1 December 2009 

National Grid plc (National Grid)

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Notification of Directors' Interests
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Special Retention Award Plan

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On 29 November 2007, Tom King was granted an award over 35,487 National Grid American Depository Shares ("ADS"s) under the National Grid Special Retention Award Plan (the "Plan"). This award was calculated by reference to a share price of $84.5360 per ADS and is vesting in three equal tranches on 29 November in 2008, 2009 and 2010 respectively. The ADSs below are being transferred to Mr King in accordance with the rules of the Plan.

On 30 November 2009 the second tranche of the award over 11,829 ADSs became due for release. The trustee has notified the Company that following the sale of 4,130 ADSs to meet US statutory deductions he retains 7,699 ADSs following their release to him, effective Monday 30 November 2009.

Following this release his total interest is 151,994 ADSs (equivalent to 759,970 National Grid ordinary shares).

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