Transaction in Own Shares

National Grid PLC
12 September 2007




National Grid plc - Transaction in Own Shares

12 September 2007


National Grid plc announces that on 11 September 2007 it purchased for
cancellation 655,174 of its ordinary shares at a price of 727.7616 pence per
share from Morgan Stanley Securities Limited.

Following the purchase and upon cancellation of these shares, the number of
ordinary shares with voting rights in issue (excluding Treasury shares) will be
2,603,929,416 and the number of ordinary shares in Treasury will be 13,601,486.


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