Deferred Share Plan- 2012 Award

15 June 2012

National Grid plc (National Grid)

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Notification of Directors' Interests____________________________________________________________

Deferred Share Plan- 2012 Award

Today (15 June 2012) National Grid received a notification from ACS HR Solutions UK Limited, as Administrator of the National Grid Deferred Share Plan.The following Executive Directors were granted an award of Ordinary shares in National Grid (the 'Shares') or American Depositary Shares (ADSs) under the Plan on Thursday 14 June 2012, calculated by reference to a share price of 658.47p or an ADS price of $51.2887. The awards will vest on the third anniversary of the date of grant (June 2015). The shares will be transferred to participants net of deductions as soon as practicable thereafter.

Awards to the Executive Directors are as follows:

 Director Number of ADSs

Tom King 11,332

Number of Shares

Andrew Bonfield 55,150

Steve Holliday 75,933

Nick Winser 39,682

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