The Big Question: Can rock stars change the world?

Do celebrities have the power to effect change?

No, according to our guest editor, Bono. And a lot of people agree with him. Even those people who most want the world changed. Indeed, perhaps especially them.

But didn't Live8 and the Make Poverty History campaign rely on rock star power?

After the leaders of the rich world issued their communiqué at the Gleneagles summit there was a bit of a hoo-haa. Kumi Naidoo, the leader of the Global Call to Action Against Poverty - the international campaign of which Make Poverty History was just the UK end - stood up at the press conference and voiced his disappointment. Some 157 million people had joined that campaign in 75 countries right across the globe. Not to mention the 3.8 billion people - more than half the population of the world - who had tuned in to one of the 10 Live8 concerts at some point. And the 38 million who signed the Live8 petition which Bono and Bob Geldof took into the leaders of the G8 on the eve of Gleneagles. The people have roared, said Kumi and in response the leaders of the rich world had merely whispered.

Geldof was irritated. Of course the G8 had not delivered everything that the poor of the world needed. But they had pledged to double their aid contributions each year globally, half of which was to go to Africa. They wiped away 100 per cent of the multilateral debts the continent owed. They conceded, for the first time, that developing nations should be allowed to integrate with the global market at a pace which suited them and not the rich world. And they endorsed more than 50 of the 980 recommendations of the Commission for Africa on which Geldof had toiled for the past year. Not everything, by any means, but a dramatic step forward. And one which should be praised before moving on to ask for more. Anyone who didn't acknowledge that was an utter disgrace, he added with characteristically unminced language.

In the audience, representatives of some of the more hardline campaign groups shook their heads. This was terrible. Geldof, the unguided missile, had boomeranged in their direction. The backlash began. In the days that followed there was much muttering about the inadequacy of celebrities, how they wouldn't follow the party line, how they didn't know what they were talking about, and how the campaign should never have enlisted their support in the first place. And anyway, whose idea had Live8 been in the first place? Er.

So is it campaigners and activists who change the world?

Up to a point. Certainly last year saw one of the biggest gatherings of protest at the way that Africa was being neglected and - in the case of the rich world's trade policies - wilfully maltreated that has ever been seen. A tremendous momentum built up in the United Kingdom with aid agencies, churches, trade unionists, student groups and others creating an impressive coalition demanding action. It impacted upon Tony Blair and Gordon Brown who, it has to be conceded, were receptive to change. Certainly the knowledge that there was a significant domestic political constituency which would award them brownie points for action on Africa did no harm. But it was not enough. Geldof had assumed that the cogency of the case made by the Commission for Africa, and the depth of the economic analysis on which it was based, would - in combination with this impressive phalanx of activism - be enough to do the trick. The trouble was there was no significant equivalent elsewhere. Campaign groups in France, Germany, Japan and - most crucially - the United States were nowhere near as influential. Though Blair and Brown were, for the first time, really pushing Africa's case at the top table, the rest of the world's leaders felt they could safely ignore them.

So how come so much was achieved?

When Bob Geldof finally realised that political leaders in the rest of the world were not under the same public pressure as Blair and Brown he acceded to Bono's request to do a Son of Live Aid concert. It was only when details of the Live8 concert in the backyard of each of the G8 leaders was made public that the mood began to change in the backroom preparations for Gleneagles. Suddenly the sherpas - as the top civil servants preparing summit agendas are known - began to put things on the table which they had earlier resolutely refused even to consider. That was when the significant increases in the annual aid commitment came on stream, and when the deal on debt was finally agreed.

So is it politicians who change the world?

Not exactly. Left to their own devices politicians will do as little as possible. The relationship between Africa and the developed world is a story of hopes raised, and constantly dashed, of promises broken and opportunities squandered. Pledges of "education for all" have gone unfunded. So have commitments on HIV and Aids. Initiatives to curb corruption went unratified and unimplemented. The world says "never again" after every major atrocity, but its politicians turned a blind eye to the trade in small arms. Trade rules are applied vexatiously. Debt forgiveness schemes are hedged about with intractable restrictions. Wealthy nations make well-intentioned pledges at international conferences only to later decide that the promises, or their timetable, were unrealistic. Goals are set, reset, and recalibrated yet again so that all the rich world ends up doing is mitigating the extent to which it has failed. The catalogue of shattered undertakings by the leaders of the wealthy world is a source of some shame. Without the spur of campaigners and activists little would happen. But there is something else too. At the time of the terrible Ethiopian famine of 1984-85 policy on development was, in British politics, handled by a minister who had less status than the poor sucker who was given Northern Ireland. Then Live Aid aroused the conscience of a new generation. It was seen by 98 per cent of all the television screens in the world. Among the fans watching Queen and Status Quo were two young men called Tony Blair and Gordon Brown. They were children of Live Aid and their conscience was seared in a way that could not be ignored decades later when they became Prime Minister and Chancellor of the Exchequer. It perhaps explains why they became the first politicians to take Africa to the top table.

So rock stars do change the world?

Oh all right then. But with a little help from their friends. Which includes all of us - fans, activists, politicians and now - as Project RED so clearly demonstrates - shoppers too. "Celebrity is ridiculous," said Bono yesterday, "but it is currency and I want to spend mine wisely". Who changes the world? The answer is all of us. For we each, in our very different ways, have our own currency to spend. And we must spend it wisely.

DOES FAME CARRY ANY REAL POLITICAL CLOUT?

Yes...

* By virtue of their fame, rock musicians or film stars can help raise public awareness of issues like the Ethiopian famine or Darfur

* Politicians are careful to take notice when big names become involved in a campaign and shame them into action

* Celebrity involvement can make campaigns fashionable, helping to build momentum that NGOs would otherwise struggle to achieve

No...

* Despite the participation of so many megastars, some activists believe the political outcome of Live8 fell well short of expectations

* NGOs, aid agencies, churches, student groups and others can be just as, if not more, effective in hammering home a political message and highlighting injustice

* Nothing can happen if politicians fail to take the right decisions