in a move that could improve the industry's long-term prospects.

It said some of the work could be completed by up to 35 years earlier than had previously been expected.

Government energy policy is focused on boosting supply from renewable sources and increasing energy efficiency, though it has not ruled out a nuclear option.

With Britain's renewable energy targets seen as challenging in some sections of the energy industry, however, and the price of oil and gas having risen sharply, there have been suggestions that

nuclear energy could push its way back on to the agenda.

Yesterday Dipesh Shah, the UKAEA's chief executive, said the lower costs and accelerated timescale of the cleanup "will instill further

confidence in the community that we can clean up the legacy of the past." Asked if the lower costs would make the government more likely to approve nuclear power stations in the future, he told BBC Radio 4's Today: "I think the government is right to keep the options open. The kind of work the UKAEA is doing in clearing up the legacy of the past will be an essential precondition."

UKAEA's responsibilities take in the reactors and other facilities built as part of the nuclear research and development programme in the 40s and 50s, as well as the production of weapons- grade

plutonium, and cover sites such as Dounreay, Harwell and Windscale.

Yesterday it said it was cutting its previous forecast for the cost of the clean-up from pounds 6.3bn to pounds 4.8bn, taking dvantage

of new technologies - including remote-controlled vehicles developed for the offshore oil industry - and the cost-effective treatment of fuels. Much of the saving would be accounted for by Dounreay, where work is now expected to be completed by 2036, rather than 2063, and at a cost of pounds 2.7bn rather than pounds 3.7bn.

Though the industry may hope that cheaper and faster decommissioning of nuclear plants will help change public perceptions, critics say the economics are still firmly against nuclear power.

Greenpeace's Jean McSorley said the idea that the economics of the market for nuclear power would be changed by such factors was "nonsense". Much of the capital cost of new nuclear capacity was incurred at the beginning of the project.

"And what are they going to do with the waste?" she asked. "It does not just disappear."

guardian.co.uk/nuclear