The government has been forced to reconsult on its plans to build a new generation of nuclear plants after a High Court judge in London yesterday decreed an earlier consultation had been flawed.

Greenpeace, the environmental group, succeeded in mounting a legal challenge against the government, claiming it had failed to carry out the fullest public consultation before publishing its conclusions last year.

The organisation complained there had been a failure to present clear proposals and information on key issues, such as disposal of radioactive waste and building costs during the six-month consultation.

The government will not appeal against the decision and will reconsult, but, according to Alistair Darling, Trade and Industry Secretary, it will maintain its support for the nuclear option.

Speaking on the BBC's World at One, he said counter views would be taken into consideration but he said that on a matter as important as climate change it was not possible to stand back and be ambivalent about the country's energy supply.

He pointed out the judge's ruling was on the process of consultation, not the principle of nuclear power.

Sarah North, head of Greenpeace's nuclear campaign, said: "The government's so-called consultation on nuclear power was obviously a sham, and we're pleased that the judge has agreed with us. The government completely failed to consult adequately and even kept relevant documents to themselves. They've now been forced back to the drawing board to conduct a proper and lengthy review.

"Nuclear power is a dangerous distraction from the real solutions to climate change as it only represents 3.6% of our total energy.

"It's entirely obvious that there are more efficient, effective, safer and cheaper ways than nuclear power to meet our energy needs and cut climate change emissions," she added.

The government had argued the energy review was only part of a process which would ensure full consultation but Mr Justice Sullivan found something had gone clearly and radically wrong with the process.

The consultation document, he said, had given every appearance of being simply an issues paper, and he found the information on waste had been not merely inadequate but also misleading. He granted what he called a quashing order.

Alan Duncan, Shadow Trade and Industry Secretary, said: "What it really says is the government has been shown up as fundamentally deceitful."

Chris Hulne, LibDem environment spokesman, said: "The judgment shows you can't perform a 180-degree U-turn on a matter as important as nuclear power without a proper public debate."

Peter Luff, Tory chairman of the Trade and Industry Select Committee, described the decision as a hollow victory.

He said the government had been rushing the consultation to make up for lost time, but insisted nuclear power was still necessary to secure future energy supplies.