Peter Hain has warned of his concerns about a new generation of nuclear power stations, insisting that it would be "significantly preferable" to move toward renewable power.
He became the first cabinet opponent of nuclear power to break ranks in public, arguing that new nuclear power stations would have "vast" implications for security and unknown costs.
His comments contradict Tony Blair, who signalled his support for nuclear energy at the Labour Party conference, singling out nuclear power as an alternative to Britain's reliance on "unstable" regimes for its energy supplies.
Mr Hain makes his views clear in an article for the Socialist Environment Resources Association (Sera), a green group affiliated to the Labour Party which boasts support from nearly 60 MPs.
The article for the association's magazine New Ground argues the nuclear energy "must be on the table" but expresses deep concerns about security and costs. He writes that renewable energy "is significantly preferable to the widely advocated 'nuclear option'. While everything must be on the table during the review, serious concerns must remain about nuclear: the financial costs are impossible to estimate, security implications are vast, its label as 'clean' is unwarranted as uranium enrichment is carbon-emitting and we rely on other nations for its supply."
"Our failure to take the tough decisions on alternative sources of energy in the past has left us now facing this option. If we are faced with no choice but to go down this route, then we must at the same time make a similar commitment to renewables that ensures future generations do not face the same dilemma."
The Government's energy review, due to be published in June, is widely expected to announce a new nuclear programme.
Mr Blair is facing growing opposition in Labour ranks with an influential Labour green group that counts dozens of MPs among its members, warning ministers not to press ahead with the nuclear option when they publish the results of the Government's energy review.
Alan Johnson, the Secretary of State for Trade and Industry, and Malcolm Wicks, the Energy minister, will brief MPs on the review today.
But they will face scepticism from Labour MPs, many of whom believe Mr Blair has already decided to commission a new generation of nuclear power stations.
Opposition to such a move was also fuelled by the government's Sustainable Development Commission which said new nuclear power stations were not the answer to climate change or problems with the security of supply. A submission to the review by Sera, whose members also include the cabinet ministers Margaret Beckett, Charles Clarke, Ian McCartney and David Miliband, argues strongly against any new nuclear building programme, saying such a policy "cannot be part of a progressive energy policy".
Further criticism of the proposal will come from a study by Labour MPs opposed to new nuclear power stations due to be published later this month.
One of its authors, Colin Challen, the MP for Morley and Rothwell, said: "On the Labour benches there are more against it than for it. My view is that nuclear energy poses a great threat to our ability to deal with climate change. It would almost inevitably force out alternatives."
Alan Simpson, a member of the Socialist Campaign Group of Labour MPs, said: "Nuclear is likely to turn out to be the last of Blair's catastrophic misjudgements."
Meanwhile, the Conservatives called on the Government to press ahead with replacing Britain's ageing nuclear deterrent.
Liam Fox, the shadow defence secretary, said Trident must be replaced when it comes to the end of its life.Reuse content