The anti-poverty campaigner said some good work was coming out of the conference but added that rich nations were falling well short on commitments made three years ago at Gleneagles.

His comments came as Gordon Brown prepared for crunch talks with fellow world leaders in a bid to secure support for his plans to boost aid to Africa and curb soaring oil prices.

A fresh commitment to meet previous aid pledges and radical plans to end petrol dependency are top of the UK's agenda at the G8 summit - Mr Brown's first as Prime Minister.

Intense discussions between the leading industrialised nations will focus on the poor state of the world economy - including the impact of soaring oil and food prices.

The Prime Minister wants them to use the opportunity to reaffirm a commitment made at the 2005 Gleneagles summit to double international aid, notably to Africa, by 2010.

But Geldof indicated that leading industrialised countries were already off target with regard to their pledge.

In an interview with the BBC, he said: "This is the halfway point to 2010, which is when the Gleneagles promise comes up, and they should be 50% of the way there but in fact they are 14% of the way there."

As to the current summit, Geldof said things were progressing in a "G8-ish" way. He added: "Some stuff has come out - there has been some good stuff. The Europeans have come up with one billion dollars for the food crisis, for agriculture - that is a good response. There is also talk of an aggravated 10 billion to deal with this as well.

"There is also talk of another billion for education. Whether we see that or not, who knows? But at least the talk is positive enough."