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.
The Government has given the go ahead to build Britain's first new nuclear power station in a decade at Hinkley Point near Bridgwater.
Speaking today David Cameron said: "I think this is a really important day for our country, the day when we have agreed to build a new nuclear power station, I hope the first of many nuclear power stations here at Hinkley Point, Hinkley Point C."
The Prime Minister has given the go-ahead for Britain's first new nuclear reactor for a generation.
Hinkley C will become the single largest construction project in the UK, it will take ten years to deliver, and will cost billions.
Laura Makin-Isherwood has been speaking to people in the community about how they have responded to the news.
Rupert Cox from the Somerset Chamber of Commerce said at the peak of engineering, 5,500 people will be needed to work on the Hinkley Point C site.
He added, "that's nearly as many people that are on job seekers allowance at the moment in Somerset".
Richard Lloyd from the consumer association Which? said millions of consumers will be wondering what today's announcement on the Hinkley power station will mean for them.
He said: "There has been no transparent independent scrutiny of the price that the Government has signed up to on our behalf to pay, there needs to be a claw back if they've over paid and there needs to be a much more independent robust scrutiny of these deals."
Campaign group Stop Hinkley has staged a protest outside EDF offices in Bridgwater against the building of a new nuclear power station at Hinkley Point.
These time-lapse pictures from the protest group show campaigners putting up banners outside the office.
The government has given the go ahead to build Britain's first new nuclear power station in a decade at Hinkley Point near Bridgwater.
The announcement will see an investment of £16 billion, and the creation of 25,000 jobs.
As part of the deal, the government has agreed a so-called strike price with EDF for the amount it gets per megawatt hour of electricity.
The figure settled on today is £92.50 which is more than double the current market rate, the Prime Minister said it was a good deal.
The Prime Minister and the Energy Secretary have been taken on a tour around the Hinkley site where Britain's newest nuclear power plant will be built.
A video produced by EDF energy showing a CGI fly-through over the new Hinkley Point nuclear station allows people to go on a "virtual visit" of the site.
Today the Prime Minister confirmed that Britain's first new nuclear reactor for a generation will go ahead.
Hinkley C will become the single largest construction project in the UK, it will take 10 years to deliver and will cost billions.