SIP Operation

National Grid PLC
08 January 2008

National Grid plc ('NG')

8th January 2008

Notification of Directors' Interests

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


NG SHARE INCENTIVE PLAN (the 'SIP')

Under the SIP scheme, operated through Towers Perrin Share Plan Services Limited
as Trustee, employees may acquire NG ordinary shares by regular monthly
contributions.  The current monthly purchase of 26,416 NG ordinary shares under
the scheme was confirmed by the Trustee yesterday, the shares having been
purchased in the market on Monday 7th January, at a price of 851.5 pence per
share, on behalf of some 2,500 participants.

The following Executive Directors of NG are beneficiaries of the shares
purchased on their behalf:

Director                       Shares purchased in SIP
Mark Fairbairn                 15 Ordinary Shares
Steven Holliday                14 Ordinary Shares



The Directors total interests after these events are:

Director                             Resulting total interest
Mark Fairbairn                       357,714 Ordinary Shares
Steven Holliday                      796,894 Ordinary Shares

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

Contact: D C Forward, Assistant Secretary- (0207 004 3226)



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