The statement could put pressure on the US and EU, whom critics say have been intransigent on the needs of developing economies.

'This bonding is driven by the desire not to preside any more over the perpetuation of inequalities in global trade,' said Indian trade minister Kamal Nath. 'This will continue to happen unless we present a united front.'

It was widely expected that the developing countries would, at some stage, up the ante after so little progress had been made in the first three days of negotiations, aside from a draft text to grant duty-free access to imports from least developing countries.

But countries from the component groupings, including G-20, G33, the African group, the Least Developed Countries and the so-called Small Economies appear to have been forced to compromise on, or at least put aside, a number of divisive issues in an attempt to extract serious offers from developed nations on market access and elimination of subsidies.

'All too often a round for free for the [least developed countries] discussed by rich nations in plenary speeches becomes a round for free for themselves in the green room,' Mr Nath complained. 'What amazes me is that what the European Union and the United States are demanding is that we pay them to stop doing what they shouldn't be doing anyway, which is distorting global trade.'

Earlier in the day, the anger felt by developing nations about the direction of the talks so far was palpable at a conference of ministers from the African, Caribbean and Pacific group (ACP) to protest at US intransigence on cotton subsidies and the erosion of preferential treatment for exports of banana and sugar to the EU.

Arvin Boolell, minister for agriculture of Mauritius, complained of negotiating tactics designed to drive a wedge between smaller nations.

'As the talks unfold, we are being marginalised and our legitimate concerns set to one side,' he said. 'We should not be written off and we are appealing to everyone who will listen that our people have the right to live.'

But with ACP countries later being included among the 110-strong coalition of developing nations, it is difficult to believe that heavyweights like the EU will not seek to create divisions from the many hot-button issues that divide them. For instance, ACP countries such as Mauritius and Dominica are worried about the impact of a loss of preferential access to European markets for agricultural products once these markets are opened to all least developed countries.

Understandably, the developing nations, led by Brazil and India, sought to play down any differences. Their statement merely recognised 'the need to address the concerns of preference-receiving countries'.

At the very least, however, the developing nations scored a public relations victory over the US, the EU and other rich economies. Representatives of the world's poorest countries linking arms on stage with former UN commissioner for human rights Mary Robinson is not an image Peter Mandelson and Rob Portman will find easy to counter.

Likewise the crux of the developing countries' argument.

On the issue of tariff-free market access, Dipak Patel, chief negotiator for the 49 least developed countries, said: 'A lot of the developed countries tell us they have domestic problems in granting access. But I find it inconceivable that people in some of the richest countries in the world would demonstrate in the streets against the idea of granting market access to the poorest countries on the planet. This is a political problem, not a domestic one.