Holding(s) in Company

5th April 2013

National Grid plc (National Grid)

Notification of Major Interest in National Grid Ordinary Shares

National Grid today 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 3 April 2013, at 11.02%, a total of 404,063,006 shares (previously notified at 21 February 2013 at 10.905%, a total of 399,638,038 shares).

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

D C Forward

Assistant Secretary

0207 004 3226