Union leaders say they are backing plans for Sizewell C because of worries over potential energy gaps when the wind is not strong enough to generate electricity.

Prospect union, along with TUC, Unite and GMB, are also supporting the nuclear power station project because of the jobs it would bring and the millions of pounds it would pump into the economy each year.

EDF Energy is set make its application for consent next year for the project, which will create 6,000-plus jobs during construction and 900 jobs when the station is operational. Estimates say the project will be worth £100m a year during construction and then £40m a year in operation.

Representatives from the four unions - Sue Ferns, Prospect's senior deputy general secretary, Paul Nowak of the TUC, Justin Bowden of GMB, and Miles Hubbard, Unite - yesterday visited EDF Energy's coastal complex to show their support and discuss future funding options for Sizewell C.

Sue Ferns said: "EDF is the only company in the UK currently building new nuclear capacity. Prospect research shows that without new nuclear we face a potential energy gap during high demand low wind periods of up to 21%, so it is vital that we get this right.

"New build nuclear projects like Sizewell C will also create thousands of jobs and inject hundreds of millions of pounds into the economies of their local communities. That's why we unions are here today - to show our support for Sizewell C and urge the government to learn the lessons of this and Hinkley C and get on with building much needed capacity.

"Direct public procurement would be the cheapest way to fund new nuclear, but an infrastructure spending commitment on this scale is unlikely under the current government. The RAB model is not perfect but in current circumstances it is the most practicable way forward and should be supported as nuclear has a vital role to play in delivering net zero."

Mr Nowak added: "Trade unions are committed to fight against climate change. That means modernising our energy mix to help us reach net zero. Modern nuclear has an important role in this, alongside renewables like wind and solar.

"A greener economy must be a fairer economy too. Employers and government must work with unions to make sure that projects like Sizewell C deliver good quality, sustainable jobs. There should be high quality apprenticeships for the next generation of workers. And there should be opportunities to retrain and transfer for workers in sectors that face disruption as we decarbonise the economy."