National Grid : Publication of Supplementary Prospectus

Publication of Supplementary Prospectus

The following supplementary prospectus has been approved by the UK Listing Authority and is available for viewing:

The Supplementary Prospectus dated 10 January 2019 (the 'SupplementaryProspectus') supplementing the prospectus dated 2 August 2018 (as supplemented by the first supplement to the prospectus dated 23 November 2018 (together, the 'Prospectus')) for the National Grid plc and National Grid Electricity Transmission plc Euro 15,000,000,000 Euro Medium Term Note Programme.

The Supplementary Prospectus should be read and construed in conjunction with the Prospectus.

To view the Supplementary Prospectus, please paste the following URL into the address bar of your browser:

http://www.rns-pdf.londonstockexchange.com/rns/7880M_1-2019-1-10.pdf

A copy of the Supplementary Prospectus has been submitted to the National Storage Mechanism and will shortly be available for inspection at http://www.morningstar.co.uk/uk/

For further information, please contact:

Kwok Liu
Deputy Treasurer, Funding & Investment
National Grid plc
1-3 Strand
London WC2N 5EH

Tel: [phone]

Fax: [phone]

Sean Kemp
Media Relations
National Grid plc
Warwick House

Warwick Technology Park

Gallows Hill

Warwick

CV34 6DA

Tel: [phone]

Fax: [phone]

DISCLAIMER - INTENDED ADDRESSEES

Please note that the information contained in the Supplementary Prospectus may be addressed to and/or targeted at persons who are residents of particular countries (specified in the Prospectus) only and is not intended for use and should not be relied upon by any person outside these countries and/or to whom the offer contained in the Supplementary Prospectus is not addressed. Prior to relying on the information contained in the Supplementary Prospectus you must ascertain from the Prospectus whether or not you are part of the intended addressees of the information contained therein.

Your right to access this service is conditional upon complying with the above requirement.