Dividend Reinvestment

National Grid plc ('National Grid')

7 January 2015

Notification of Directors' Interests

- Dividend Reinvestment

Following payment of the National Grid interim 2014/15 dividend on 7 January 2015, National Grid received notification on 7 January 2015 that the following purchases of National Grid ordinary shares to reinvest dividends had been made on behalf of Sir Peter Gershon and Lady Eileen Gershon, in London on 7 January 2015, at a price of 907.88 pence per share; 397 shares on behalf of Sir Peter Gershon and 69 shares on behalf of Lady Eileen Gershon.

National Grid received further notification today that Sir Peter Gershon acquired a joint interest with Lady Eileen Gershon of 772 ordinary shares in National Grid, in London on 7 January 2015, allotted under the terms of the Scrip Dividend Scheme at the Scrip Dividend Reference Price of 937.40 pence per share.

Following these changes Sir Peter Gershon has an interest in 79,450 ordinary shares in National Grid.

This announcement is made pursuant to the Disclosure and Transparency Rule 3.1.4.

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Contact: D Whincup, Company Secretarial Assistant

0207 004 3209