Transaction in Own Shares

National Grid PLC
26 February 2007

National Grid plc announces that on 23 February 2007 it purchased for
cancellation 100,000 of its ordinary shares at a price of 779.8817 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 2,709,213,495.
--------------------------------------------------------------------------------


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