# EDGAR Filing Document

**Accession Number:** 0001004315
**File Stem:** 0001654954-26-000549
**Filing Date:** 2026-1
**Character Count:** 5238
**Document Hash:** 725ddc367b9587e6d34d0f2e9f379d90
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001654954-26-000549.hdr.sgml**: 20260123

**ACCESSION NUMBER**: 0001654954-26-000549

**CONFORMED SUBMISSION TYPE**: 6-K

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260123

**FILED AS OF DATE**: 20260123

**DATE AS OF CHANGE**: 20260123

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** NATIONAL GRID PLC
- **CENTRAL INDEX KEY:** 0001004315
- **STANDARD INDUSTRIAL CLASSIFICATION:** NATURAL GAS TRANSMISSION [4922]
- **ORGANIZATION NAME:** 01 Energy & Transportation
- **EIN:** 980367158
- **FISCAL YEAR END:** 0331

**FILING VALUES:**
- **FORM TYPE:** 6-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-14958
- **FILM NUMBER:** 26553591

**BUSINESS ADDRESS:**
- **STREET 1:** 1-3 STRAND
- **CITY:** LONDON
- **STATE:** X0
- **ZIP:** WC2N 5EH
- **BUSINESS PHONE:** (44) 207 004 3220

**MAIL ADDRESS:**
- **STREET 1:** 1-3 STRAND
- **CITY:** LONDON
- **STATE:** X0
- **ZIP:** WC2N 5EH

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** NATIONAL GRID TRANSCO PLC
- **DATE OF NAME CHANGE:** 20021121

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** NATIONAL GRID GROUP PLC
- **DATE OF NAME CHANGE:** 19991007

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** NATIONAL GRID HOLDING PLC
- **DATE OF NAME CHANGE:** 19991007

**UNITED STATES**

 **SECURITIES AND EXCHANGE COMMISSION**

 **Washington D.C. 20549**

 **FORM 6-K**

 **REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16 UNDER THE SECURITIES EXCHANGE ACT OF 1934**

 **Date: 23 January 2026**

 **Commission File Number: 001-14958**

 **NATIONAL GRID plc**

(Translation of registrant's name into English)

 **England and Wales**

(Jurisdiction of Incorporation)

 **1-3 Strand, London, WC2N 5EH, United Kingdom**

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

☒ Form 20-F ☐ Form 40-F

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): ☐

Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3- 2(b) under the Securities Exchange Act of 1934. ☐ Yes ☒ No

If "Yes" is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): n/a

 **EXHIBIT INDEX**

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| | |
|:---|:---|
| **Exhibit No.**<br>| **Description**<br>|
| 99.1<br>| Exhibit 99.1 Announcement sent to the London Stock Exchange on 23 January 2026 — Publication of a Supplementary Prospectus |

---

Exhibit 99.1

 **23 January 2026**

 **National Grid plc / National Grid Electricity Transmission plc**

 **Publication of a Supplementary Prospectus**

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

 *The Supplementary Prospectus dated 23 January 2026 (the "**Supplementary Prospectus**") supplementing the prospectus dated 19 August 2025 (the "**Prospectus**") for the National Grid plc and National Grid Electricity Transmission plc Euro 20,000,000,000 Euro Medium Term Note Programme.*

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

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

 <u>http://www.rns-pdf.londonstockexchange.com/rns/2048Q_1-2026-1-23.pdf</u>

A copy of the Supplementary Prospectus has been submitted to the National Storage Mechanism and will shortly be available to the public for inspection at *<u>https://data.fca.org.uk/#/nsm/nationalstoragemechanism</u>*.

For further information, please contact:

---

| | |
|:---|:---|
| Kwok Liu | +44 (0) 7900 405 729 (m) |
| Deputy Treasurer, Funding & Investment<br> National Grid plc |  |
| Ben Davis | +44 (0) 7971 539999 |
| Senior Manager, Media & PR<br> National Grid plc |  |

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 **DISCLAIMER - INTENDED ADDRESSEES**

Please note that the information contained in the 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 Prospectus is not addressed. Prior to relying on the information contained in the 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.

 **SIGNATURE**

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

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| | |
|:---|:---|
| &nbsp;&nbsp;&nbsp; NATIONAL GRID plc | &nbsp;&nbsp;&nbsp; NATIONAL GRID plc |
|  ***By:***<br>|  ***Beth Melges***<br>|
|  | Beth Melges<br> Head of Plc Governance<br>|

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Date: 23 January 2026