Campaigners are set to challenge the government’s approval of the new Sizewell C nuclear power station in the High Court.

Together Against Sizewell C (TASC) has written to Kwasi Kwarteng, Secretary of State for Business, Energy and Industrial Strategy, stating they believe the decision was unlawful and raising concerns about the maintenance of a water supply and the resilience of the coastline. This letter is the start of the judicial review process which could culminate in a case before the High Court.

In July, the Government gave the go-ahead for the £20bn project, which is set to provide power for six million homes once it has been completed.

Ground could be broken for the scheme as early as next year once the final funding has been agreed.

The provision of fresh water to the site was one of the key issues raised by the Planning Inspectorate when considering the plans.

TASC chair Pete Wilkinson described the project as a "scandalous attack on the Suffolk environment".

He added: “The case against Sizewell C is overwhelming, as has been carefully documented throughout the inquiry stage and was found by the Planning Inspector to have merit.

“Even to consider building a £20bn+ nuclear power plant without first securing a water supply is a measure of the fixation this government has for nuclear power and its panic in making progress towards an energy policy which is as unachievable as it is inappropriate for the 21st-century challenges we face.”

However, a Sizewell C spokeswoman said: “In the first nine-to-12 months of construction, water will be supplied to the site using water tankers.

“After that, water will be supplied using a desalination plant which will draw its water from the North Sea.

“Northumbrian Water has committed to providing a permanent supply to the project and is aiming for this to be in place by the late 2020s.

“Should this not become available until later, the desalination plant could continue to operate throughout the construction phase. The government was satisfied with the water plan during construction and with the long-term plan.”

With regard to the coastline, she added: “When considering plans in place for coastal process and flooding the Planning Inspectorate was satisfied that the necessary monitoring and mitigation to manage any risks would be in place to 'secure the long-term sustainability of the coastal area' and that Sizewell C had fully addressed the flood risk associated with the project.”

Of the overall decision, she said: "Sizewell C was granted planning consent in July. The planning inspectorate decided that the benefits of the project will strongly outweigh the potential impacts.

"It agreed that Sizewell C would make a very substantial contribution to our future energy requirements.

"The application noted the very substantial benefits relating to the local economy and business and the significant employment and skills opportunities both during construction and operation of the station."

Additional information requested by the Secretary of State during the planning process, particularly about the water situation, was provided, the spokeswoman added.

This was taken into consideration when the final decision was made in July.

The Sizewell C project is set to be funded through the Regulated Assets Base (RAB) model, under which developers can add a small amount to electricity bills to cover the cost of construction, with the aim to eventually lower bills for consumers once the power station is up and running.

Suffolk Coastal MP Therese Coffey has also written to Mr Kwarteng calling for a judicial review, with particular concerns that the decision had been granted against the recommendations of the Planning Inspectorate.