EX-5.2

Exhibit 5.2

Linklaters LLP

1290 Avenue of the Americas

New York, NY 10104

Telephone (+1) 212 903 9000

Facsimile (+1) 212 903 9100

National Grid plc

1-3 Strand

London WC2N 5EH

England

January 11, 2024

Ladies and Gentlemen,

Issue by National Grid plc (the “Issuer”) of U.S.$750,000,000 5.418% Notes due 2034 (the “Debt Securities”)

We have acted as United States counsel to the Issuer in connection with the issuance of the Debt Securities by the Issuer. The Debt Securities are being issued pursuant to the Indenture dated as of June 12, 2023, as amended and supplemented from time to time (the “Base Indenture”), as supplemented by a second supplemental indenture dated as of January 11, 2024 (the “Second Supplemental Indenture”, and together with the Base Indenture, the “Indenture”) between the Issuer and The Bank of New York Mellon, London Branch, as trustee (the “Trustee”).

This opinion is limited to the federal law of the United States and the laws of the State of New York, and we express no opinion as to the effect of the laws of any other State of the United States or any other jurisdiction.

For the purpose of this opinion, we have examined the Indenture, such certificates and other documents, and such questions of law, as we have considered necessary or appropriate. We have assumed that the Issuer has the power to execute and deliver the Debt Securities and the Indenture, and perform its obligations thereunder, that the Indenture has been duly and validly authorized, executed and delivered under the laws of England and Wales by the Issuer, that the Debt Securities have been duly and validly authorized and delivered under the laws of England and Wales by the Issuer, that the Debt Securities conform to the form examined by us and that the signatures on all documents examined by us are genuine, assumptions that we have not independently verified.

In our opinion, the Debt Securities have been duly executed, authenticated, issued and delivered and constitute valid and legally binding obligations of the Issuer, enforceable in accordance with their terms, subject to bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws of general applicability relating to or affecting creditors’ rights and to general equity principles.

This communication is confidential and may be privileged or otherwise protected by work product immunity.

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