Holding(s) in Company

Monday 25th February 2013

National Grid plc (National Grid)

Notification of Major Interest in National Grid Ordinary Shares

National Grid received, late on Friday 22nd February UK time, 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 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