Outgoing British Prime Minister Boris Johnson has approved funding for a new nuclear power plant, PA Media reports.

Whitehall sources have confirmed that Prime Minister and Chancellor Nadhim Zahawi has approved funding for the construction of the Sizewell C nuclear reactor in Suffolk.

The project, which is estimated at £20-30 billion, will receive private funding.

The government will make a final decision on public investment early next year, with it expected to buy a 20% stake in the plant, worth up to £6bn.

Business Secretary Kwasi Kwarteng, who is tipped to be Chancellor if Liz Truss wins the Conservative Party leadership race, is largely behind the plan.

There is no unity in the Truss camp on this issue, and the chief secretary of the treasury, Simon Clark, expressed concern to Johnson and Zahawi.

In a letter leaked to the Sunday Times, Clarke suggested that the action now would tie the hands of their successors.

Clark said that the costs of Sizewell C are sufficient to materially affect the spending and fiscal choices of the new government, especially in the context of broader pressure on public finances.

As essentially an interim prime minister after being forced to resign due to a series of scandals, Johnson has previously said he will not make major decisions until he leaves office.

In turn, Truss, the bidder to replace Mr Johnson on September 6, has vowed to cut taxes, including reversing a National Insurance hike that will cost at least £30bn a year.

But it is under increasing pressure to further support the most vulnerable as experts warn that the price cap for electricity could top £6,000 in April, another painful hike.

The approval for the construction of Sizewell C was received by Kvarteng in July, but talks over a financial investment decision are ongoing.