He then punched the air while grinning widely, as the rest of those present, including British Prime Minister Gordon Brown and French President Nicolas Sarkozy, looked on in shock, reported The Telegraph newspaper yesterday.

Mr Bush, whose second and final term ends this year, then left the meeting at the Windsor Hotel in Hokkaido, Japan, where the leaders of the world's richest nations had been discussing new targets to cut carbon emissions.

'Everyone was very surprised that he was making a joke about the US' record on pollution,' the newspaper quoted an official who had witnessed the extraordinary scene as saying afterwards.

It was a defiant farewell from the President over his refusal to accept global climate change targets, said the Independent newspaper.

Mr Bush had given some ground at the summit by saying he would 'seriously consider' a 50per cent cut in carbon emissions by the year 2050.