Transaction in Own Shares

National Grid PLC
16 February 2007

National Grid plc announces that on 15 February 2007 it purchased for
cancellation 500,000 of its ordinary shares at a price of 793.2716 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 2,711,888,732.


--------------------------------------------------------------------------------




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