The announcement was made by chancellor George Osborne on a visit to China, since China General Nuclear Corporation and China National Nuclear Corporation are now partnering with France’s EDF Energy on the project.
The deal now clears the way for a final investment decision by EDF, which is expected within the next few weeks.
The agreement of guarantees also boosts work being carried out under a memorandum of understanding on fuel cycle collaboration signed with China in 2014, which the government believes has the potential to leverage UK expertise in nuclear waste management and decommissioning.
Chancellor George Osborne said: “Britain was the home to the very first civil nuclear power stations in the world and I am determined that we now lead the way again.
“Nuclear power is cost competitive with other low carbon technology and is a crucial part of our energy mix, along with new sources of power such as shale gas.
“So I am delighted to announce this guarantee for Hinkley Point today and to be in China to discuss their investments in Britain’s nuclear industry.
“It is another move forward for the golden relationship between Britain and China – the world’s oldest civil nuclear power and the world’s fastest growing civil nuclear power.”
Energy secretary Amber Rudd said: “New nuclear power is a vital part of our long-term plan to provide secure, clean energy supplies that hardworking families and businesses can rely on in the decades ahead. Today’s guarantee is an important step forward for the first new nuclear power station in a generation and the future of our home-grown energy supplies.”
EDF Energy chief executive Vincent de Rivaz said: “The chancellor’s approval of the infrastructure guarantee is a clear sign of the government’s commitment to Hinkley Point C. The government’s determination to bring about a renewal of infrastructure and to attract inward investment to the UK are demonstrated by this good news.
“It is further progress towards a final investment decision on a project which will provide reliable, affordable low carbon electricity for decades. We welcome the government’s support for the industrial participation by EDF and its Chinese partners.”
Documentation is subject to final approvals.