Holding(s) in Company

23 October 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 21 October 2014, at 8.960%, a total of 337,726,282 shares (previously notified at 8 September 2014, at 9.991%, a total of 376,821,276 shares).

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

David Whincup

Company Secretarial Assistant

0207 004 3209