Boris Johnson and Chancellor Nadhim Zahawi are also thought to be on board, as is Business Secretary Kwasi Kwarteng. However, other allies of Liz Truss are concerned that making a quick choice will restrict the future administration’s options.

In the next weeks, government funding for a new multibillion-pound nuclear power facility in Suffolk is anticipated to be approved.

Whitehall sources said that it was uncertain whether the government’s investment decision on Sizewell C will be made before the change in the prime minister, but confirmed that the project is likely to be approved.

This financing is comprised of an initial pot of around £1.7 billion from existing budgets.

The incoming prime minister is expected to make a final investment decision early the following year, which might result in the government investing several additional billions in the new facility.

Boris Johnson and Chancellor Nadhim Zahawi are also thought to be on board, as is Business Secretary Kwasi Kwarteng.

Mr. Kwarteng, who is expected to become chancellor in a coalition led by Liz Truss, wrote in The Mail on Sunday that the government should “push ahead with further nuclear power facilities” to strengthen Britain’s energy security.

However, other allies of Elizabeth Truss appear to be concerned that announcing the choice within the next two weeks will bind the hands of the incoming administration.

Treasury Secretary Simon Clarke wrote in a letter leaked to The Sunday Times that the costs of Sizewell C are “sufficient to meaningfully alter spending and fiscal choices for a new government, particularly in the context of broader constraints on the public finances.”

According to government sources, Mr. Clarke was operating in his capacity as secretary of the Treasury, and the final decision on Sizewell C will be made by the incoming administration.

Mr. Johnson, who is virtually a caretaker prime minister, had stated that he would not make any important decisions before leaving office.

Ms. Truss, the favorite to replace Mr. Johnson on 6 September, has proposed tax cuts, including a £30 billion per year rollback of the national insurance increase.

However, she is under increasing pressure to provide additional assistance to the most disadvantaged, as experts warn that the energy price cap could exceed £6,000 in April, resulting in a further painful increase.

July saw the approval of Sizewell C’s development, but negotiations continued over the financial investment choice.

A government official stated, “Nuclear energy plays a crucial part in our efforts to lessen our dependency on fossil fuels and our susceptibility to volatile global gas prices.”

“Sizewell C negotiations are currently ongoing, and because they are active and commercially sensitive, we cannot comment further.”