Representing the largest funding package to date, the cash will allow early construction works to continue ahead of a final investment decision later this year.

The funding from existing budgets will support ongoing preparatory works such as improvements to roads and rail lines around the Suffolk site, ensuring the necessary local infrastructure is in place before full construction begins.

Committing further government support at this stage will help the project stay on schedule and keep down overall costs.

The Development Consent Order (DCO) triggered by Sizewell C on 15 January gave the formal green light for construction to begin and released £250m funding for initiatives for the local community and environment.

Investing an additional £1.3 billion consolidates the government’s position as the majority shareholder in the project.

It follows a £700m funding pledge in November 2022 and a further £511m agreed last summer.

Julia Pyke, joint managing director at Sizewell C, said: “The funding means we can step up activity in Suffolk and deliver on our commitments to local communities.

“Sizewell C will build on the huge contribution of Hinkley Point C in restarting nuclear construction in Britain.

“It will bring another big boost to British nuclear skills and training, putting the industry in an even better position to deliver the other projects this country needs for its low carbon future.”

In addition to the 500 people employed so far, Sizewell C has plans to award 70% of the value of construction to UK businesses, helping to create thousands of jobs in Suffolk and nationwide.

The project will also create 1,500 apprenticeships, helping to build the skills base to support the UK’s long-term plans for new nuclear.

Once operational, the plant will generate 3.2GW of electricity, equating to 7% of the UK’s needs and enough to power up to 6 million British households for over 60 years.