Transaction in Own Shares

National Grid PLC
15 February 2007




National Grid plc announces that on 14 February 2007 it purchased for
cancellation 450,000 of its ordinary shares at a price of 790.0105 pence per
share.

Following the purchase and upon the cancellation of these shares, the number of
ordinary shares with voting rights in issue will be 2,712,388,732.
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