Holding(s) in Company

Monday 5thAugust 2013

National Grid plc (National Grid)

Notification of Major Interest in National Grid Ordinary Shares

National Grid has today noted receipt of a further notification on Form TR-1 from The Capital Group Companies, Inc. that its total interest in National Grid voting ordinary shares was, at 1 August 2013, at 10.9922%, a total of 403,430,699 shares (previously notified at 25 July 2013, at 11.045%, a total of 405,351,898 shares).

This notice is given in fulfilment of National Grid's obligations under the Disclosure and Transparency Rules.

D C Forward

Assistant Secretary

0207 004 3226