
pursuant  to the  LaSalle  Option,  if Trenwick  shall  desire to sell,  assign,
transfer or otherwise  dispose of any shares of LaSalle  Common  Shares or other
securities  acquired by it pursuant to the LaSalle  Option,  Trenwick shall give
LaSalle written notice of the proposed  transaction (a "Trenwick Offer Notice"),
identifying the proposed transferee, accompanied by a copy of a binding offer to
purchase  such  LaSalle  Common  Shares  or  other  securities  signed  by  such
transferee and setting forth the terms of the proposed  transaction.  A Trenwick
Offer  Notice  shall be deemed an offer by Trenwick  to  LaSalle,  which must be
accepted,  if at all,  within  five (5)  business  days of the  receipt  of such
Trenwick Offer Notice, on the same terms and conditions and at the same price at
which  Trenwick is proposing to transfer  such  LaSalle  Common  Shares or other
securities  to such  transferee.  The purchase of any LaSalle  Common  Shares or
other  securities by LaSalle  shall be settled  within five (5) business days of
the date of the  acceptance of the offer and the purchase price shall be paid to
Trenwick in immediately  available funds. In the event of the failure or refusal
of LaSalle to purchase  all of the  LaSalle  Common  Shares or other  securities
covered by a Trenwick  Offer  Notice,  Trenwick  may sell all, but not less than
all,  of  such  LaSalle  Common  Shares  or  other  securities  to the  proposed
transferee  at a price no less  than the  price  specified  and on terms no more
favorable to the  transferee  than those set forth in the Trenwick Offer Notice;
provided  that the  provisions  of this  sentence  shall not  limit  the  rights
Trenwick  may  otherwise  have in the  event  LaSalle  has  accepted  the  offer
contained in the Trenwick  Offer Notice and  wrongfully  refuses to purchase the
LaSalle Common Shares or other securities  subject thereto.  The requirements of
this  Section 7(c) shall not apply to (i) any  disposition  as a result of which
the proposed  transferee would not beneficially own more than three percent (3%)
of the  outstanding  voting power of LaSalle,  (ii) any  disposition  of LaSalle
Common Shares or other  securities by a person to whom Trenwick has assigned its
rights under the LaSalle  Option with the consent of LaSalle,  (iii) any sale by
means of a public  offering  registered  under the  Securities  Act, or (iv) any
transfer to a wholly-owned  subsidiary of Trenwick which agrees in writing to be
bound by the terms hereof.

                  8.   Registration  Rights.  Following the  termination  of the
Business Combination Agreement, but not later than the second anniversary of the
last date that Trenwick  acquired Option Shares under this  Agreement,  Trenwick
may by written notice (the "Registration  Notice") to LaSalle request LaSalle to
register  under  the  Securities  Act all or any part of the  Restricted  Shares
beneficially owned by Trenwick (the  "Registrable  Securities") pursuant  to   a
bona fide firm commitment underwritten public offering in which Trenwick and the
underwriters shall effect as wide a distribution of such Registrable  Securities
as is reasonably practicable and shall use their commercially reasonable efforts




                                       6

<PAGE>

to prevent  any  person  (including  any Group (as used in Rule 13d-5  under the
Exchange  Act))  and  its  affiliates  from  purchasing  through  such  offering
Restricted  Shares  representing  more than one percent (1%) of the  outstanding
shares  of  common  stock of  LaSalle  on a fully  diluted  basis (a  "Permitted
Offering").  The  Registration  Notice shall include a  certificate  executed by
Trenwick and its proposed  managing  underwriter,  which underwriter shall be an
investment  banking firm of  nationally  recognized  standing  (the  "Manager"),
stating  that (i) they  have a good  faith  intention  to  commence  promptly  a
Permitted  Offering and (ii) the Manager in good faith believes  that,  based on
the then prevailing market  conditions,  it will be able to sell the Registrable
Securities  at a per share price equal to at least eighty  percent  (80%) of the
then Fair Market Value (as defined  below) of such shares.  LaSalle  (and/or any
person  designated by LaSalle) shall  thereupon  have the option  exercisable by
written  notice  delivered to Trenwick  within five (5) business  days after the
receipt of the Registration Notice,  irrevocably to agree to purchase all or any
part of the  Registrable  Securities  proposed to be so sold for cash at a price
(the  "Option  Price")  equal to the  product of (i) the  number of  Registrable
Securities  to be so purchased by LaSalle and (ii) the then Fair Market Value of
such shares.  Any such  purchase of  Registrable  Securities  by LaSalle (or its
designee)  hereunder  shall take place at a closing to be held at the  principal
executive  offices of LaSalle or at the offices of its counsel at any reasonable
date and time  designated by LaSalle  and/or such designee in such notice within
twenty (20)  business  days after  delivery of such notice.  Any payment for the
shares to be purchased  shall be made by delivery at the time of such closing of
the Option Price in  immediately  available  funds.  As used  herein,  the "Fair
Market Value" of any share shall be the average of the daily closing sales price
for such share on the NYSE  during the ten (10) NYSE  trading  days  immediately
preceding the date such Fair Market Value is to be determined.

                  If LaSalle does not elect to exercise  its option  pursuant to
this  Section 8 with  respect to all  Registrable  Securities,  it shall use its
commercially  reasonable  efforts to effect,  as  promptly as  practicable,  the
registration under the Securities Act of the unpurchased  Registrable Securities
proposed  to be so sold;  provided,  however,  that (i)  Trenwick  shall  not be
entitled to more than an  aggregate  of two  effective  registration  statements
hereunder  and (ii) LaSalle  will not be required to file any such  registration
statement  during any period of time (not to exceed  ninety (90) days after such
request in the case of clauses  (A),  (B) or (C) below)  when (A)  LaSalle is in
possession of material non-public information which it reasonably believes would
be  detrimental  to be  disclosed at such time and, in the opinion of counsel to
LaSalle, such information would have to be disclosed if a registration statement
were filed at that time;  (B) LaSalle is required  under the  Securities  Act to
include  audited  financial  statements  for any  period  in  such  registration
statement and such  financial  statements are not yet available for inclusion in
such  registration  statement;  or (C)  LaSalle  determines,  in its  reasonable
judgment, that such registration would interfere with any financing, acquisition
or  other  material  transaction  involving  LaSalle  or any of its  affiliates.
LaSalle  shall  use  its  reasonable  best  efforts  to  cause  any  Registrable
Securities  registered pursuant to this Section 8 to be qualified for sale under
the securities or blue sky laws of such jurisdictions as Trenwick may reasonably
request and shall continue such  registration or qualification in effect in such
jurisdiction;  provided,  however, that LaSalle shall not be required to qualify
to do business in, or consent to general service of process in, any jurisdiction
by reason of this provision.



                                       7

<PAGE>


                  The  registration  rights  set  forth  in this  Section  8 are
subject  to  the  condition  that  Trenwick  shall  provide  LaSalle  with  such
information with respect to such holder's Registrable Securities,  the plans for
the distribution thereof, and such other information with respect to such holder
as, in the  reasonable  judgment of counsel for LaSalle,  is necessary to enable
LaSalle to include in such registration statement all material facts required to
be disclosed with respect to a registration thereunder.

