Company: NEWEN
Filing Date: 2025-08-27
Form Type: 6-K
Source: 0001654954-25-010066
Chunk: 0

Company: NATIONAL GRID PLC
Filing Date: 2025-08-27
Form: 6-K
Chunk 0
---
### UNITED STATES

### SECURITIES AND EXCHANGE COMMISSION

#### Washington D.C. 20549

#### FORM 6-K
<div align='center'>**REPORT OF FOREIGN PRIVATE ISSUER PURSUANT TO RULE 13a-16 OR 15d-16 UNDER THE SECURITIES EXCHANGE ACT OF 1934**</div>

#### Date: 27 August 2025

#### Commission File Number: 001-14958

#### NATIONAL GRID plc
<div align='center'>(Translation of registrant’s name into English)</div>

#### England and Wales
<div align='center'>(Jurisdiction of Incorporation)</div>

#### 1-3 Strand, London, WC2N 5EH, United Kingdom
<div align='center'>(Address of principal executive office)</div>

<div align='center'>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</div>

### EXHIBIT INDEX
| Exhibit No. | Description                                                      |
| 99.1        | Exhibit                                                          
 99.1 Announcement sent to the London Stock Exchange on 27 August 
 2025—                                                            
 Response to Ofgem's RIIO-ET3 Draft Determination                 |

Exhibit 99.1

#### 27 August 2025

#### National Grid plc
<div align='center'>**Ofgem's RIIO-ET3 Draft Determination: Consultation Response**</div>

As part of the ongoing process to agree the RIIO-ET3 price control which covers our National Grid Electricity Transmission business, we have submitted our response