In less time and with less money than it takes to build new nuclear reactors, or try out ways of burying emissions from dirty power plants, the government could hit its energy goals by using proven technology available now.

"We are much better off focusing on the things that we know will work and deliver results fast," Oakley told Reuters.

"The key ones are efficiency, going after decentralised energy to make the system more efficient, and bringing on renewables as quickly as possible," he said in an interview. Government ministers previously opposed to atomic energy, including Trade and Industry Secretary Alistair Darling, have warmed to it as the threat of climate change has grown, arguing that it offers clean power and cuts reliance on imported gas.

Apart from safety and waste disposal concerns, Greenpeace argues that nuclear is expensive, impractical and slow to offer a solution to either problem.

"It's a technology that only generates electricity at a time when we need to be reducing emissions and dealing with energy questions right across the board including heat and transport," Oakley said.

Instead, Britain should be cutting energy use while building lots of small combined heat and power (CHP) plants that are more energy efficient because they pipe the heat given off from electricity production to homes and businesses.

"You get a more secure electricity supply if you have got a more diverse range of sources, as you woulds have under a decentralised energy system," Oakley said.

CHPs can burn various fuels from organic matter to coal or gas. And as they can be up to 95 percent efficient, whatever they burn means less emissions per unit of energy produced.

"They deliver immediate results, they are cheaper to deploy and they give you a much bigger impact on reducing gas use and reducing emissions than nuclear power, which can't be delivered within the next decade," Oakley said.

Oakley cited government figures showing the UK could build enough CHP plants to produce about twice the electricity that the nuclear industry does today, about 20 percent, in less time than it would take to replace its existing nuclear plants.

Backed up by wind, wave and tidal power, CHPs and energy efficiency can make nuclear power irrelevant, he added.

ENERGY EFFICIENCY

According to Greenpeace, the government's own figures show that energy use across all sectors could be cut by 30 percent, saving more money than would need to be spent on the changes.

Simply banning incandescent light bulbs would slash demand by more than the output of a large nuclear power station.

"At the moment our power stations lose about two thirds of their energy, so there is enormous inefficiency in the supply side system," Oakley said.

"Clearly that impact alone would be far greater than a new fleet, or even doubling the size of our current reactor fleet."

Darling said when he presented the government's latest energy policy on Wednesday that efficiency would be a priority.

But analysts and environmental groups have voiced scepticism about any real results emerging from its latest policy review.

"They have had a priority, in theory, of energy efficiency for four years now...The 2003 white paper identified energy efficiency as the cheapest and most effective," Oakley said.

"They said that was a priority and did nothing about it."

BAD EXAMPLE

Because Britain has claimed a leading role in fighting climate change, mistakes that it makes could be followed by other rich countries while poorer nations could be left without examples of practical low-carbon energy models, Oakley argued.