                  A registration effected under this Section 8 shall be effected
at LaSalle's expense,  except for underwriting discounts and commissions and the
fees and the expenses of counsel to Trenwick,  and LaSalle  shall provide to the
underwriters such documentation (including certificates, opinions of counsel and
"comfort"   letters  from   auditors)  as  are  customary  in  connection   with
underwritten  public offerings as such underwriters may reasonably  require.  In
connection with any such  registration,  the parties agree (i) to indemnify each
other and the underwriters in the customary manner (provided that Trenwick shall
only be required to indemnify other parties to such  underwriting  agreement for
information  relating to such  Trenwick and supplied by it for inclusion in such
registration  statement),  (ii) to enter into an underwriting  agreement in form
and substance  customary for  transactions of such type with the Manager and the
other underwriters  participating in such offering and (iii) to take all further
actions which shall be reasonably necessary to effect such registration and sale
(including,  if the  Manager  deems it  necessary,  participating  in road  show
presentations).

                  LaSalle   shall  be  entitled  to  include  (at  its  expense)
additional  shares of its common stock in a  registration  effected  pursuant to
this  Section  8 only if and to the  extent  the  Manager  determines  that such
inclusion will not adversely affect the prospects for success of such offering.

                  9.   Adjustment  upon Changes in  Capitalization.  (a) Without
limitation to any  restriction on LaSalle  contained in this Agreement or in the
Business  Combination  Agreement,  in the event of any change in LaSalle  Common
Shares  by  reason  of  stock  dividends,   split-ups,  mergers,  amalgamations,
recapitalizations,  subdivisions,  conversions, combinations, exchange of shares
or the like, the type and number of shares or securities  subject to the LaSalle
Option,  and the Exercise Price per Option Share provided in Section 1, shall be
adjusted  appropriately to restore to Trenwick its rights  hereunder,  including
the right to purchase  from the LaSalle  (or its  successors)  shares of LaSalle
Common Shares  representing  19.9% of the outstanding  LaSalle Common Shares for
the aggregate  Exercise  Price  calculated  as of the date of this  Agreement as
provided in Section 1.


                                       8

<PAGE>


                  (b) In the event that LaSalle  shall enter into an  agreement:
(i) to consolidate with merge or amalgamate into any person, other than Trenwick
or one of its  subsidiaries,  and  shall  not  be the  continuing  or  surviving
corporation of such  consolidation,  merger or amalgamation;  (ii) to permit any
person,  other than Trenwick or one of its subsidiaries,  to merge or amalgamate
into LaSalle and LaSalle shall be the continuing or surviving corporation,  but,
in connection with such merger or amalgamation,  the then-outstanding  shares of
LaSalle  Common  Shares shall be changed  into or  exchanged  for stock or other
securities  of LaSalle  or any other  person or cash or any other  property;  or
(iii) to sell or otherwise  transfer all or  substantially  all of its assets to
any person,  other than Trenwick or one of its  subsidiaries,  then, and in each
such case, the agreement  governing such transaction shall make proper provision
so that  upon the  consummation  of such  transaction  and  upon the  subsequent
exercise of the LaSalle Option,  Trenwick shall be entitled to receive, for each
share of LaSalle  Common Shares with respect to which the LaSalle Option has not
theretofore been exercised,  an amount of consideration in the form of and equal
to the per share amount of consideration that would be received by the holder of
one share of LaSalle  Common Shares (and, in the event of an election or similar
arrangement  with  respect to the type of  consideration  to be  received by the
holders of LaSalle Common Shares,  subject to the  foregoing,  proper  provision
shall be made so that the  holder  of the  LaSalle  Option  would  have the same
election  or  similar  rights  as would the  holder  of the  number of shares of
LaSalle Common Shares for which the LaSalle Option is then exercisable).



                  10. Restrictive Legends. Each certificate  representing shares
of LaSalle  Common  Shares  issued to Trenwick  at a Closing  will have typed or
printed thereon a restrictive legend in substantially the following form:

         THE   SECURITIES  REPRESENTED  BY  THIS  CERTIFICATE  HAVE  NOT  BEEN
         REGISTERED  UNDER THE SECURITIES ACT OF 1933, AS AMENDED,  AND  MAY  BE
         REOFFERED  OR  SOLD  ONLY IF SO REGISTERED  OR IF  AN  EXEMPTION   FROM
         SUCH  REGISTRATION  IS AVAILABLE.  SUCH  SECURITIES ARE ALSO SUBJECT TO
         ADDITIONAL  RESTRICTIONS  ON TRANSFER AS SET FORTH IN THE STOCK  OPTION
         AGREEMENT,  DATED AS OF  DECEMBER  19,  1999,  A COPY OF  WHICH  MAY BE
         OBTAINED FROM THE ISSUER UPON REQUEST.

                  It is  understood  and agreed that:  (i) the  reference to the
resale  restrictions  of the Securities Act in the above legend shall be removed
by delivery of substitute  certificate(s)  without such reference if such Option
Shares have been  registered  pursuant to the Securities Act, such Option Shares
have  been  sold in  reliance  on and in  accordance  with  Rule 144  under  the
Securities  Act or Trenwick has delivered to LaSalle a copy of a letter from the
staff of the Securities and Exchange  Commission,  or an opinion of counsel,  in
form and substance  satisfactory to LaSalle and its counsel,  to the effect that
such  legend is not  required  for  purposes  of the  Securities  Act;  (ii) the
reference to  restrictions  pursuant to this Agreement in the above legend shall
be removed by delivery of substitute  certificate(s)  without such  reference if
the Option Shares  evidenced by  certificate(s)  containing  such reference have
been sold or transferred in compliance with the provisions of this Agreement and
under  circumstances  that do not require the retention of such  reference;  and
(iii) the legend  shall be  removed in its  entirety  if the  conditions  in the
preceding  clauses  (i)  and  (ii)  are  both  satisfied.   In  addition,   such
certificate(s)  shall  bear  any  other  legend  as  may  be  required  by  law.
Certificates  representing  shares sold in a registered public offering pursuant
to Section 8 shall not be required to bear the legend set forth in this  Section
10.


                                       9

<PAGE>

                  11.  Profit Limitation.

                  (a)  Notwithstanding  any other provision of this Agreement or
the Business  Combination  Agreement,  in no event shall Trenwick's Total Profit
(as hereinafter  defined)  exceed $15 million (such amount,  the "Profit Limit")
and, if it would otherwise exceed such amount,  Trenwick,  at its sole election,
shall,  within  five  business  days,  either  (i)  deliver  to the  Issuer  for
cancellation  Option Shares  (valued,  for purposes of this Section 11, at their
closing market price on the NYSE on the date of such delivery), (ii) pay cash to
the Issuer or refund in cash any  LaSalle  Termination  Fee  previously  paid to
Trenwick or reduce or waive the amount of any LaSalle Termination Fee payable to
Trenwick pursuant to Section 7.4(c) of the Business  Combination  Agreement,  or
(iii) undertake any combination  thereof,  so that Trenwick's Total Profit shall
not exceed the Profit Limit after taking into account the foregoing actions.  As
used herein, "Total Profit" means the aggregate amount (before taxes) of (i) $12
million,  payable  in excess of  expenses,  pursuant  to  Section  7.4(c) of the
Business Combination Agreement, (ii) amounts paid by LaSalle pursuant to Section
12 hereof and (iii) (x) the net cash  amounts  received by Trenwick  pursuant to
the sale or other  disposition  of Option Shares (or any other  securities  into
which such Option Shares are converted or exchanged) to any unaffiliated  party,
less (y) Trenwick's purchase price for such Option Shares.

