Director/PDMR Shareholding

National Grid PLC
29 June 2007

29th June 2007

National Grid plc (National Grid)

Notification of Changes in Directors' Interests

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Performance Share Plan

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On 28 June 2007, the following directors were granted an award of Ordinary
shares in National Grid plc (the 'Shares') under the National Grid Performance
Share Plan, calculated by reference to a share price of 740.75p. The extent to
which awards will vest will depend upon the company's performance against the
relevant conditions. Subject to performance, the shares will vest in June 2010
and will be transferred to participants net of deductions on 28 June 2011.

            Director                      Number of Shares
1.        Mr E M Astle                                                    74,249
2.        Mr S J Holliday                                                139,217
3.        Mr S C B Lucas                                                  84,930
4.        Mr M Fairbairn                                                  67,499
5.        Mr N P Winser                                                   75,008



The total share interests of the above directors, following these changes, are:



Director                      Number of Shares
1.        Mr E M Astle                                                   702,623
2.        Mr S J Holliday                                                716,970
3.        Mr S C B Lucas                                                 616,592
4.        Mr M Fairbairn                                                 324,865
5.        Mr N P Winser                                                  510,786

The directors' holdings in B Shares in National Grid plc remain unchanged.


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