British Prime Minister Tony Blair announced Tuesday a sweeping review of the country's energy needs that will specifically look into the option of building new nuclear power stations.

Blair – who is reportedly in favour of resurrecting Britain's nuclear energy programme – gave his strongest hint yet that a combination of nuclear and renewable sources such as wind power could be the way forward.

His speech, however, was delayed for about an hour after two protesters from the environmental campaign group Greenpeace scaled the roof of the auditorium at the central London venue.

The pair, wearing smart suits, got through tight conference security with legitimate passes but for a fictitious company, organisers said.

In a widely-trailed announcement, Blair told the Confederation of British Industry's annual conference the review would look into Britain's progress against the medium- and long-term energy goals and report by mid-2006.

"It will include specifically the issue of whether we facilitate the development of a new generation of nuclear power stations," Blair stated.

Greenpeace protesters, holding banners and dropping tickertape stating "Nuclear: Wrong Answer", refused to come down from their perch in the rafters ahead of Blair's speech.

Digby Jones, the CBI's director general, told delegates that the pair — supported by others outside, some wearing radiation suits and gas masks — would not be granted their request to be allowed to make a 10-minute speech.

The venue for Blair's speech was hastily switched to a cramped antechamber after the protesters were also refused an opportunity to ask Blair questions.

"The CBI will not be held to ransom or bow to ultimatums," Jones said afterwards.

"The democractically-elected leader of this nation has every right to speak, and I applaud him, and our delegates, for the determined response which ensured the speech was delivered."

The duo were later arrested for aggravated trespass, the Metropolitan Police said. Greenpeace described the protest as the start of the "fightback against a new nuclear era in the UK".

Undeterred by the disruption, but calling for his opponents to engage in a "serious, open and democratic debate", Blair said action on energy supply was needed because of rising prices, dwindling supplies and climate change.

He told his audience that like many countries, Britain needed to diversify out of dependence on one source of energy as the country's existing coal and nuclear plants neared decommissioning.

"Some of this will be replaced by renewables, but not all of it can," he added.

Energy Minister Malcolm Wicks said later the aim of the review, which he will lead, will be to ensure "clean, reliable, affordable energy supplies for the long term".

As well as nuclear power, it will look at coal, gas and new technologies plus transport and the role of energy efficiency, he added, also indicating a possible nuclear-renewable combination.

"There is no single solution. It is certainly not a case of nuclear versus renewables," he told reporters.

A switch to nuclear would be a major policy shift for Blair and likely to provoke strong reaction from environmentalists but also within his governing Labour Party.

Britain has about a dozen nuclear power stations, most of them built in the 1960s and 1970s, providing about 25 percent of the country's electricity, compared with natural gas which provides about 40 percent.

Proponents of new reactors — which emit virtually no carbon dioxide — argue they would help Britain meet its pledge to reduce greenhouse gas emissions by 20 percent of 1990 levels by 2010.

Opponents highlight a number of issues, particularly the unresolved problem of nuclear waste.

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