"The start of electricity generation for Unit 1 is targeted for June 2027, the risk of further delay of the two units is assessed at 15 months, assuming the absence of a new pandemic wave and no additional effects of the war in Ukraine," EDF said in a statement adding that costs were now estimated between pound25 billion ($31 billion, 30 billion euros) and pound26 billion.

"During more than two years of the Covid-19 pandemic, the project continued without stopping. This protected the integrity of the supply chain and allowed the completion of major milestones. However, people, resources and supply chain have been severely constrained and their efficiency has been restricted.

"In addition, the quantities of materials and engineering as well as the cost of such activities, including, in particular marine works have risen."

Hinkley Point, in southwest England, is Britain's first new nuclear power plant in more than two decades.

Britain has a total of 15 nuclear reactors at eight sites around the country, but many of them are now approaching the end of their lifespan.