EDF Energy says Hinkley C will not be affected by the withdrawal today of a major backer.

Centrica, which owns British Gas, took an option for a 20% stake in nuclear new build at Hinkley Point and Sizewell in 2009, but is pulling out because it says pre-development spend on the project is nearing an agreed £1billion cap.

Sam Laidlaw, Centrica chief executive, said: “Since our initial investment, the anticipated project costs in new nuclear have increased and the construction timetable has extended by a number of years.”

In response, EDF said it respected Centrica's decision, but added: “Momentum behind EDF Energy's new nuclear project at Hinkley Point C in Somerset remains strong.

“EDF Energy was prepared for this decision and understands that the profile and scale of this investment may not meet Centrica's shareholders' current expectations and priorities.”

Centrica's 20% stake in the eight existing UK nuclear power stations is unaffected.

The Government is expected to decide within weeks whether or not Hinkley C can go ahead.