Around 30,000 jobs may be created and a £60bn boost to the economy generated because of a UK-France nuclear energy deal agreed by the two countries' leaders.
Prime Minister David Cameron and his French counterpart, President Nicolas Sarkozy, are signing a declaration in Paris that will see an initial £500m of deals between French and British companies.
This will mean a new generation of nuclear power plants being built on British soil at sites in Somerset, Suffolk, Cumbria, North Wales and Gloucestershire, which will eventually generate billions of pounds for Britain.
While the potential for 30,000 new jobs will take time to come to fruition, 1,500 jobs will immediately be created as work starts on new facilities off the back of the deal.
Rolls-Royce and French energy company Areva reached a £400m deal that will see a new factory built in Rotherham, South Yorkshire, to supply services to the first new nuclear reactor to be built at Somerset's Hinkley Point.
"I want the vast majority of the content of our new nuclear plants to be constructed, manufactured and engineered by British companies," Cameron said.
"And we will choose the partners and technologies to maximise the economic benefits to the U.K. Today marks an important first step towards that - a good deal for Britain and a good deal for France."
Ed Davey, Britain's energy secretary, was also travelling with Cameron to Paris.
"We need hundreds of billions of pounds of investment in clean energy projects in the U.K. This will bring high-skilled job opportunities the length and breadth of the country," Davey said.