                  (b)  Notwithstanding  any other provision of this Agreement or
the Business Combination Agreement,  the LaSalle Option may not be exercised for
a number of Option  Shares that would,  as of the date of the  Exercise  Notice,
result in a Notional  Total  Profit (as  hereinafter  defined)  of more than the
Profit Limit and, if exercise of the LaSalle Option  otherwise  would exceed the
Profit Limit,  Trenwick, at its discretion,  may increase the Exercise Price for
that  number  of Option  Shares  set  forth in the  Exercise  Notice so that the
Notional Total Profit shall not exceed the Profit Limit; provided,  that nothing
in this sentence  shall  restrict any exercise of the LaSalle  Option  permitted
hereby on any  subsequent  date at the  Exercise  Price  set forth in  Section 1
hereof.  As used herein,  the term  "Notional  Total Profit" with respect to any
number of Option Shares as to which Trenwick may propose to exercise the LaSalle
Option  shall be the  Total  Profit  determined  as of the date of the  Exercise
Notice  assuming  that the LaSalle  Option were  exercised on such date for such
number of Option Shares and assuming that such Option Shares,  together with all
other shares of LaSalle Common Shares held by Trenwick and its  subsidiaries  as
of such date,  were sold for cash at the  closing  market  price for the LaSalle
Common  Shares  on the  NYSE  Composite  Tape at the  close of  business  on the
preceding trading day (less customary brokerage commissions).




                                       10

<PAGE>

                  12. Certain Repurchases.

                  (a) Trenwick  "Put".  Subject to the  limitations set forth in
Section  11,  upon  delivery  of  written  notice to LaSalle  by  Trenwick  (the
"Repurchase Notice"):

                  (i) at any time during which the LaSalle Option is exercisable
         pursuant  to  Section  2 (the  "Repurchase  Period"),  LaSalle  and its
         successors  in  interest  shall  repurchase  from  Trenwick  all or any
         portion of the LaSalle Option, as specified by Trenwick,  at the Option
         Repurchase Price set forth in Section 12(b)(i); and

                  (ii) at any time  prior to the fifth  anniversary  of the date
         hereof,  LaSalle and its successors in interest shall  repurchase  from
         Trenwick all or any portion of the LaSalle  Common Shares  purchased by
         Trenwick pursuant to the LaSalle Option,  as specified by Trenwick,  at
         the Share Repurchase Price set forth in Section 12(b)(iii).

                  (b)  Certain Definitions  For purposes of this Section 12,
the following definitions shall apply:

                  (i) "Option  Repurchase  Price" shall mean (A) the  difference
         between the Option Repurchase Market/Offer Price (as defined below) for
         the LaSalle Common Shares as of the date of the  applicable  Repurchase
         Notice and the Exercise  Price,  multiplied by (B) the number of shares
         of LaSalle Common Shares purchasable  pursuant to the LaSalle Option or
         the portion thereof covered by the applicable  Repurchase  Notice,  but
         only if the Option  Repurchase  Market/Offer  Price is greater than the
         Exercise Price.

                  (ii) "Option Repurchase  Market/Offer Price" shall mean, as of
         any date,  the higher of (X) the highest  price per share offered as of
         such date pursuant to any tender or exchange  offer or other offer with
         respect to a business combination offer involving LaSalle or any of its
         material  subsidiaries as the target party which was made prior to such
         date and not  terminated  or withdrawn as of such date and (Y) the Fair
         Market  Value (as defined in Section  12(b)(v))  of the LaSalle  Common
         Shares as of such date.

                  (iii) "Share  Repurchase  Price" shall mean the product of (A)
         the sum of (I) the Exercise Price paid by Trenwick per share of LaSalle
         Common Shares  acquired  pursuant to the LaSalle Option and (II) if the
         Share Repurchase  Market/Offer Price (as defined below) is greater than
         the  Exercise  Price,  the  difference  between  the  Share  Repurchase
         Market/Offer  Price  and the  Exercise  Price,  and (B) the  number  of
         LaSalle Common Shares to be repurchased pursuant to this Section 12.




                                       11

<PAGE>

                  (iv) "Share Repurchase  Market/Offer  Price" shall mean, as of
         any date,  the  higher  of (X) the  highest  price  per  share  offered
         pursuant to a tender or exchange  offer or other  business  combination
         offer  involving  LaSalle as the  target  party  during the  Repurchase
         Period prior to the delivery by Trenwick of a notice of repurchase  and
         (Y) the Fair Market Value of the LaSalle Common Shares as of such date.

                  (v) "Fair  Market  Value"  shall  mean,  with  respect  to any
         security, the per share average of the last sale prices on the NYSE (or
         such other national  stock exchange or national  market system as shall
         then be the primary  trading market for such security) for the ten (10)
         trading days immediately preceding the applicable date.

                  (c)  Payment  and  Redelivery  of  LaSalle  Options or LaSalle
Common  Shares.  In the event that  Trenwick  exercises  its  rights  under this
Section 12, LaSalle  shall,  within ten (10) business days  thereafter,  pay the
required  amount to Trenwick in immediately  available  funds and Trenwick shall
surrender  to LaSalle  the LaSalle  Option or the  certificate  or  certificates
evidencing the LaSalle Common Shares purchased by Trenwick pursuant hereto,  and
Trenwick  shall  warrant  that it has sole  beneficial  ownership of the LaSalle
Option or such LaSalle Common Shares and that the LaSalle Option or such LaSalle
Common  Shares  are  then  free  and  clear  of  all  claims,   liens,  charges,
encumbrances and security interests of any nature whatsoever.

                  (d)  Repurchase  Price  Reduced at Trenwick's  Option.  In the
event that payment of the  repurchase  price  specified  in Section  12(a) would
subject the  repurchase  of the  LaSalle  Option or the  LaSalle  Common  Shares
purchased  by  Trenwick  pursuant  to  the  LaSalle  Option  to a  vote  of  the
stockholders of LaSalle pursuant to applicable law, regulations, or requirements
of a national  securities  exchange  or  national  market  system or the LaSalle
Bye-Laws, then Trenwick may, at its election, reduce the repurchase price or the
number of shares covered by the Trenwick  repurchase  request to an amount which
would permit such repurchase without the necessity for such a vote.

                  (e) Repurchase at the Election of LaSalle.

