Sir Keir Starmer promised there would be no more “dithering” about backing nuclear power as the Government committed to the Sizewell C plant and the development of new small modular reactors (SMRs).
The Prime Minister said the “change of mindset” would help free the UK from reliance on international fossil fuel markets and prevent price spikes such as those in the wake of Vladimir Putin’s invasion of Ukraine.
Chancellor Rachel Reeves signed off on £14.2 billion of investment to build the new Sizewell C nuclear plant in Suffolk, while Rolls-Royce has been named as the preferred bidder to build SMRs in a programme backed by £2.5 billion of taxpayers’ cash.
Speaking at a college in Ipswich, Sir Keir said successive governments had “dithered and delayed” over nuclear power.
He said: “The last reactor was 1995, 30 years ago, and I think that was Sizewell B.
“So here, to put this down today, is really important. It’s not just an important decision for the future, it’s a change of mindset.
“No more dithering, no more delay, no more being unclear about what we’re going to do, a real statement of intent as we go forward.”
He added: “Having our own energy in this country that we control, gives us security, gives us independence, so Putin can’t put his boot on our throat.
“And it means that we can control the prices in a way that we haven’t been able to in recent years, which has meant very high prices for businesses, for households and for families.”
Officials hope SMRs will be cheaper and quicker to build than traditional power plants, and projects could be connected to the grid by the mid-2030s.
Ms Reeves said: “The UK is back where it belongs, taking the lead in the technologies of tomorrow with Rolls-Royce SMR as the preferred partner for this journey.”
Speaking at the GMB union’s congress in Brighton, she said: “This Labour government is investing in the biggest rollout of nuclear power in a generation.”
The SMR project could support up to 3,000 new skilled jobs and power the equivalent of around three million homes, with a first site expected to be allocated later this year by state-owned Great British Energy – Nuclear.
Tuesday’s announcement of Rolls-Royce as the preferred bidder came after the Government confirmed financial support for Sizewell C.
Ms Reeves said: “This Government is giving our full backing to the Sizewell C nuclear plant, providing £14.2 billion of additional funding for the first directly state-funded nuclear power station since 1988.”
Trade unions welcomed the Sizewell move, which the Treasury said would go towards creating 10,000 jobs, including 1,500 apprenticeships.
But the head of a campaign group opposing the plant criticised the decision to commit the funding, saying it is still not clear what the total cost will be as the final investment decision has not yet been announced and the Government is still seeking private investment.
Nuclear plants are seen as increasingly important electricity sources as the Government tries to decarbonise Britain’s grid by 2030, replacing fossil fuels with green power.
The joint managing directors of Sizewell C, Julia Pyke and Nigel Cann, said: “Today marks the start of an exciting new chapter for Sizewell C, the UK’s first British-owned nuclear power plant in over 30 years.”
At the peak of construction, Sizewell C is expected to provide 10,000 jobs and the company behind the project has already signed £330 million worth of contracts with local businesses.
The plant, which will power the equivalent of six million homes, is planned to be operational in the 2030s.
We're ushering in a new golden age of nuclear with a £14.2bn investment in Sizewell C.
— HM Treasury (@hmtreasury) June 10, 2025
The funding will help to provide clean power for millions of homes and create 10,000 jobs and 1,500 apprenticeships.
We're investing in Britain’s renewal to deliver on our Plan for Change. pic.twitter.com/eBiXlQ1U1d
The GMB union said giving Sizewell C the go-ahead was “momentous”.
Regional secretary Warren Kenny said: “Sizewell C will provide thousands of good, skilled, unionised jobs and we look forward to working closely with the Government and Sizewell C to help secure a greener future for this country’s energy sector.”
Unite general secretary Sharon Graham said the announcements were “vital” for energy and construction jobs but called for the Government to go further and commit to building a new nuclear power station at Wylfa in Wales.
But Alison Downes, of Stop Sizewell C, said ministers had not “come clean” about the full cost of the project, which the group have previously estimated could be some £40 billion.
The £14.2 billion comes on top of £3.7 billion already committed to the project.
Ms Downes said: “With the continued secrecy about Sizewell C’s total cost, how can voters decide whether the £18 billion pledged to Sizewell C is a good use of their money?
“There is no dispute the project will add to consumer bills during construction, and it is virtually guaranteed to be late and overspent just like Hinkley C.”
Sir Keir told the BBC his Government is not writing a “blank cheque” with taxpayer money to fund Sizewell C and that there are “lessons to learn” from Hinkley Point C.
He also said there are “regulations in place” to protect the environment as the plant is built.
The Government has also promised £2.5 billion over five years for fusion energy research and £6 billion of investment for the industrial base supporting the Royal Navy’s nuclear submarine fleet.
The Conservatives branded the Government’s nuclear development plans as a “downgrade” on the previous government’s commitments.
Tory frontbencher Nick Timothy told the Commons: “This statement is a downgrade on what the last government put in motion.
“Today, the Energy Secretary has announced only one small modular reactor (SMR). There is no clear target to increase nuclear power generation, and no news on Wylfa.”
The Energy Secretary responded: “I do sort of slightly scratch my head, because he sort of says it’s a downgrade, I mean, we’ve announced the largest nuclear building programme in 50 years.”
