Director/PDMR Shareholding

18 June 2013

National Grid plc (National Grid)

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Notification of Directors' Interests____________________________________________________________

National Grid Deferred Share Plan- 2013 Award

Yesterday (17 June 2013), National Grid received notification from UBS Trustees (Jersey) Limited, as Trustee of the trust operating in conjunction with the National Grid Deferred Share Plan ("DSP"), that the following Executive Directors were granted an award of Ordinary shares in National Grid (the 'Shares') or American Depositary Shares (ADSs) under the DSP on Thursday 13 June 2013, calculated by reference to a share price of 740.92p or an ADS price of $57.972. The awards will vest on the third anniversary of the date of grant (June 2016). The Shares and ADSs will be transferred to participants net of deductions as soon as practicable thereafter.

Awards to the Executive Directors are as follows:

DSP-2010 Award Release

Earlier today, National Grid received notification from UBS Trustees (Jersey) Limited, as Trustee of the National Grid Group Employee Share Trust (the 'Trust'), confirming that the 2010 awards made to Executive Directors under the DSP were released on 17 June 2013 being the first business day after the third anniversary (15 June 2013) of the date of the awards in accordance with the plan rules. The number of shares disclosed below that have been transferred to participants by the Trustee are net of shares sold to cover statutory deductions and associated costs.

The Shares and ADSs released to Executive Directors are as follows:

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