                  (i) Except to the extent that Trenwick  shall have  previously
         exercised its rights under  Section  12(a),  at the written  request of
         LaSalle  during  the  six-month   period   immediately   following  the
         Repurchase Period,  LaSalle may repurchase from Trenwick,  and Trenwick
         shall  sell to  LaSalle,  all (but not less  than  all) of the  LaSalle
         Common Shares acquired by Trenwick  pursuant hereto and with respect to
         which Trenwick has beneficial ownership at the time of such repurchase,
         at a price  equal to the sum of (A) the  greater of (I) one hundred ten
         percent  (110%) of the  Current  Market  Price (as  defined  in Section
         12(e)(iii)) or (II) the sum of (X) the Purchase Price in respect of the
         shares  so  acquired  plus (Y)  Trenwick's  Pre-Tax  Carrying  Cost (as
         defined in Section 12(e)(iii)), multiplied in either case by the number
         of  shares  so  acquired,   and  (B)  the  amount  of  the   documented
         out-of-pocket  expenses  (to the extent not  previously  reimbursed  or
         compensated for pursuant hereto or pursuant to the Business Combination
         Agreement)  incurred  by  Trenwick  in  connection  with  the  Business
         Combination   Agreement  and  this   Agreement  and  the   transactions
         contemplated  thereby  and  hereby,  including  reasonable  accounting,
         investment  banking  and legal  fees  (the  "Section  12(e)  Repurchase
         Consideration");  provided,  that  LaSalle's  rights under this Section
         12(e)  shall  be  suspended   (with  any  such  rights  being  extended
         accordingly)  during any period when the  exercise of such rights would
         subject  Trenwick to liability or disgorgement  of profits  pursuant to
         Section 16(b) of the Exchange Act.



                                       12

<PAGE>


                  (ii) If LaSalle exercises its rights under this Section 12(e),
         LaSalle  shall,  within ten (10)  business  days pay the Section  12(e)
         Repurchase  Consideration  in immediately  available funds and Trenwick
         shall surrender to LaSalle  certificates  evidencing the LaSalle Common
         Shares  purchased  hereunder  with respect to which  Trenwick  then has
         beneficial  ownership,  and  Trenwick  shall  warrant  that it has sole
         beneficial  ownership of such LaSalle  Common  Shares and that all such
         shares  are  then  free  and  clear  of  all  claims,  liens,  charges,
         encumbrances and security interests of any nature whatsoever.

                  (iii) As used in Section 12(e)(i),  (A) "Current Market Price"
         shall  mean the  average  of the last sale  prices per share of LaSalle
         Common  Shares on the NYSE for the ten (10)  trading  days  immediately
         preceding the date of LaSalle's request for repurchase pursuant to this
         Section  12(e) and (B)  "Pre-Tax  Carrying  Cost"  shall mean an amount
         equal to the interest on the aggregate  purchase price paid by Trenwick
         for the LaSalle Common Shares purchased  pursuant to the LaSalle Option
         from the date of  purchase  to the  date of  repurchase  at the rate of
         interest  announced by  Citibank,  N.A. at its prime or base lending or
         reference rate during such period,  less any dividends  received on the
         shares so purchased,  divided by the number of shares of LaSalle Common
         Shares so purchased.

                  13.   Binding   Effect;   No   Assignment;   No  Third   Party
Beneficiaries.  This Agreement shall be binding upon and inure to the benefit of
the  parties  hereto and their  respective  successors  and  permitted  assigns.
Neither this Agreement nor the rights or the  obligations of either party hereto
are  assignable,  except by operation of law, or with the written consent of the
other  party (it being  agreed  that all  transactions  contemplated  by Section
2.1(b) and (c) of the Business  Combination  Agreement  shall not be  considered
assignments  in  violation  of  this  Section  13).  Nothing  contained  in this
Agreement,  express or implied, is intended to confer upon any person other than
the parties hereto and their respective permitted assigns any rights or remedies
of any nature whatsoever by reason of this Agreement. Any Restricted Shares sold
by a  party  in  compliance  with  the  provisions  of  Section  8  shall,  upon
consummation of such sale, be free of the  restrictions  imposed with respect to
such shares by this Agreement,  unless and until such party shall  repurchase or
otherwise become the beneficial owner of such shares, and any transferee of such
shares shall not be entitled to the registration rights of such party.



                                       13

<PAGE>


                  14. Specific Performance. The parties recognize and agree that
if for any reason any of the  provisions of this  Agreement are not performed in
accordance  with their specific terms or are otherwise  breached,  immediate and
irreparable  harm or injury would be caused for which money damages would not be
an adequate  remedy.  Accordingly,  each party agrees that, in addition to other
remedies,  the other party shall be entitled to an  injunction  restraining  any
violation or threatened  violation of the provisions of this  Agreement.  In the
event that any action  should be brought in equity to enforce the  provisions of
the  Agreement,  neither  party will allege,  and each party  hereby  waives the
defense, that there is adequate remedy at law.

                  15. Entire Agreement. This Agreement, the Business Combination
Agreement (including any exhibits and schedules thereto) and the Confidentiality
Agreement  constitute  the  entire  agreement,  and  supersede  all other  prior
agreements and  understandings,  both written and oral, between the parties with
respect to the subject matter of this Agreement.

                  16.  Further  Assurances.  Each party will execute and deliver
all such further  documents and  instruments and take all such further action as
may be necessary in order to consummate the transactions contemplated hereby.

                  17.  Validity.  The  invalidity  or  unenforceability  of  any
provision of this Agreement shall not affect the validity or  enforceability  of
the other  provisions  of this  Agreement,  which shall remain in full force and
effect. In the event any court or other competent authority holds any provisions
of this Agreement to be null,  void or  unenforceable,  the parties hereto shall
negotiate  in good faith the  execution  and  delivery of an  amendment  to this
Agreement  in  order,  as nearly  as  possible,  to  effectuate,  to the  extent
permitted  by law,  the  intent  of the  parties  hereto  with  respect  to such
provision and the economic effects thereof.  If for any reason any such court or
regulatory  agency determines that Trenwick is not permitted to acquire the full
number of shares of LaSalle  Common Shares  provided in Section 1 hereof (as the
same may be adjusted),  it is the express intention of LaSalle to allow Trenwick
to acquire  such  lesser  number of shares as may be  permissible,  without  any
amendment or modification  hereof.  Each party agrees that,  should any court or
other competent authority hold any provision of this Agreement or part hereof to
be  null,  void  or  unenforceable,  or  order  any  party  to take  any  action
inconsistent  herewith,  or not take any action required herein, the other party
shall not be entitled to specific  performance  of such provision or part hereof
or to any other remedy,  including but not limited to money damages,  for breach
hereof or of any other  provision of this Agreement or part hereof as the result
of such holding or order.

                  18. Notices. All notices,  requests, claims, demands and other
communications  under this  Agreement  shall be in  writing  and shall be deemed
given if (i) delivered,  personally,  or (ii) sent by overnight  courier service
(providing proof of delivery), or (iii) telecopied (which is confirmed), or (iv)
five (5) days after being mailed by registered or certified mail (return receipt
requested) to the parties at the  following  addresses (or at such other address
for a party as shall be specified by like notice):



                                       14

<PAGE>


                  If to Trenwick:

                           Alan L. Hunte
                           Vice President and
                              Chief Financial Officer
                           Trenwick Group Inc.
                           One Canterbury Green
                           Stamford, CT 06901
                           Fax: (203) 353-5550

                  with a copy to:

                           Baker & McKenzie
                           805 Third Avenue
                           New York, New York 10022
                           Attention: James R. Cameron
                           Fax: (212) 891-3835

                  If to LaSalle, to:

                           LaSalle Re Holdings Limited
                              Continental Building
                           25 Church Street
                           Hamilton HM 12
                           Bermuda
                           Fax: (441) 292-1501

                  with a copy to:

                           Mayer, Brown & Platt
                           190 S. LaSalle Street
                           Chicago, Illinois 60603
                           Attention: Richard W. Shepro
                           Fax: (312) 701-7711

                  19.  Governing Law;  Choice of Forum.  This Agreement shall be
governed by, and construed in accordance with, the laws of the State of Delaware
without regard to the conflicts of law principles  thereof.  Each of the parties
hereto (a) consents to submit itself to the personal jurisdiction of any federal
court located in the State of Delaware or any Delaware  state court in the event
any dispute arises out of this Agreement or any of the transactions contemplated
by this  Agreement,  (b) agrees  that it will not attempt to deny or defeat such
personal  jurisdiction  by motion or other request for leave from any such court
and (c) agrees that it will not bring any action  relating to this  Agreement or
any of the transactions contemplated by this Agreement in any court other than a
federal court sitting in the state of Delaware or a Delaware state court.



