EDF is building a new 3.2 gigawatt (GW) nuclear plant, Hinkley Point C, in south-west England. The project, initially slated for completion in 2017, has been plagued by delays and cost overruns.
This week EDF pushed back the start date of the plant to at least 2029 from the previous mid-2027 target, with a new estimated cost of between 31 billion and 34 billion pounds ($43.06 billion) based on 2015 values, up from an earlier, most recent 25-26 billion pound estimate.
EDF also plans to build another 3.2 GW nuclear plant, Sizewell C, in south-east England, but it has yet to receive a final investment decision.
Sources said there have been discussions between the two governments, with France pressing for a financial injection for both projects.
One of the sources said the French government holds the British government responsible for Chinese firm CGN stopping funding for Hinkley, where it is a 33.5% shareholder, after Britain took over CGN's stake in Sizewell C.
"Paris thinks that the British government is responsible for CGN's withdrawal and that it would therefore not be illogical for it to inject cash in HPC," the source said.
France's finance ministry and EDF, which was fully nationalised in 2023, declined to comment.
A second source said the lack of CGN funding for Hinkley Point was putting excessive pressure on EDF, which just has announced more delays and cost overruns.
A spokesperson at the UK Department for Energy Security and Net Zero said Hinkley Point C was not a government project.
"Any additional costs or schedule overruns are the responsibility of EDF and its partners and will in no way fall on taxpayers," the spokesperson said.
The UK government said on Monday it would invest an extra 1.3 billion pounds in Sizewell C, which comes on top of in a 700 million-pound funding pledge in 2022, as well as a further 511 million pounds agreed last summer.
A third source said cross-Channel discussions on the matter were on hold and a cooling off period was needed before talks could resume.
Last year, the UK government began looking for private investment in Sizewell C. It has been quiet on the matter since and the third source said the viability of the project could be at risk.
"We're starting from quite a long way apart ... so I think all scenarios should be considered."
Britain has announced plans to speed up new nuclear projects by introducing a time-frame requiring an investment decision every five years from 2030 to 2044 and to also explore the potential of another new large-scale nuclear plant.