Transaction in Own Shares

3 January 2018

National Grid plc ("National Grid")

ISIN Code: GB00BDR05C01

Transaction in Own Shares

National Grid announces that it has purchased the following number of its ordinary shares of 12204/473p each on the London Stock Exchange from Barclays Capital Securities Limited ("Barclays") as part of its buy-back programme announced on 9 October 2017. The sole purpose of the programme is, as previously announced, to reduce the share capital of National Grid as part of the return of proceeds to shareholders following the sale of a majority interest in National Grid's UK gas distribution business.

National Grid intends to hold the purchased shares in treasury. Following the purchase of these shares, National Grid holds 245,254,036 of its ordinary shares in treasury and has 3,372,316,089 ordinary shares in issue (excluding treasury shares).

A schedule of individual trades carried out by Barclays (BARCGBN1) as principal in connection with the above purchases on 3 January 2018 is set out below.

Schedule of purchases - aggregate information

This announcement will also be available on National Grid's website at http://investors.nationalgrid.com/rns.aspx. 

Enquiries to:

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