Tony Blair has said he is still firmly behind the construction of new nuclear power stations, despite losing a High Court battle with Greenpeace.
Mr Blair says nuclear power is needed to cut carbon emissions
The court found the decision to back a new generation of power stations was unlawful, because of a "seriously flawed" public consultation process.
Ministers plan to re-consult, but say nuclear power is the best way to tackle climate change and energy security.
Mr Blair told the BBC: "This won't affect the policy at all".
'Bad for business'
He said it was important to have nuclear power "back on the agenda".
"If we don't replace the existing nuclear power stations then, first, I cannot see how we are going to meet our climate change targets.
"And secondly we... will move to a situation that without nuclear power we are going to be dependent on very uncertain supplies of energy and that would be bad for business and bad for the consumer."
Greenpeace brought the case after accusing the government of reneging on its promise to carry out "the fullest consultation" before deciding about whether to build new power stations.
In 2003 the government had described nuclear power as an "unattractive option".
But by July 2006 its report The Energy Challenge, said "new nuclear power stations would make a significant contribution to meeting our energy policy goals".
Greenpeace argued, and the judge agreed, that the consultation in 2006 did not give enough information about radioactive waste disposal and the costs involved.
And he said the information given to Greenpeace and other consultees was "wholly insufficient for them to make an intelligent response".
Mr Justice Sullivan said "something has gone clearly and radically wrong".
"There was therefore procedural unfairness and a breach of Greenpeace's legitimate expectation that there would be the fullest consultation before a decision was taken," he said.
The decision means the government has to pause in its plans for a new generation of nuclear power stations, as it will now have to hold another consultation process.
Greenpeace spokeswoman Emma Gibson told the BBC the consultation had been a "sham".
"If Tony Blair wants to continue with his misguided plan for a whole new generation of nuclear power stations, the government will have to go back to the drawing board," she said.
Green Party spokeswoman Sian Berry also said the Energy Review had merely been a "rubber-stamping exercise".
Shadow trade and industry secretary Alan Duncan desribed it as "an astonishing ruling" which showed up the government as "fundamentally deceitful."
Liberal Democrat environment spokesman Chris Huhne said: "The judgement really shows you can't perform a 180-degree U-turn on a matter as important as nuclear power without a proper public debate.
"It's a real slap in the face for the prime minister's sofa style of government."
The government says its proposals, including building more nuclear plants, will cut carbon emissions by 19 to 25 million tonnes by 2020, compared with projections based on current trends.
Mr Blair announced in January that a white paper would be published next month. It is not yet clear whether the court ruling will lead to a rethink on timing.