SIP Operation

National Grid PLC
08 August 2007


National Grid plc (NG)


8th August 2007


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 33,156 NG ordinary shares under
the scheme was confirmed by the Trustee late yesterday, the shares having been
purchased in the market on 7 August, at a price of 718.5 pence per share, on
behalf of some 2,600 participants.

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


Director                       Shares purchased in SIP
Mark Fairbairn                 18 Ordinary Shares
Steven Holliday                18 Ordinary Shares



The Directors total interests after these events are:



Director                             Resulting total interest
Mark Fairbairn                       318,618 Ordinary Shares

                                     B Shares- 6,132- unchanged
Steven Holliday                      717,005 Ordinary Shares

                                     Nil- B shares - unchanged



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



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