Transaction in Own Shares

National Grid PLC
24 September 2007

National Grid plc - Transaction in Own Shares

24 September 2007

National Grid plc announces that on 21 September 2007 it purchased for
cancellation 1,204,747 of its ordinary shares at a price of 763.8058 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
2,597,589,236 and the number of ordinary shares in Treasury will be 13,601,486.




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