Environmental groups have pulled out of a consultation on whether the UK should build nuclear power stations, saying it is not a "fair and full debate".
The government is in favour of more nuclear power stations
Greenpeace and Friends of the Earth are among those unhappy with the way the government has presented the arguments.
They had already won a High Court ruling that a previous consultation was "seriously flawed" and "misleading".
Business and Enterprise Secretary John Hutton said he would be "extremely disappointed" if the groups pulled out.
Public meetings are being held across the UK on Saturday, on the principle of including nuclear power as part of Britain's energy mix, but a coalition of groups has withdrawn its support.
Most existing nuclear power stations are due to close by 2023 and the government has said its "preliminary view" is that new stations should be built - to reduce carbon emissions and Britain's reliance on foreign oil and gas imports.
Environmental groups say that the consultation, rather than presenting a "fair and full public debate", was more about promoting nuclear power.
John Sauven, from Greenpeace, told BBC News: "It is up to the government to decide, is it going to carry out a proper public consultation or not?
"Their own advisers have told them that this consultation should last for nine months, it should put all the information before the public, and they have been very critical of the way it is currently being carried out."
The environmental organisations have formed a coalition, and branded the consultation process a "public relations stitch-up".
Friends of the Earth said it would not be sending representatives to the meetings, and that it would make its case officially to the government.
Earlier this year Greenpeace successfully challenged a previous consultation on the issue at the High Court arguing it had been "a sham".
The judge granted a quashing order and the government began the new consultation.
Mr Hutton said the government had made a preliminary view about the nuclear issue but did not have a "closed mind".
"It is possible that the government might change its view," he said, but told the BBC it would take a "very, very strong" argument to persuade them to reduce the "nuclear element in the energy mix".
A spokesman for his department later said time was "pressing" as most power stations were due to close within decades.
He added: "John Hutton is clear that whatever decision the government finally makes, it is absolutely in the national interest that we make a decision and urgently - our livelihoods and the future health of the planet depend on us getting this right.
"That is why he thinks it is so regrettable that Greenpeace's tactics seem to be to do everything they possibly can do to delay and undermine the process of consultation that they themselves demanded.''
But Liberal Democrat leader Sir Menzies Campbell said he understood concerns about the "deeply flawed consultation".
"The government has failed to observe the spirit of the High Court ruling, by making up its mind on nuclear power long before this latest consultation had even begun," he said.
The government's Energy White Paper on the future of power supplies in the UK also backs renewable energy and efficiency measures.