The parent company behind the new Sizewell C nuclear power station has revealed an underlying loss of £4.44bn due to a decline in nuclear output, mainly in France.

However, EDF Energy's UK arm registered an underlying profit of £1.12bn in 2022, compared with a loss of £21m in 2021, mainly due to improved performance in nuclear energy output.

The firm's UK consumer energy supplier lost more than £200m in the year as the cost of buying energy was higher than the prices set by the Government's energy price cap, which limits the average household cost of energy and gas to £2,500 annually.

But the problems in France caused by a decline in nuclear output due to stress corrosion, along with the price caps on charges to consumers, had resulted in the firm buying electricity at a time when market prices were high.

This led to the fall in overall profits.

EDF's chief executive Luc Remont said: "The 2022 results were significantly affected by the decline in our electricity output, and also by exceptional regulatory measures introduced in France in difficult market conditions.

"Despite all the challenges, EDF actively focused on service and support for all its residential and business customers and made every endeavour to ensure the best generation fleet availability for the winter period."

He added the 'priority' was to improve EDF's financial position and he was 'confident' that actions taken to address the situation would bring benefits in 2023.

A spokesperson for Sizewell C said: "The results do not impact the Sizewell C project."

In the autumn, chancellor Jeremy Hunt announced in the budget that the Government would be providing £700m towards the £25bn cost of Sizewell C.

The two turbine reactor aims to generate low-carbon energy for six million homes over the next 60 years.

Alison Downes, spokesperson for campaign group Stop Sizewell C, which is opposed to the project, said: "EDF now admits that Hinkley Point C is expected to cost over £32bn in today's money and there are still almost five years of construction to go.

"Government officials have admitted privately that they expect Sizewell C to cost more than £30bn and here is that proof.

"With offshore wind at least five times cheaper, the Treasury should take note and save us from yet another expensive mistake."