A leading US climate scientist is considering legal action after he says he was duped into appearing in a Channel 4 documentary that claimed man-made global warming is a myth. Carl Wunsch, professor of physical oceanography at the Massachusetts Institute of Technology, said the film, The Great Global Warming Swindle, was 'grossly distorted' and 'as close to pure propaganda as anything since World War Two'.

He says his comments in the film were taken out of context and that he would not have agreed to take part if he had known it would argue that man-made global warming was not a serious threat. 'I thought they were trying to educate the public about the complexities of climate change,' he said. 'This seems like a deliberate attempt to exploit someone who is on the other side of the issue.' He is considering a complaint to Ofcom, the broadcast regulator.

The film, shown on Thursday, was made by Martin Durkin. In 1997, he produced a similar series for Channel 4 called Against Nature, which attacked many of the claims of the environmental movement.

Durkin said: 'Carl Wunsch was most certainly not "duped" into appearing in the film, as is perfectly clear from our correspondence with him. Nor are his comments taken out of context. His interview, as used in the programme, perfectly accurately represents what he said.'

Channel 4 said: 'We feel it is important that all sides of the debate are aired. If one of the scientists featured now has concerns about his contribution, we will look into it in the normal way.'