It is now six weeks since I launched an investigation, with my colleague Richard North, into the affairs of Dr Rajendra Pachauri, chairman of the UN's Intergovernmental Panel on Climate Change (IPCC), the hugely influential body which for 20 years has been the central driver of worldwide alarm about global warming. Since then the story has grown almost daily, leading to worldwide calls for Dr Pachauri's resignation. But increasingly this has also widened out to question the authority of the IPCC itself. Contrary to the tendentious claim that its reports represent a "consensus of the world's top 2,500 climate scientists" (most of its contributors are not climate experts at all), it has now emerged, for instance, that one of the more widely quoted scare stories from its 2007 report was drawn from the work of a British "green activist" who occasionally writes as a freelance for The Guardian and The Independent.