Holding(s) in Company

10 January 2014

National Grid plc (National Grid)

Notification of Major Interest in National Grid Ordinary Shares

National Grid has received a notification on Form TR-1 from The Capital Group Companies, Inc. that its total interest in National Grid voting ordinary shares was, at 8 January 2014, at 11.103%, a total of 414,173,676 shares (previously notified at 1 August 2013, at 10.9922%, a total of 403,430,699 shares).

This notice is in compliance with National Grid's obligations under the Disclosure and Transparency Rules.

Alice Morgan

Assistant Company Secretary

0207 004 3228