On a day when arguably the biggest band in the world (and its manager Paul McGuinness) step up to receive the Freedom of Dublin City it may be worth borrowing from JFK: Citizens of Dublin, ask not what your city has done for you, but what U2 has done for your city.

Is it appropriate, some may wonder, that four musicians and a businessman should receive the same honour as Burmese human rights campaigner Aung San Suu Kyi on whom the Lord Mayor, Mary Freehill, will also bestow the award today? "I absoloutely think they deserve it," says David Heffernan, producer and director of the RTE music documentary series from a whisper to a scream. "When U2 emerged in the 70s Ireland was a grey, drab and uninspiring place. They went out and brought aspects of the modern world back to this country and they provided a fresh context for many people, not just musicians."

Not surprisingly, the Lord Mayor is quick to justify the decision: "I have been a great admirer of the group for many years. In a lot of ways they have put Dublin on the map when we weren't as popular as we are now. They also brought a lot of new tourists to Dublin to find out what the U2 city was like." The success of Bono, Edge, Larry, Adam (and Paul) could be viewed as a metaphor for how the capital has been transformed over the last two decades. Their journey from the Baggot Inn to international acclaim mirrors our odyssey from milky tea to frothy cappuccino.

The path from Marietta biscuits to amaretto. From a time when Ireland was a musical desert, where the likes of Rory Gallagher, Phil Lynott and Van Morrison had to leave to succeed to a place that boasts a thriving music infrastructure and makes staying at home an option for budding musicians. A city which once only attracted celebrities for its tax-free incentives is now a bustling metropolis that hosts major music, fashion and cultural events. U2 stride like a giant mascot over this shiny, happy Dublin. "They may be establishment, but that was always inevitable," said one commentator. "Before U2 there was no rock 'n' roll establishment."

One critic questioned why Paul McGuinness - who though he manages other acts through his company Principle Management and has many other business interests regards U2 as "the day job" - was getting the award. "What has he actually given back to Dublin? . . . He has benefited to the tune of millions from the spotty youths of Ireland and the band have tax-free status," she said.

Others argue that it is not the place of rock bands to "give something back". McGuinness says any philanthropic gestures, such as their support for new recording facilities in Dublin's City Arts Centre in the 1980s, are done "privately and quietly". In 1992, asked about a proposed free gig in the Phoenix Park, he made his feelings even clearer. ". . . The assumption that U2 owe as much as that [a free gig] to this city, or country, appears to me to be unfair and it is an assumption not made of any other Irish entertainer," he said.

If U2 did begin ostentatiously, throwing money at causes close to their hearts chances are it would be viewed with more than a touch of cynicism. Outside the maternity ward in the Rotunda Hospital in Dublin there is a plaque attached to an incubator. It reads; donated by Chris de Burgh. Oh, purleeze.

There is a school of thought, still pervasive in industry circles, that U2 was a dodgy little Dublin art-rock combo that was turned into a global phenomenon courtesy of the business wizardry of Paul McGuinness. Not so, said Michael Ross, editor of the Sunday Times culture section, who has followed the band's career from the early stages.

"From the start U2 were head, shoulders and torso above their Dublin contemporaries. They had a belief in themselves that was like a force field around them and McGuinness shared that belief. He grew as a manager while they grew as a band, and he needed them every bit as much as they needed him," he said.

Asked about McGuinness's business talents, one observer said that "Paul had one good idea in 1978 when he went backstage after seeing U2 for the first time and said `I didn't expect to be saying this, but I'd like to manage you, I think you're going to be great'."

Their story from that moment on is an integral part of global rock 'n' roll history. Snapshots in time: Bono singing Sunday Bloody Sunday at Live Aid, 1985; the band making it big in America with their fifth album The Joshua Tree - viewed by many as the definitive rock album of the eighties - in 1987; a massive McDonalds arch and gigantic lemon 10 years later, props for the Popmart tour, one of the most extensive rock 'n' roll circuses ever taken on the road.

Bono, like most of the group a committed Christian, has meanwhile embarked on a solo crusade to, if not save, then at least shake up the world.

Much of the time his job as rock star involves anything but music. Whether it has been anti-apartheid causes, Amnesty International, Jubilee 2000 or Sellafield, he has used his platform to rock the system. One of the highlights of this part-time career was his appearance at an awards ceremony in France at the time of Jacques Chirac's controversial nuclear testing.

"What a city," said a smiling Bono to huge applause.

"What a night." More applause.

"What a bomb." Uncomfortable, half hearted applause.

"What a mistake." See above.

"What a wanker you have for president." Loud booing.

While sources suggest personal relationships between the band and their manager are not as warm as in past years, their commitment to McGuinness, and his to the band, has never wavered. The royalties are split five ways between McGuinness and the other members of the band, a highly unusual arrangement for an act of their stature.

Now a multimillion pound generating corporation as well as a fully functioning and still evolving rock group, the U2 industry is a powerful force. A 1997 study suggested the five were worth around £300 million between them.

"I do think they are far, far better than any rock and roll band," said McGuinness. "I don't see anyone competing with U2 for that title. If anyone wants the title they are going to have to wrestle it from U2."

In the end, they will be assessed on their body of work. The fact that the irony-laden track Miss Sarajevo is one of the songs featured on George Michael's album Songs of the Last Century is telling, said David Heffernan.

"The impact of U2 and Van Morrison on popular culture can be compared with the impact Beckett and Joyce had on literature," he said.

And even though they become freemen of Dublin city today, U2 are likely to keep a cool head in relation to the implications of this honour. As Bono once put it, "Dublin people will never kiss ass, and I don't want them to kiss ass."