"We certainly do not need extra nuclear power in anything like a 10- or 15-year cycle," Beckett told ITV television on Sunday.

"We have not shut the door on nuclear power. We have said that as we get to the stage where we have used up the options that we can now see, we will have to reassess where we are."

Britain relies on nuclear power for around a quarter of its electricity generation, but has not built any new plants for over a decade and most of its reactors are scheduled to close over the next 20 years.

Prime Minister Tony Blair has in the past said he will not rule out another generation of nuclear power stations, but his government is more eager to concentrate on renewable energy sources to cut carbon emissions.

While nuclear power plants do not produce carbon dioxide emissions, Beckett said their value as sustainable energy sources was limited because of the difficult and lengthy decommissioning process.

"It is really hard to argue - when sustainable development means not leaving legacies for future generations to deal with - that nuclear power is a sustainable form of energy use," Beckett said.

Asked when the government was likely to make a definitive decision on whether nuclear power capacity should be increased, Beckett said: "We certainly don't see any need to come to a view on that probably in the run up to, say, 2015 or 2020."

The government has promised that 10 percent of the country's electricity will come from green sources by 2010, of which between 7 and 8 percent will come from wind power.