Transaction in Own Shares

National Grid PLC
18 December 2007


National Grid plc - Transaction in Own Shares


18 December 2007


National Grid plc announces that on 17 December 2007 it purchased 730,000 of its
ordinary shares at a price of 839.7008 pence per share from Morgan Stanley
Securities Limited. The purchased shares will be held as Treasury shares.

Following the purchase of these shares, the number of ordinary shares with
voting rights in issue (excluding Treasury shares) will be 2,552,339,842 and the
number of ordinary shares in Treasury will be 29,573,674.


End



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