Campaigners have raised questions after it was reported funding for a new nuclear power station on the Suffolk coast is to be signed off by ministers within a fortnight.

Funding for the £20billion Sizewell C plant is set to be approved by the government by next month, paving the way for private investment, according to The Telegraph.

The decision would be a major boost for EDF Energy, which is said to be in advanced talks with the government over further cash to move the scheme forward ahead of a final investment decision next year.

The government is seeking to end the role of Chinese state company China General Nuclear in the project because of security concerns, which means it is more reliant on money from other backers.

The news comes after a warning from trade unions this week that the Sizewell C project may be at risk if delays to decisions around government funding continue.

One of the government's top climate advisors also raised doubts this week over the competence of EDF to deliver projects and called the proposed plan for Sizewell C "ridiculous".

Lord Deben, who chairs the climate change committee and lives in Suffolk, was accused of being a NIMBY by EDF after he made the comments, The Times reported.

In May, EDF revealed the nuclear power station it is building at Hinkley Point in Somerset will start operating a year later than planned and will cost an extra £3bn.

Campaign group Stop Sizewell C has asked how much the project will cost via a new set of advertisements on the tube at Westminster.

Reacting to the funding news, Alison Downes, from the group, said: "Why do ministers appear willing to throw more cash at Sizewell C, despite the risk and questionable value for money, when there is none for hard stretched workers and - as Lord Deben pointed out - when the nuclear industry 'doesn’t deliver things on time and it doesn’t deliver them to budget'?

"Nobody is even owning up to how much Sizewell C would cost: the last estimate is more than two years out of date."

A funding deal is not expected until after planning consent for Sizewell C is granted, with the deadline for that decision set for July 8.