The financial deal for a new nuclear power station in Somerset is to be investigated by the European Commission, in a move that could delay.
Under the deal, announced by the Prime Minister last month, Hinkley C will be built by a French company which will receive a guaranteed price for its energy for 35 years - at twice the current level. The commission will investigate whether this complies with European rules on state aid.
David Cameron has insisted that plans for the UK's first nuclear power station in a generation at Hinkley was "not a deal at any price".
The Chancellor has given formal Government approval for Chinese state-run firms to buy into British nuclear power - should we be worried?