"Nuclear is part of the answer," the Prime Minister said last night as he gave the green light for a new generation of power stations.
He was speaking as Trade and Industry Secretary Alistair Darling launched the Government's Energy Review in the House of Commons.
Mr Darling said: "New nuclear power stations could make a significant contribution to meeting our energy policy needs."
The proposals also include a fivefold increase in the use of renewable energy, with reforms to the planning laws to make it easier to build wind farms.
The Government will also focus on reducing energy consumption, working with businesses including hotels and supermarkets to help them cut fuel bills, and attempting to encourage the design of energy-efficient electrical goods.
But despite a range of measures likely to appeal to environmentalists, the announcement prompted an immediate outcry.
A group of Labour MPs, including Stoke North MP Joan Walley, warned: "We do not believe nuclear power is the solution - it is costly, risky and leaves a legacy of dangerous waste."
The MPs said: "We are concerned that investment in this technology could divert resources from improving e nergy efficiency and d eveloping renewable s upplies and micro generation."
But Mr Blair made the Government's position clear, as he visited an offshore wind farm off the picturesque north Kent coast.
He said: "We have to at least replace our nuclear p ower stations. These decisions have to be taken now. Fifteen years down the line we have got high energy prices and real problems.
"Everyone will concentrate on nuclear but one of the reasons for coming here is to say nuclear is part of the answer, it's not the only answer."
The private sector will be expected pay the costs of building and operating new nuclear plants.
An Energy White Paper in 2003 said better efficiency and investment in renewable forms of energy was the way ahead for the UK.
But the Prime Minister ordered a review last November, saying a fresh look was needed at how the UK could ensure it had a secure energy supply.
Mr Blair has been accused of prejudging the review by saying that nuclear power was back on the agenda with a "vengeance".
The proposals as a whole could save up to 25 million tonnes of carbon by 2020, on top of savings already planned, Mr Darling said.
The Government would change the law to ensure local opposition could not block new energy facilities, he warned.
"We'll be acting to ensure that energy companies, whether seeking to build gas storage facilities, wind farms or any other kind of large energy installation, are not faced with costly uncertainties and delay.
"Local concerns about specific sites must be taken into consideration but the right balance has to be struck with the national need for our vital energy infrastructure."
Tory Shadow Industry Secretary Alan Duncan said the Government had failed to make decisions to secure Britain's energy supply after nine years in power.
He said: "We have been told for months that urgent decisions must be made now, that delaying these decisions would risk the lights going out.
"Yet the Review puts off making any of the big decisions and instead proposes new consultations and areas to consider.
"The responsible thing to do is to give green energy a c hance, to unleash the potential of renewables and keep nuclear as a last resort."