Holding(s) in Company

20 April 2015

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 16 April 2015, at 3.881%, a total of 145,094,617 shares (previously notified at 18 February 2015, at 4.981%, a total of 187,283,805 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