It is 20 years since Bob Geldof was shocked by footage of famine in Ethiopia and rallied the cream of the pop world to play at Live Aid. Now he’s doing it again. But this time it won’t be for the Band Aid plaster of relief supplies. This time it includes U2, Paul McCartney, the Rolling Stones and Joss Stone at a Live 8 concert in Hyde Park on July 2 and a mass rally at the G8 summit next month. And the aim will be to goad politicians from the eight wealthiest nations into ending unfair policies that make it impossible for Africa’s poorest to break out of poverty.

“War, hunger, Aids: they are simply visible excresences of a singular condition and this is being poor,” Geldof says, leaning over the table at his office in St James’s Square, his unruly hair dangling in front of his eyes. “It seems laughable in the globalised world which is supposed to benefit everybody.”

Geldof is leading a new crusade that will reach a climax at the G8 in July, because he believes it is not merely the lack of aid that is keeping Africa poor. At the root of the problem, he says, are the unfair terms of trade and the amount that sub-Saharan Africa pays in interest to rich countries.

“Most Africans are born into debt slavery and will die owing greater amounts of money.” In return for loans, African countries are being forced to abandon protective measures for their own farmers, but they still face a wall of protectionist subsidies and restrictions when they try to sell their goods in the rich countries that lent them money. They are caught in a rat trap and the leaders who can do most to free them from these economic shackles are the eight meeting at Gleneagles.

“Twenty years ago there was an issue of famine for me,” says Geldof. “I mean potentially 30 million people dying of hunger in a world of surplus seemed intellectually absurd and morally repulsive. So I tried to do something and stumbled unwittingly into the fact that it was a political issue: 400 years ago, Africa and Europe were equal; 100 years ago, the discrepancy in income was six to one; today it is 100 to one. Why?”

That is the question that the Commission for Africa sought to answer. It was set up by Tony Blair last year with Geldof, Gordon Brown and many African politicians. “It’s main finding is governance - well did you need a Commission for Africa to tell you that?” he asks. The problem, he says, is the lack of government structures or accountability, and endemic corruption. Without functioning government, an African state cannot collect taxes. Hospitals, roads and schools can’t be built. So there isn’t a healthy population to produce more goods and help it trade its way out of poverty.

“If the state gives no benefits or assistance, why pay loyalty to the state? They don’t. They owe loyalty to their ancient structures, their clans, their tribes, their ethnic groups, or to the new politics of religion: Islam in the north or evangelical Christianity in the south.”

That can be a recipe for conflict. So what can the G8 do about it? “The commission says essentially that unless we deal with governance, nothing else follows.”

But it has also demanded that rich countries pay more and better aid, wipe the slate clean on debt, and stop handicapping African farmers by subsidising their own.

“The UK has accepted, bravely in my opinion, a radical agenda. It far out- radicalises what the aid charities expected and it calls for an immediate doubling and, potentially, by 2010, a trebling of aid. That is the UK’s policy going forwards into the G8. It’s very fucking important.”

The lean former Boomtown Rats singer is a much warmer character than his trademark scowls on TV suggest. But he is not afraid of world statesmen - he famously challenged Margaret Thatcher over Europe’s butter mountains.

Now he accuses G8 leaders of bickering over how to bankroll debt relief.

“I ask you!” he exclaims, throwing up his hands. “If they’ve won the argument to the point where they have already eliminated a third of the debt and seen the benefits to countries like Uganda (which has declared free primary education), why don’t they just do it? I mean more people die of hunger than war, Aids, TB, malaria and polio combined. It’s unbelievable in this world of surplus that 98 per cent of children in Africa will go to bed tonight feeling hungry. The agreement through the Heavily Indebted Poor Countries’ initiative is that if we alleviate debt it will go into primary farming. So we don’t care how you do it: just get on with it, guys.”

Geldof - dubbed Saint Bob, knighted, and nominated three times for a Nobel peace prize - swears he is not an idealist.

“I am utterly a pragmatist. It drives me nuts because I can see clearly and understand the arguments by Jeoff Sachs (an adviser on economic reform) and Amartya Sen (the Nobel prize-winning economist) that there is a body of opinion which says this is bollocks and you can stop it. This G8 we get to stop it.”

Last year Geldof complained that he was sick of politicans’ fine words not being matched by deeds. So does he believe they will deliver this time?

“Not unless we do everything in our power to force them to do it. We have to create lobbies that build that heat,” he says.

And that is where teachers come in.

Geldof says he was “crap at school, didn’t have a single exam in my life”, but he knows the value of a good teacher. English teachers introduced him to poetry, which inspired him to write lyrics. (He carries a copy of Milton’s Paradise Lost around to this day.) He wants every teacher to get hold of the children’s version in blue of the Commission for Africa report, and use its declaration to inspire a generation to fight for a just world.

“It’s very Jeffersonian,” he says of the declaration. “It says we find the conditions of Africans to be intolerable and calls for an alteration of policy in favour of the weak. ”

He wants teachers to inspire pupils to learn more about Africa: “It’s unbelievably beautiful and luminous and dynamic. Show me someone who isn’t into all those stories about the jungles and the forests and the deserts. I mean they have more languages than any other continent, 2,000 separate peoples with wholly different legends, myths and history. And that all plugs in. Informs us.”

He calls for twinning between schools, a to-ing and fro-ing of ideas. He supports the Send My Friend To School campaign which fights for the 100 million worldwide denied education. It is urging supporters to send cardboard cut-outs of the non-pupils to remind the G8 leaders of the problem. Above all, he urges teachers to take direct action.

“I want every school to decamp on July 5. I want teachers to lead them to Edinburgh. I want all the schools with their blazers, their school flags up there, waving that little blue book saying, ‘Do it now, you idiots!’

“It would be an immense little moment of nudge-nudge, wink-wink civil disobedience. What’s more important for those two days: that you learn geometry or that you do something you will remember all your life, that you conceivably helped tip the world a little in favour of the weak, the poor? I know if I was a teacher where I would be going.”

He is fed up being “Mr Bloody Africa”, because he thinks the problem should have been solved. But he looks back fondly on Live Aid as a seminal moment in the social consciousness of the world. He says the heightened awareness of global issues in Britain since then, and the chance confluence of Britain’s presidencies of the G8 and EU this year, offer a unique opportunity.

“Since Live Aid we have followed a journey to the point where we are all talking, where the guys with guitars get to write some of the global public policy. So it’s an immense moment for this country to have this huge political influence and conceivably, with a fair wind, to alter the world for the better.”

For children’s version of the Commission for Africa’s report and classroom posters, visit: www.learningafrica.org.ukwww.sendmyfriend.orgFor the declaration, see www.commissiononafrica.orgEdinburgh rally: makepovertyhistory.org

FROM HELLRAISER TO FUNDRAISER

1951 Born in Dublin

1975 Formed Boomtown Rats, a punknew wave rock band

1984 Launched Band Aid

1985 Live Aid, watched by 1.8bn people worldwide, and ‘Do They Know It’s Christmas’ raise pound;100m

1986 Initiated Sports Aid. Awarded a knighthood

1991 Founded Planet 24, TV production company, famous for The Big Breakfast

1999 Co-founded 10 Alps, a TV, radio and events company

2004 Joined Africa Commission

2001 Helps start DATA, to lobby on debt, Aids and trade in Africa

2005 Given Outstanding Contribution to Music Award at Brit Awards