Michael Hintze, a leading Conservative party donor who runs the £5bn hedge fund CQS, has emerged as a financial backer of the climate sceptic thinktank founded by former chancellor, Lord Nigel Lawson.

The Global Warming Policy Foundation, launched by Lawson in 2009, regularly casts doubt on the science and cost of tackling climate change in the media and has called on climate scientists to show greater transparency, but has refused to reveal details of its donors. Leading Nasa climate scientist James Hansen calls it "one link in a devious manipulation of public opinion [regarding climate change]."

On Monday, Downing Street was forced to reveal that Hintze was among the leading Tory donors who were invited to privately dine with David Cameron at a "thank you" dinner following the general election in 2010. The revelation that Hintze, who has also donated £1.5m to the Tory party, is connected with climate change scepticism will be an embarassment for David Cameron, who has pledged to lead the "greenest government ever".