"A weakness has been discovered in a French nuclear reactor of the type set to be built at Hinkley in the UK.
France's nuclear safety regulator told the BBC the flaw in the steel housing the reactor core at the nuclear plant being built in Normandy is "serious".
He added that unless he was satisfied with the plans to put it right, he could stop the project.
The fault in the French reactor is thought to be a construction fault, not an inherent weakness in the design."
Rob Broomby reports for BBC News July 9, 2015.