Conservative leader David Cameron has warned against retreating to protectionist policies at a time of global financial uncertainty.
Mr Cameron said protectionism offered "false hopes"
He told the World Economic Forum in Davos it would be wrong to respond by putting up trade barriers.
In a speech Mr Cameron said there were signs of protectionist "tendencies in China and India, as well as among US presidential hopefuls".
Instead politicians should champion free trade, he said.
Mr Cameron said the US presidential race had seen candidates on both sides advocate protectionist policies.
But he singled out Republican candidate John McCain for praise, for being prepared to argue that protectionism would not bring back lost industrial jobs - even if it cost him votes.
"As politicians, our actions must match our rhetoric. No buying off domestic opinion with subsidies and barriers.
"At a time of global and economic uncertainty and of financial instability we must not pander to people's fears by peddling false hopes of protectionism," he said.
"In years to come, the world will look back at this period, and there will be heroes and there will be villains.
"The heroes will be those who held their nerve and stood up for free trade.
"The villains will be those who tried to push us over this tipping point and down the dangerous path of protectionism."