Charities said the emergence of a group of poor countries acting as a bloc to press their interests against the mighty EU and United States was a good sign.

But they lamented the lost opportunity to start unwinding the massive subsidies rich countries pay to their farmers, which poor countries say keep them poor.

"Rich countries overplayed their hand and misjudged the strength of feeling and unity of the developing world, who want to make trade fair and have a stake in global prosperity," aid group Oxfam said in a statement.

"Oxfam takes no delight in this failure. It is a missed opportunity."

Britain's Catholic Fund for Overseas Development, Cafod, singled out "arrogant and disdainful" EU negotiators for pressing ahead with discussion of issues that poor countries wanted shelved, while refusing to yield on farm subsidies.

"On agriculture - the litmus test of rich countries' commitment to development - the conference was heading toward a deal that would have offered only crumbs to developing countries, especially the poorest of them.

"The EU must grapple with its morally repugnant and economically crazy Common Agricultural Policy."

Charlie Kronick, chief policy adviser on trade issues for environmental group Greenpeace said Cancun proved that the entire international trade system needed to be rethought, with greater attention to the needs of the poor and the environment.

"The bottom line is that no deal is much better than a very bad deal," he said.