Building new nuclear plants is not the answer to tackling climate change or securing Britain's energy supply, a government advisory panel has reported.
The UK's ageing nuclear plants are being phased out
The Sustainable Development Commission (SDC) report says doubling nuclear capacity would make only a small impact on reducing carbon emissions by 2035.
The body, which advises the government on the environment, says this must be set against the potential risks.
The government is currently undertaking a review of Britain's energy needs.
It regards building nuclear capacity as an alternative to reliance on fossil fuels such as coal, oil and gas.
As North Sea supplies dwindle, nuclear is seen by some as a more secure source of energy than hydrocarbon supplies from unstable regimes. Proponents say it could generate large quantities of electricity while helping to stabilise carbon dioxide CO2 emissions.
But the SDC report, compiled in response to the energy review, concluded that the risks of nuclear energy outweighed its advantages.
Jonathon Porritt, chairman of the SDC, commented: "There's little point in denying that nuclear power has benefits, but in our view, these are outweighed by serious disadvantages.
"The government is going to have to stop looking for an easy fix to our climate change and energy crises - there simply isn't one."
He said that the SDC had concluded that the long-term target of reducing carbon dioxide emissions could be met without nuclear power.
Energy minister Malcolm Wicks, who is leading the government's review, said the SDC's findings made an "important and thorough contribution" to the debate.
The report does not rule out future research on nuclear
"Securing clean, affordable energy supplies for the long term will not be easy. No one has ever suggested that nuclear power - or any other individual energy source - could meet all of those challenges," Mr Wicks said.
"As the commission itself finds, this is not a black and white issue. It does, however, agree that it is right that we are assessing the potential contribution of new nuclear [plants]."
The Nuclear Industry Association (NIA), the representative body for the UK's nuclear sector, gave the report a more cautious welcome.
Philip Dewhurst, chairman of the NIA, said the SDC report was not as negative as it had feared.
"What the report is basically saying is that the government has got to make a choice between renewables and nuclear.
"The SDC is saying you cannot have both, but of course you can. We support having both renewables and nuclear," he told the BBC News website.
"The key factor about nuclear is its base load which means it keeps working 24 hours a day, seven days a week. Everyone would agree that some renewable technologies are intermittent at best."
Research by the SDC suggests that even if the UK's existing nuclear capacity was doubled, it would only provide an 8% cut on CO2 emissions by 2035 (and nothing before 2010).
While the SDC recognised that nuclear is a low carbon technology, with an impressive safety record in the UK, it identifies five major disadvantages:
- No long-term solutions for the storage of nuclear waste are yet available, says the SDC, and storage presents clear safety issues
- The economics of nuclear new-build are highly uncertain, according to the report
- Nuclear would lock the UK into a centralised energy distribution system for the next 50 years when more flexible distribution options are becoming available
- The report claims that nuclear would undermine the drive for greater energy efficiency
- If the UK brings forward a new nuclear programme, it becomes more difficult to deny other countries the same technology, the SDC claims
The panel does not rule out further research into new nuclear technologies and pursuing answers to the waste problem, as future technological developments may justify a re-examination of the issue.
But the report concludes that Britain can meet its energy needs without nuclear power.
"With a combination of a low carbon innovation strategy and an aggressive expansion of energy efficiency and renewables, the UK would become a leader in low carbon technologies," the SDC claims.
Critics of the government's energy review say it is a way to get nuclear power, touted as a possible solution by Tony Blair, back on the agenda.
Conservative energy spokesman Alan Duncan said ministers should pay attention to the commission's conclusions.
"This report puts a spanner in the works for the government, who everybody believes has already made up its mind in favour of nuclear."
The Tories are currently reviewing their energy policy. Zac Goldsmith, deputy chair of the party's environment policy review which is due to report in 18 months' time, is strongly opposed to nuclear power.
The Liberal Democrats have also attacked the economic uncertainties of nuclear power.
The Green Party says the government is determined to push ahead with nuclear power despite evidence that it is uneconomic.
The government is set to publish the findings from the energy review later this year.