Transaction in Own Shares

National Grid PLC
02 March 2007


National Grid plc announces that on 01 March 2007 it purchased for cancellation
700,000 of its ordinary shares at a price of 756.5400 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 2,707,082,769.
--------------------------------------------------------------------------------


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