                                       15

<PAGE>


                  20. Interpretation. When a reference is made in this Agreement
to a Section,  such  reference  shall be to a Section of this  Agreement  unless
otherwise indicated. Whenever the words "include", "includes" or "including" are
used in this  Agreement,  they  shall be  deemed  to be  followed  by the  words
"without   limitation."  The  descriptive   headings  herein  are  inserted  for
convenience  of  reference  only and are not intended to be part of or to affect
the meaning or interpretation of this Agreement.

                  21.  Counterparts.  This  Agreement  may be executed in one or
more counterparts,  each of which shall be deemed to be an original, but both of
which, taken together, shall constitute one and the same instrument.

                  22. Expenses. Except as otherwise expressly provided herein or
in the  Business  Combination  Agreement,  all costs and  expenses  incurred  in
connection with the transactions contemplated by this Agreement shall be paid by
the party incurring such expenses.

                  23. Amendment. This Agreement may not be amended, except by an
instrument in writing signed on behalf of each of the parties.

                  24. Waiver.  Any agreement on the part of a party to waive any
provision  of this  Agreement,  or to extend the time for  performance,  will be
valid only if set forth in an  instrument  in  writing  signed on behalf of such
party.  The failure of any party to this  Agreement  to assert any of its rights
under this Agreement or otherwise will not constitute a waiver of such rights.

                  25. Loss or  Mutilation.  Upon  receipt by LaSalle of evidence
reasonably  satisfactory to it of the loss, theft,  destruction or mutilation of
this  Agreement,  and (in the case of loss,  theft or destruction) of reasonably
satisfactory  indemnification,  and  upon  surrender  and  cancellation  of this
Agreement,  if  mutilated,  LaSalle  will  execute and deliver to Trenwick a new
Agreement of like tenor and date. Any such new Agreement  executed and delivered
will  constitute  an additional  contractual  obligation on the part of LaSalle,
whether or not the Agreement so lost, stolen,  destroyed,  or mutilated shall at
any time be enforceable by anyone.

                  26. Extension of Time Periods.  The time periods for exercises
of certain rights  hereunder shall be extended (but in no event by more than six
(6) months):  (a) to the extent necessary to obtain all  governmental  approvals
for the exercise of such rights, and for the expiration of all statutory waiting
periods;  and (b) to the extent necessary to avoid any liability or disgorgement
of profits under Section 16(b) of the Exchange Act by reason of such exercise.




                                       16

<PAGE>

                  27.  Further  Assurance.  Each  party  agrees to  execute  and
deliver all such further  documents  and  instruments  and take all such further
action as may be necessary in order to consummate the transactions  contemplated
hereby.


















                                       17

<PAGE>


                  IN WITNESS  WHEREOF,  the  parties  hereto  have  caused  this
Agreement to be executed by their respective duly authorized  officers as of the
date first above written.

                                      TRENWICK GROUP INC.


                                      By: /s/ James F. Billett, Jr.
                                           -----------------------------
                                           Name:  James F. Billett, Jr.
                                           Title: Chairman, President and
                                                  Chief Executive Officer


                                      LASALLE RE HOLDINGS LIMITED


                                      By: /s/  Guy D. Hengesbaugh
                                          -------------------------------
                                          Name:  Guy D. Hengesbaugh
                                          Title: President and Chief Executive
                                                 Officer







                                       18



                             SHAREHOLDERS AGREEMENT

         SHAREHOLDERS  AGREEMENT  (this  "Agreement")  dated as of December  19,
1999, by and among Trenwick Group Inc., a Delaware corporation ("Trenwick"), and
the other parties  signatory  hereto (each, a  "Shareholder"  and together,  the
"Shareholders").

                                    RECITALS

         WHEREAS,   simultaneously   herewith   Trenwick  is  entering  into  an
Agreement,  Scheme of  Arrangement,  Plan of Merger and Plan of  Reorganization,
dated as of December  19,  1999,  by and among  LaSalle Re  Holdings,  a company
organized under the laws of Bermuda ("LaSalle Holdings"),  LaSalle Re Limited, a
company  organized  under the laws of Bermuda  ("LaSalle Re"),  Trenwick,  Gowin
Holdings  International  Limited,  a company organized under the laws of Bermuda
("New Holdings") and Trenwick Group (Delaware) Inc., a Delaware corporation (the
"Business Combination Agreement");

         WHEREAS, the Business Combination  Agreement provides that Trenwick and
LaSalle  Holdings  will be entering  into a series of  transactions  pursuant to
which (i) New Holdings  will become the holding  company of such  companies  and
(ii)  shareholders  of  LaSalle  Holdings  and  LaSalle Re and  stockholders  of
Trenwick  will  become  shareholders  of New  Holdings  as  set  forth  in  such
agreement;

         WHEREAS,  each  Shareholder  owns that number of (i) LaSalle  Holdings'
common shares, par value $1.00 per share (the "Common Shares"), and (ii) LaSalle
Re's exchangeable  non-voting shares (the "Non-Voting Shares" and, together with
the Common  Shares,  the  "Shares",  which term shall  include  Shares which are
acquired or may be acquired  upon the exercise of any and all options to acquire
Common Shares and Non-Voting Shares  ("Options"),  whether such Options exist on
the date  hereof or  otherwise)  set forth  next to such  Shareholder's  name on
Exhibit A hereto; and

         WHEREAS,  as a condition to its  willingness to enter into the Business
Combination  Agreement,  Trenwick has required that each Shareholder  agree, and
each  Shareholder  has agreed,  among other things,  to execute and deliver this
Agreement  with respect to the Shares owned (whether by conversion or otherwise)
by such Shareholder, on the terms and conditions provided for herein.

