'Coal is so clean and fresh that the prime minister brushes his teeth with it, Downing Street said last night. Mr Brown said advances in coal technology meant it was now one of the cleanest substances on Earth, and an unrivalled remover of stains and scaling." So says the satirical website the Daily Mash. The real claims are scarcely battier.

Ministers are about to decide whether to approve a new coal-burning power station at Kingsnorth in Kent. This would be the first such plant to be built in Britain since the monster at Drax was finished in 1986. As well as coal, it will burn up the government's targets, policies and promises on climate change.

John Hutton, the secretary of state in charge of energy, has started justifying the decision he says he hasn't made. "For critics," he argued last week, "there's a belief that coal-fired power stations undermine the UK's leadership position on climate change. In fact, the opposite is true." Quite so: if we don't burn this stuff the Chinese might get their hands on it. Or could he be a true believer? Does he really think there's such a thing as clean coal?

Clean coal's definition changes according to whom the industry is lobbying. Sometimes it means more efficient power stations - which still produce almost twice as much carbon dioxide as gas plants. Sometimes it means removing sulphur dioxide from the smoke, which boosts the CO2. Sometimes it means carbon capture and storage: stripping the carbon out of the exhaust gases, piping it away and burying it in geological formations. None of these equate to clean coal, as you will see if you visit an opencast mine. But they create a marvellous amount of confusion in the public mind, which gives the government a chance to excuse the inexcusable.

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