SIP operation

National Grid PLC
08 February 2008


National Grid plc ('NG')

8th February 2008

Notification of Directors' Interests

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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 29,806 NG ordinary shares under
the scheme was confirmed by the Trustee yesterday, the shares having been
purchased in the market on Thursday 7th February, at a price of 775.8 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                 16 Ordinary Shares
Steven Holliday                17 Ordinary Shares


The Directors total interests after these events are:

Director                             Resulting total interest

Mark Fairbairn                       358,144 Ordinary Shares
Steven Holliday                      796,911 Ordinary Shares

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



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