Sudan is in the midst of a humanitarian crisis

Gordon Brown pledged a total of �1.5bn to fight the "scourge" of HIV/Aids in the developing world.

Some �150m was also being set aside to help with the crisis in Sudan, he said.

But aid agencies are disappointed Mr Brown failed to pledge to boost overseas aid to the UN target of 0.7% of gross national income by 2008.

Instead this target will be met, if spending levels are sustained the chancellor said, five years later in 2013.

But Mr Brown said the target could be met by 2008/9 if a British finance plan is adopted internationally.

As things stand, this new money will do little for the world's poor Mark Curtis World Development Movement

The Catholic development agency, Cafod, argues more lives will be lost in the developing world.

It claims that for every year the UK fails to meet this target, 250,000 children's lives are lost in the neediest parts of the world.

Cafod's head of public policy George Gelber said: "The increase in aid, though substantial, is a long way short of the �7.9 billion - 0.7% of national income - that Cafod and other development agencies have been campaigning for.

"We would like to have seen a timetable to achieve the UN target firmly spelt out, rather than the mere prediction that the UK is now on course to reach it by 2013."

Finance plan

Cafod supporters were among more than 15,000 campaigners who wrote or e-mailed the chancellor calling on him to meet the UN target - a promise made by the British government in 1970.

The director of pressure group World Development Movement, Mark Curtis, said: "As things stand this new money will do little for the world's poor."

Mr Curtis added: "We can only welcome an increase in aid if accompanied by a commitment from Gordon Brown to stop using the aid budget to force poor countries to adopt free-market policies that have been shown to increase poverty."