Transaction in Own Shares

National Grid PLC
18 September 2007

National Grid plc - Transaction in Own Shares

18 September 2007

National Grid plc announces that on 17 September 2007 it purchased for
cancellation 800,550 of its ordinary shares at a price of 744.5136 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
2,601,075,170 and the number of ordinary shares in Treasury will be 13,601,486.


End



                      This information is provided by RNS
            The company news service from the London Stock Exchange