SIP Operation

National Grid PLC
10 October 2006


National Grid plc (NG)

10 October 2006

(Notifications of Directors' Interests, pursuant to Section 324(2) of the 
Companies Act 1985)

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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 36,417 NG ordinary shares under
the scheme was confirmed by the Trustee today, the shares having been purchased
in the market yesterday, at a price of 678.5 pence per share, on behalf of some
2,700 participants.

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

Director                       Shares purchased in SIP

Steven Holliday                18 Ordinary Shares
Roger Urwin                    18 Ordinary Shares

The Directors total interests after these events are:

Director                             Resulting total interest

Steven Holliday                      535,184 Ordinary Shares
                                     Nil- B shares - unchanged

Roger Urwin                          1,235,141 Ordinary Shares
                                     B Shares- 58,397- unchanged

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


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