A chorus of national leaders, business executives and heads of international organisations have warned of a slide towards protectionism if nothing is done to kick new life into the stalled Doha trade negotiations.

The sticking points in the trade talks remain as deep as ever but the Group of 20 is, nevertheless, set to agree on Friday a new deadline of 2011 for completion of the talks, arguing there is a window of opportunity before the US presidential election campaign started in earnest in 2012.

“We’re going to fight protectionism in all its forms,” said David Cameron, UK prime minister, adding that the Doha trade negotiations had “got to be something we achieve next year, 2011. It’s an international embarrassment that we haven’t completed this trade round”.