THE White House is pressing for next month's G8 summit in Gleneagles to make a clear statement of support for nuclear power, opening up a new rift with the UK over climate change.
The US pressure over nuclear power is revealed in a confidential paper prepared by UK government officials as part of the preparatory talks before the Gleneagles meeting.
The leaked document, entitled Powering a cleaner future, discloses that the UK considers rejecting the US position to be a "red line" issue, on which no concessions can be made.
However, the UK is willing to see the summit endorse a US project for a new worldwide generation of nuclear reactors.
Tony Blair hopes the summit will produce a new "action plan" on reducing carbon dioxide emissions, but disputes over the role of nuclear power in that strategy could yet undermine his plans.
George Bush, the US president, has suggested nuclear power could be a "clean" power source for the future, angering environmentalists.
US officials have been arguing that the Gleneagles action plan should contain a section dedicated to advocating atomic power. That, the paper makes clear, is unacceptable to Margaret Beckett, the Environment Secretary and a known sceptic about nuclear power.
"UK red line: Avoid US suggestion for a separate 'nuclear' heading," the document says.
Instead of committing the G8 countries to greater use of nuclear power, Britain wants a final summit declaration that "leaves it up to individuals to decide whether nuclear is a suitable part of their energy mix".
Still, the paper reveals that the UK is ready to accept a G8 statement giving apparent support to the US-backed "Generation IV" plan.
Generation IV is a long-term study which the US department of energy describes as an international attempt to "broaden the opportunities for the use of nuclear energy".
According to the Generation IV analysis, nuclear reactors are "generating electricity in a reliable, environmentally safe and affordable manner without emitting noxious gases into the atmosphere".
Britain's current generation of nuclear reactors is nearing the end of its useful life, meaning the government will shortly have to take a decision about whether to build another.
The Prime Minister's scientific advisers are known to see new reactors as the only way for Britain to meet targets for cutting greenhouse emissions.
By contrast, ministers led by Mrs Beckett have grave doubts.
Speaking in Russia, Mr Blair yesterday said there was "a real prospect of progress" on climate change in Gleneagles, but he added: "There's obviously still a lot of hard negotiating to do."
Mr Blair has so far won cautious support from green groups over his drive for a climate change accord, but any move by the G8 to back nuclear power could cost the Prime Minister that backing.
Meanwhile, Robin Cook, the former foreign secretary, yesterday increased the pressure on Mr Blair to broker a meaningful climate deal at Gleneagles. That, Mr Cook said, was at least as important as an agreement on African poverty.