The Cabinet is split over whether to approve a controversial plan for a £1bn coal-fired power station at Kingsnorth in Kent which has become a key test of its green credentials.
John Hutton, the Business Secretary, wants to approve the project even if it is not chosen for an experiment in which its carbon emissions would be "captured" and stored under the sea.
But his position is strongly opposed by Hilary Benn, the Environment Secretary, and his predecessor David Miliband, now the Foreign Secretary. They believe the plant should not be built unless it can test commercial-scale carbon capture.
The Government's decision on whether to approve E.ON UK's application to build the plant is due shortly, but ministers will not know whether Kingsnorth will be chosen for a carbon capture experiment for another nine months. Ministers opposing Mr Hutton want to postpone a decision until then. "He is trying to bounce the Prime Minister into a change of government policy," a minister in another department said.
Mr Hutton's allies denied the charge, saying that emissions from Kingsnorth would be lower than existing coal-fired stations and would not increase pollution because Britain's emissions are capped under the EU's emissions trading scheme.
Downing Street believes the Business Secretary stepped over the line in his speech to Labour's annual conference this week. Arguing that greater use of coal was needed to keep the lights on and diversify Britain's energy supplies, he said: "Stopping the building of new coal-fired power stations would make no difference to the UK's total carbon emissions but it would, I believe, damage our energy security." Gordon Brown was more cautious in his conference speech, calling for "investment in clean coal". His aides said this was the Government's official policy. The Prime Minister has not yet decided whether to back Mr Hutton or his opponents when the issue is discussed by the Cabinet.
Kingsnorth has become a cause célèbre for environmental groups.
John Sauven, executive director of Greenpeace, said: "John Hutton is trying to box Gordon Brown into a corner on new coal-fired power stations. It's become clear to everyone except Hutton that we can't build new coal-fired power stations and still deal with climate change. And nor do we have to in order to 'keep the lights on'. Numerous studies show that a mixture of renewable energy, energy efficiency and using fossil fuels more efficiently in combined heat and power plants will more than meet our needs. Brown needs to stop dithering and clearly say no to new unabated coal."
Explainer: The coal threat
Burning coal produces almost twice as much CO2 per unit of heat energy generated as natural gas, with oil in between. James Hansen, the US climate scientist, says coal poses the gravest threat of climate change.
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