The figure was described as shocking by critics of the scheme, who said it showed just how volatile and uncertain the project had become given the same energy department’s cost figure of 12 months earlier had been £14bn.

The latest prediction comes amid increasing speculation about the future of the controversial project in Somerset, now beset by worries about whether Brexit financial jitters could further undermine it.

Hinkley has been a flagship energy project for the British government and the chancellor, George Osborne, in particular, who lobbied hard and successfully for China to take a stake in the scheme.

Officials at the Department of Energy and Climate Change (DECC) on Thursday confirmed the £37bn figure but said it was a provisional, set in September 2015 when wholesale power prices were very low and would not affect bill payers. …

“… Critics of the scheme have claimed that the fall in the value of the pound since the referendum vote will increase the costs of the scheme to EDF’s French contractors, who work in higher cost euros. …

… The fall in power prices in the UK and continental Europe that have influenced the latest lifetime cost assessment for Hinkley is also responsible for some of the financial difficulties at EDF.

There have also been suggestions that Chinese investors are becoming more nervous about Hinkley and are demanding more concessions from EDF, so that more Chinese project managers and suppliers are involved. EDF denied this.”