Al Gore savaged the US government’s “obstructing” attitude and urged delegates at the UN conference on climate change to ignore Washington if necessary to pursue the “moral imperative” of a new global regime.

“My country is principally responsible for obstructing progress here in Bali,” the former US vice-president told 2,000 of the 12,000 people attending the conference on Thursday. “[But] over the next two years the United States is going to be somewhere it is not now.”