<PAGE>
FIRST AMENDMENT
TO
AGREEMENT AND PLAN OF MERGER
AND
SCHEME OF ARRANGEMENT
This First Amendment, dated as of December 1, 2000, is made by and among
National Grid Group plc, a public limited company incorporated under the laws of
England and Wales with registration number 2367004 ("PARENT"), Niagara Mohawk
Holdings, Inc., a New York corporation (the "COMPANY"), New National Grid plc, a
public limited company incorporated under the laws of England and Wales with
registration number 4031152 ("NEWCO") and Grid Delaware, Inc., a Delaware
corporation and a wholly owned subsidiary of Newco ("MERGER SUB").
RECITALS
WHEREAS, the parties hereto are parties to the Agreement and Plan of Merger
and Scheme of Arrangement dated September 4, 2000 (the "AGREEMENT"); and
WHEREAS, the parties hereto desire to amend the Agreement as hereinafter set
forth.
NOW, THEREFORE, the parties hereto, intending to be legally bound hereby
agree as follows:
1. Paragraph (a) of Section 2.2 of the Agreement is hereby amended and restated
to read in its entirety as follows:
(a) CONVERSION OF MERGER SUB SHARES. As of the Merger Effective Time, and in
consideration for the Merger Consideration given by Newco, each issued
and outstanding share of common stock, par value $0.10 per share, of
Merger Sub (the "MERGER SUB COMMON STOCK"), will be converted into the
right to receive a number of shares of common stock to be issued at the
Merger Effective Time by the Surviving Entity equal to the number of
shares of common stock, par value $0.01 per share, of the Company (the
"COMPANY COMMON STOCK") divided by the number of issued and outstanding
shares of Merger Sub Common Stock, in each case at the Merger Effective
Time.
2. Except as specifically amended hereby, the Agreement shall remain in full
force and effect.
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IN WITNESS WHEREOF, each party hereto has caused this First Amendment to be
signed by its respective officer thereunto duly authorized as of the date first
written above.
<TABLE>
<S> <C>
NATIONAL GRID GROUP PLC
By: /s/ Richard P. Sergel
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Its: Group Director, North America
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NIAGARA MOHAWK HOLDINGS, INC.
By /s/ William E. Davis
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Its: Chairman of the Board and
Chief Executive Officer
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NEW NATIONAL GRID PLC
By:
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Its:
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GRID DELAWARE, INC.
By: /s/ Richard P. Sergel
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Its: President
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</TABLE>
