Total Voting Rights

1 June 2017

National Grid plc (National Grid)

Voting Rights and Capital Update

National Grid's registered capital as at 31 May 2017 consisted of 3,614,401,483 ordinary shares, of which, 173,239,075 were held as treasury shares; leaving a balance of 3,441,162,408 shares with voting rights.

The figure of 3,441,162,408 may be used by shareholders as the denominator for the calculations by which they will determine if they are required to notify their interest in, or a change to their interest in, National Grid under the FCA Disclosure Guidance and Transparency Rules.

Contact: C James, Company Secretarial Assistant, (0207 004 3116).