         NOW,  THEREFORE,  in  consideration  of the  foregoing  and the  mutual
representations,  warranties,  covenants and agreements  herein  contained,  the
parties hereto agree as follows:

         1.  Voting  Agreement.  At any meeting of the  shareholders  of LaSalle
Holdings  or  LaSalle Re called to vote upon the  Scheme of  Arrangement  or the
Business  Combination  Agreement or at any  adjournment  thereof or in any other
circumstances  upon which a vote,  consent or other approval of  shareholders of
LaSalle Holdings or LaSalle Re with respect to any of the other matters referred
to below is  sought,  each  Shareholder  hereby  agrees  to vote (or cause to be
voted) the Shares held of record or beneficially  by such  Shareholder as of the
applicable record date (i) in favor of the Scheme of Arrangement,  the execution
and  delivery by LaSalle  Holdings  and LaSalle Re of the  Business  Combination
Agreement  and the approval of the terms  thereof and each of the other  actions
contemplated  by the Business  Combination  Agreement,  this  Agreement  and any
actions required in furtherance  hereof and thereof;  (ii) against any action or
agreement  that would,  to its  knowledge,  result in a breach of any  covenant,
representation  or  warranty or any other  obligation  or  agreement  of LaSalle
Holdings  or  LaSalle  Re  under  the  Business  Combination  Agreement  or this
Agreement;  and (iii) against the following  actions  (other than the Scheme and
the transactions  contemplated by the Business Combination  Agreement):  (1) any
extraordinary   corporate   transaction,   such  as  a  merger,   consolidation,
amalgamation or other business combination  involving LaSalle Holdings or any of
its subsidiaries (including,  without limitation, LaSalle Re); (2) a sale, lease


                                       1

<PAGE>

or  transfer  of a material  amount of assets of LaSalle  Holdings or any of its
subsidiaries(including,  without  limitation,  LaSalle Re) or a  reorganization,
recapitalization,  dissolution or liquidation of LaSalle  Holdings or any of its
subsidiaries (including,  without limitation, LaSalle Re); (3) (a) any change in
the majority of the Board of  Directors  of LaSalle  Holdings or LaSalle Re; (b)
any material change in the present capitalization of LaSalle Holdings or LaSalle
Re or any material  amendment of LaSalle Holdings' or LaSalle Re's Memorandum of
Association and Bye-laws;  (c) any other material change in LaSalle Holdings' or
LaSalle Re's corporate  structure or business;  or (d) any other action which is
intended,  or could reasonably be expected,  to impede,  interfere with,  delay,
postpone, discourage or materially adversely affect the Scheme of Arrangement or
the  transactions  contemplated  by the Business  Combination  Agreement or this
Agreement or the contemplated  economic  benefits of any of the foregoing.  Each
Shareholder  hereby revokes any proxy  previously  granted by it with respect to
the Shares.  Each Shareholder hereby agrees,  while this Agreement is in effect,
and except as  contemplated  hereby,  not to take any action that would make any
representation  or  warranty  of such  Shareholder  contained  herein  untrue or
incorrect or have the effect of preventing or disabling  such  Shareholder  from
performing his or its obligations under this Agreement;  provided, however, that
nothing in this Agreement  shall be deemed to prohibit or restrict in any manner
any Shareholder from selling, transferring, or otherwise disposing of any Shares
or Options to any person.  The provisions of this Section 1 shall  terminate and
no longer bind the  Shareholders  at such time as the LaSalle  Holdings Board of
Directors  either (A) withdraws or modifies its approval and  recommendation  of
the Business Combination Agreement pursuant to clause (x) of the second sentence
of  Section  5.3(b)(ii)  thereof  or (B)  terminates  the  Business  Combination
Agreement  pursuant to clause (y) of the second  sentence of Section  5.3(b)(ii)
thereof.

         2.   Representations  and  Warranties  of  Trenwick.   Trenwick  hereby
represents and warrants to each  Shareholder  that the execution and delivery of
this Agreement and the consummation of the transactions contemplated hereby have
been duly and validly  authorized  by the Board of  Directors of Trenwick and no
other  corporate  proceedings on the part of Trenwick are necessary to authorize
this  Agreement or to consummate  the  transactions  contemplated  hereby.  This
Agreement  has been duly and validly  executed  and  delivered  by Trenwick  and
constitutes  a valid and binding  agreement  of  Trenwick,  enforceable  against
Trenwick in accordance with its terms,  except that such  enforceability (i) may
be limited by bankruptcy, insolvency, moratorium or other similar laws affecting
or relating to enforcement of creditors' rights generally and (ii) is subject to
general principles of equity.

         3. Representations and Warranties of the Shareholders. Each Shareholder
hereby  represents  and  warrants,  severally  and not  jointly,  to Trenwick as
follows:

                  (a) Ownership of Shares and Options.  Such Shareholder,  as of
         the date  hereof,  (i) is the owner of the number of Shares and Options
         set forth next to such  Shareholder's name on Exhibit A hereto and (ii)
         has the sole power to vote (or to give any consent that may be required
         in respect of such Shares and  Options)  and dispose of such Shares and
         Options.

                  (b) Power;  Binding Agreement.  Such Shareholder has the legal
         capacity,  power and  authority  to enter into and  perform  all of its
         obligations   under  this  Agreement.   The  execution,   delivery  and
         performance of this Agreement by such  Shareholder will not violate any
         other agreement to which such Shareholder is a party including, without
         limitation,  any voting  agreement,  shareholders  agreement  or voting
         trust.  This Agreement has been duly and validly  authorized,  executed
         and delivered by such  Shareholder  and constitutes a valid and binding
         agreement of such Shareholder,  enforceable against such Shareholder in
         accordance with its terms,  except that such  enforceability (i) may be
         limited by  bankruptcy,  insolvency,  moratorium  or other similar laws
         affecting or relating to enforcement of creditors' rights generally and
         (ii) is subject to general principles of equity.


                                       2

<PAGE>

                  (c) No Conflicts.  (A) No filing by such Shareholder with, and
         no permit, authorization, consent or approval of, any state, federal or
         foreign public body or authority is necessary for the execution of this
         Agreement by such  Shareholder and the consummation by such Shareholder
         of the transactions  contemplated  hereby and (B) neither the execution
         and delivery of this Agreement by such Shareholder nor the consummation
         by  such  Shareholder  of  the  transactions  contemplated  hereby  nor
         compliance by such Shareholder with any of the provisions  hereof shall
         (1)  conflict  with or result in any  breach  of any  provision  of the
         certificate of incorporation,  by-laws, trust or charitable instruments
         (or similar  documents) of such Shareholder,  (2) result in a violation
         or breach of, or constitute (with or without notice or lapse of time or
         both) a default (or give rise to any third party right of  termination,
         cancellation,  material  modification or acceleration) under any of the
         terms, conditions or provisions of any note, bond, mortgage, indenture,
         license, contract, agreement or other instrument or obligation to which
         such  Shareholder  is a party or by which he or it or any of his or its
         properties  or assets  may be bound or (3)  violate  any  order,  writ,
         injunction,  decree,  statute,  rule or  regulation  applicable to such
         Shareholder  or any of his or its  properties or assets,  except in the
         case of (A) or (B) for violations, breaches or defaults which would not
         in the  aggregate  materially  adversely  affect  the  ability  of such
         Shareholder to perform its obligations hereunder.

         4.  Adjustments  to  Prevent  Dilution,  Etc.  In the  event of a stock
dividend or  distribution,  or any change in LaSalle  Holdings'  or LaSalle Re's
capital  shares by reason of any  share  dividend,  split-up,  reclassification,
recapitalization, combination or the exchange of shares, the term "Shares" shall
be deemed to refer to and include the Shares as well as all such stock dividends
and  distributions  and any  shares  into  which or for  which any or all of the
Shares may be changed or exchanged.

