Holding(s) in Company

9 June 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 5 June 2014, at 10.9788%, a total of 410,044,171 shares (previously notified at 8 January 2014, at 11.103%, a total of 414,173,676 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