Chancellor Gordon Brown has accused EU countries of hypocrisy for refusing to reform the Common Agricultural Policy.
Gordon Brown wants African farmers to trade on a fairer basis
A week before the G8 Gleneagles summit on poverty and climate change he said it was time to ditch farm subsidies and allow the developing world to compete.
That would allow the poorer nations to trade their way out of their plight.
"We cannot any longer ignore what people in the poorest countries will see as our hypocrisy of developed country protectionism," he said.
"We should be opening our markets and removing trade-distorting subsidies and in particular, doing more to urgently tackle the waste of the common agricultural policy by now setting a date for the end of export subsidies."
UK Prime Minister Tony Blair is at loggerheads with France's President Jacques Chirac because Britain will only consider reform of its £3bn EU rebate if the CAP is put on the negotiating table.
With French farms benefitting from generous farm subsidies Mr Chirac is not prepared to countenance CAP reform.
Speaking in London to the UN children's agency Unicef Mr Brown said: "Unfair trade rules do not only prevent poor people from throwing off the shackles of poverty, but shackle poor people and poor communities still further.
"And so trade justice is not simply about removing the barriers that hurt the poor, but about creating new capacity that empowers poor countries to participate on equal terms in the new economy."
Mr Brown gave examples of African producers who were losing out because of the CAP.
"Think of the Mozambican sugar producer who cannot compete with European sugar beet farmers, because the subsidies Europeans receive enable them to sell more expensive goods at a cheaper price," he said.
"Or think of the Ghanaian coca growers who cannot process their beans for chocolate themselves, because tariffs mean its cheaper to process them in Europe - in fact while developing countries produce 90% of the world's cocoa beans, it is developed countries that produce 90% of the world's chocolate."
Despite the obstacles there is a feeling of progress over Africa.
Beyond the writing off of debt there is now a deal in place on aid, including new money from Italy and Germany which fulfils the demand of Mr Blair's Africa Commission, to increase aid to Africa by another $25bn a year by 2010.
The help should provide secure, predictable, long-term aid to pay for education and health care - the twin pillars of development - as well as new infrastructure like roads and ports.