         5.       Miscellaneous.

                  (a)  Entire  Agreement.  This  Agreement  contains  the entire
understanding  of the parties with respect to the subject  matter hereof and may
not be amended except by a writing signed by the parties. Except as specifically
provided  herein,  this  Agreement  is not  assignable  by  any of the  parties,
provided that none of the  transactions  described in Sections 2.1(b) and 2.1(c)
of the Business  Combination  Agreement  shall be  considered  an  assignment by
Trenwick.  This Agreement shall be binding upon the respective successors of the
parties  and  upon   transferees  of  the  Shares  who  are  Affiliates  of  the
transferring Shareholder.

                  (b) Notices. All notices,  requests, claims, demands and other
communications  hereunder  shall be in writing  and shall be given (and shall be
deemed to have been duly received if so given) by hand delivery, telegram, telex
or telecopy,  or by mail (registered or certified mail, postage prepaid,  return
receipt requested) or by any courier service, such as Federal Express, providing
proof of  delivery.  All  communications  hereunder  shall be  delivered  to the
respective parties at the following addresses:

         If to a Shareholder,  to the address of such  Shareholder  indicated on
Exhibit A hereto.

         If to Trenwick:

                      Trenwick Group Inc.
                      One Canterbury Green
                      Stamford, Connecticut 06901
                      Attention: Steve Bensinger and
                                     John Del Col, Esq.
                      Facsimile No.: (203) 353-5544



                                       3

<PAGE>

                      with a copy to:

                      Baker & McKenzie
                      805 Third Avenue
                      New York, New York 10022
                      Attention: James R. Cameron, Esq.
                      Facsimile No.: (212) 891-3835


         If to New Holdings:

                      Gowin Holdings International Limited
                      c/o Appleby Spurling & Kempe
                      Cedar House
                      41 Cedar Avenue
                      P.O. Box Hm 1179
                      Hamilton Bermuda HMEX
                      Attention: Warren Cabral
                      Facsimile No: (441) 292-8666


                      With a copy to:

                      Baker & McKenzie
                      805 Third Avenue
                      New York, New York 10022
                      Attention: James R. Cameron, Esq.
                      Facsimile No.: (212) 891-3835


or to such  other  address  as the  person  to whom  notice  is  given  may have
previously furnished to the others in writing in the manner set forth above.

         (c) Notification by Shareholder. Each Shareholder shall notify Trenwick
from time to time, upon request,  of the number of Shares  beneficially owned by
such Shareholder.

         (d) Governing Law. This Agreement  shall be governed in all respects by
the laws of the State of  Delaware  without  regard  to any laws or  regulations
relating  to  choice of laws  (whether  of the  State of  Delaware  or any other
jurisdiction)  that would cause the application of the laws of any  jurisdiction
other than the State of Delaware.

         (e) Cooperation. Subject to the terms and conditions of this Agreement,
each of the parties  hereby  agrees to use its best efforts to take, or cause to
be taken,  all  action  and to do, or cause to be done,  all  things  necessary,
proper or advisable under  applicable  laws, rules and regulations to consummate
and make effective the actions  contemplated by this  Agreement.  In case at any
time after the  execution  of this  Agreement,  further  action is  necessary or
desirable to carry out the purposes of this  Agreement,  the proper officers and
directors  of each of the parties  shall take all such  necessary  or  desirable
action.

         (f) Specific  Performance.  Each of the parties  hereto  recognizes and
acknowledges  that a breach by it of any  covenants or  agreements  contained in
this Agreement will cause the other party to sustain  damages for which it would
not have an adequate remedy at law for money damages, and therefore, each of the
parties  hereto agrees that in the event of any such breach the aggrieved  party
shall be entitled to the remedy of specific  performance  of such  covenants and
agreements and injunctive  and other  equitable  relief in addition to any other
remedy to which it may be entitled, at law or in equity.



                                       4

<PAGE>


         (g)  Counterparts.  This  Agreement  may be  executed  in  one or  more
counterparts,  each of which shall be deemed to be an original, but all of which
shall constitute one and the same Agreement.

         (h)  Definitions.  Capitalized  terms used but not defined herein shall
have the meanings set forth in the Business Combination Agreement.

         (i)  Descriptive  Headings.  The  descriptive  headings used herein are
inserted for convenience of reference only and are not intended to be part of or
to affect the meaning or interpretation of this Agreement.

         (j) Severability.  Whenever possible,  each provision or portion of any
provision  of  this  Agreement  will be  interpreted  in  such  manner  as to be
effective and valid under  applicable law but if any provision or portion of any
provision of this Agreement is held to be invalid,  illegal or  unenforceable in
any  respect  under  any  applicable  law  or  rule  in any  jurisdiction,  such
invalidity,  illegality or unenforceability  will not affect any other provision
or portion of any provision in such  jurisdiction,  and this  Agreement  will be
reformed,  construed  and  enforced  in such  jurisdiction  as if such  invalid,
illegal or  unenforceable  provision or portion of any  provision had never been
contained herein.

         (k) Termination.  Unless earlier  terminated as provided  herein,  this
Agreement  shall  terminate,  without  further  liability or  obligation  of the
parties  hereto,  including  liability for damages,  upon the earlier of (i) the
180th  calendar  day  following  the  termination  of the  Business  Combination
Agreement in accordance  with its terms and (ii)  consummation  of the Scheme of
Arrangement.









                                       5

<PAGE>



         IN WITNESS WHEREOF, this Agreement has been executed by or on behalf of
each of the parties hereto, all as of the date first above written.


                               TRENWICK GROUP INC.


                               By:/s/ James F. Billett, Jr.
                                  ----------------------------------
                               Name:  James F. Billett, Jr.
                               Title: Chairman, President and Chief
                                      Executive Officer


                               SHAREHOLDERS:

                               COMBINED INSURANCE COMPANY OF AMERICA

                               By: /s/ Michael A. Conway
                                   ---------------------------------
                               Name:  Michael A. Conway
                               Title: Senior Vice President


                               VIRGINIA SURETY COMPANY, INC.

                               By: /s/ Michael A. Conway
                                   ---------------------------------
                               Name:  Michael A. Conway
                               Title: Vice President


                               AON RISK CONSULTANTS (BERMUDA) LTD.

                               By: /s/ Michael A. Conway
                                   ---------------------------------
                               Name:  Michael A. Conway
                               Title: Authorized Agent


                               CONTINENTAL CASUALTY COMPANY

                               By:  /s/ Robert V. Deutsch
                                   ---------------------------------
                               Name:  Robert V. Deutsch
                               Title: Senior Vice President and Chief
                                      Financial Officer


                               CNA (BERMUDA) SERVICES LIMITED

                               By:  /s/ Robert V. Deutsch
                                   ---------------------------------
                               Name:  Robert V. Deutsch
                               Title: Authorized Agent



                                       6

<PAGE>


                                    EXHIBIT A




                                                      NUMBER OF
                                    NUMBER OF         EXCHANGEABLE
                                    COMMON SHARES     NON-VOTING       OPTIONS
SHAREHOLDER NAME                    OF LASALLE        SHARES OF        AND/OR
AND ADDRESS                         HOLDINGS          LASALLE RE       WARRANTS
- --------------------
Combined Insurance Company
of America                             322,715        1,221,750              0

Virginia Surety Company, Inc.          322,715        1,221,750              0

Aon Risk Consultants (Bermuda) Ltd.    555,244                0              0

Continental Casualty Company         1,425,354        1,963,896              0

CNA (Bermuda) Services Limited               0          318,150              0




          TRENWICK GROUP INC. AND LASALLE RE HOLDINGS LIMITED TO MERGE

      Stamford, Connecticut and Hamilton, Bermuda, December 19, 1999 . . .

