Transaction in Own Shares

National Grid PLC
21 November 2006



National Grid plc

21 November 2006

National Grid plc announces that on 20 November 2006 it purchased for
cancellation 500,000 of its ordinary shares at a price of 723.90 pence per share
from Deutsche Bank AG London Branch.

Following the purchase and upon the cancellation of these shares, the number of
ordinary shares in issue will be 2,721,718,957.

CONTACT DETAILS

Investors
David Rees         [phone]           [phone](m)
Richard Smith      [phone]           [phone](m)
James Waite        [phone]           [phone](m)

Media
Clive Hawkins      [phone]           [phone](m)


END




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