Trenwick Group Inc.  ("Trenwick")  (NYSE:  TWK) and LaSalle Re Holdings  Limited
("LaSalle Re") (NYSE:  LSH)  announced  today that they have signed a definitive
agreement  for  Trenwick  and  LaSalle Re to merge,  with  shareholders  of both
companies receiving shares in a new Bermuda holding company to be named Trenwick
Group Ltd. James F. Billett, Jr. will continue as Chairman,  President and Chief
Executive  Officer of the new Trenwick,  and Guy D.  Hengesbaugh,  President and
Chief  Executive  Officer of LaSalle Re, will continue in those roles at LaSalle
Re, which will become a subsidiary of the new  Trenwick.  The Board of Directors
of the new Trenwick will consist of the twelve current Trenwick  directors,  and
four directors from the present LaSalle Re Board.

Under the terms of the merger agreement, shareholders of Trenwick and LaSalle Re
will each receive  shares in the newly formed  Trenwick on a one-for-one  basis.
The transaction is expected to be tax-free to shareholders of both companies.

James F.  Billett,  Jr.,  Trenwick's  Chairman,  President  and Chief  Executive
Officer,  said, "This strategic  merger creates a significant new  Bermuda-based
global  insurance  and  reinsurance  underwriting   organization  with  a  total
capitalization of over $1.2 billion. This transaction,  which is the most recent
step in Trenwick's  strategic  evolution,  is exciting for us since it creates a
company  with  larger  scale  and  stronger   competitive   capabilities   in  a
consolidating global  insurance/reinsurance  market, adds higher margin business
to Trenwick's  existing mix,  creates a better  platform to enhance  shareholder
returns,  and expands the management depth of Trenwick by adding Guy Hengesbaugh
and his team. The combined  enterprise  will have a strong presence in the three
most significant  insurance markets in the world: the United States,  London and
Bermuda."

"This merger represents a tremendous step forward in offering LaSalle Re clients
top-notch financial security while giving LaSalle Re shareholders the
opportunity to realize greater value," said Guy D. Hengesbaugh, President and
Chief Executive Officer of LaSalle Re.

On a combined basis, the new Trenwick would have had assets in excess of
$3.5 billion, shareholders' equity of over $950 million and total capitalization
of  approximately  $1.2  billion  as of  September  30,  1999.  Based on current
projections,  combined 1999 gross  written  premiums for all of the new Trenwick
companies are expected to approach $1.0 billion.

The companies  believe that the transaction  provides a cost-effective  means of
augmenting capital and adding structural  platforms for further  expansion.  The
addition of LaSalle Re's high margin specialist property catastrophe reinsurance
business continues Trenwick's strategy of entering new markets and product lines
that began with  Trenwick's  acquisition  of  Trenwick  International  (formerly
Sorema U.K.),  completed in February 1998, and Trenwick's recent  acquisition of
Chartwell Re Corporation,  completed in October 1999. The addition of LaSalle Re
will provide the new Trenwick with a significant level of financial  flexibility
and the  opportunity to develop new business  products.  Trenwick and LaSalle Re
expect that consolidating the two companies will generate significant  financial
benefits and will be accretive to Trenwick's and LaSalle Re's shareholders.

CNA  Financial  Corporation  and  Aon  Corporation,   founding  and  significant
shareholders of LaSalle Re, have each agreed to vote in favor of the merger.

Bernard L.  Hengesbaugh,  Chairman and Chief Executive Officer of CNA Insurance,
stated, "CNA wholeheartedly endorses the transaction, which is highly beneficial
for LaSalle Re's  shareholders and clients.  This transaction  further evidences
CNA's commitment to providing creative solutions, which are best met in a global
platform."


                                       1

<PAGE>

Michael D.  O'Halleran,  President and Chief Operating  Officer of Aon,  stated,
"Aon is very pleased to support the merger of LaSalle Re with Trenwick.  We have
worked with Trenwick and its CEO, Jim Billett, for many years, and recognize the
outstanding opportunity this transaction provides for the combined companies and
their shareholders and clients."

The  transaction  is  subject  to  the  approval  of the  respective  companies'
shareholders,  regulatory approvals and other customary closing conditions.  The
transaction is expected to be completed early in the second quarter of 2000. The
merger  agreement  provides for the payment of  termination  fees under  certain
circumstances,  and Trenwick  and LaSalle Re have also  entered  into  customary
"cross" stock option agreements.

Trenwick  Group  Inc.  is  a  holding  company  with  four  principal  operating
subsidiaries: Trenwick America Re, which provides treaty reinsurance to insurers
of property and casualty  risks in the United  States;  Trenwick  International,
which  underwrites  treaty  and  facultative  reinsurance  as well as  specialty
insurance on a worldwide basis;  Chartwell  Managing Agents Limited,  Trenwick's
managing  agency  at  Lloyd's;   and  Canterbury  Financial  Group  Inc.,  which
underwrites  U.S.  property and casualty  insurance  through  specialty  program
administrators.   All  of  Trenwick's   principal   insurance  and   reinsurance
subsidiaries  are rated A  (Excellent)  by A.M.  Best Company and are assigned a
financial strength rating of A+ by Standard & Poor's.

LaSalle Re is a property and casualty  reinsurer  writing  worldwide  specialist
products  with an  emphasis  on  catastrophe  coverage.  LaSalle  Re is  rated A
(Excellent)  by A.M. Best Company and currently  holds an A- financial  strength
rating from Standard & Poor's.

Donaldson, Lufkin & Jenrette Securities Corporation acted as financial advisor
to Trenwick; Lazard Freres & Co. LLC, Salomon Smith Barney Inc. and Aon Capital
Markets, Inc. acted as financial advisors to LaSalle Re.

                                     * * *
This press release contains forward looking statements of management's beliefs,
estimates,  projections and assumptions for the financial condition,  results of
operations,  business and  prospects of Trenwick  after the  transaction.  These
forward looking statements  involve certain risks and  uncertainties,  including
those  detailed  from time to time in  Trenwick's  and LaSalle  Re's reports and
filings with the Securities and Exchange Commission. Additional factors that may
cause  actual  results  to differ  materially  from those  contemplated  by such
forward looking  statements  include,  among others,  that the completion of the
transaction  may be  delayed  or not  occur,  that  difficulties  related to the
integration  of the  businesses  of Trenwick  and  LaSalle Re are  greater  than
expected or that expectations for growth may not be realizable.

December 19, 1999


Contacts:                  Alan L. Hunte, Executive Vice President, and
                           Chief Financial Officer
                           Trenwick Group Inc. (NYSE: TWK)
                           (203) 353-5500

                           Diane Newman, Investor Relations Manager
                           LaSalle Re Holdings Limited (NYSE: LSH )
                           (441) 292-3339



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