Sometimes you have to pinch yourself. I had one of those moments watching the TV news, the weekend of the G8 summit in Genoa. While in the streets there was a riot going on, and one anti-globalisation protestor was being killed by a Rogue Trooper of the Italian reserve police, within the protected zone where the leaders of the big eight were meeting, there was at least a couple of interlopers.

It was a surreal moment. The television pictures showed four familiar figures shaking hands and embracing. Two of them were more familiar than the others – who themselves were world leaders. It was impossible to stifle a chuckle at the sheer bizarreness of the spectacle. For who was it whose image was being transmitted across the world cosying up to Tony Blair and Vladimir Putin, except two ould muckers from the Irish rock scene in the mid-to-late seventies -– Bono of the band U2 and Bob Geldof of The Boomtown Rats? As the realisation dawned that this was really happening before your very eyes, you could only shake your head and ask – twenty-five years ago, or so, did any of us have even the remotest idea that it would come to this?

I don't suppose we did...

It's a question that's especially relevant to this issue of hotpress, which marks one of the most significant landmarks in the history of Irish rock music. On August 25th, U2 play Slane Castle. They last played there in the summer of 1981, when they supported Thin Lizzy -– about 30,000 people showed up to see Ireland's biggest band of the moment at the height of their powers, on a bright and sunny gig that was basically modest in its aspirations and low-key in its flavour.

How time flies. And how things change. In contrast, in the wet and miserable summer of 2001, U2 have been forced to add a second date at Slane, on September 1st, selling out a record 160,000 tickets for the venue in a matter of minutes. And it doesn't stop there. U2 mania is beginning to grip. Fans are paying up to £1000, and more, for tickets to both shows. The sense of expectation and excitement is mounting, almost by the hour. It promises to be a remarkable sort of homecoming.

This is the gig that U2 were always destined to do. They have strong links with the castle, having recorded The Unforgettable Fire – the album on which they first linked up with Brian Eno and Daniel Lanois, and which changed the course of their career, and by extension the course of modern music – in this stately manor. It is, in any event, the ultimate Irish festival site: if there was one U2 gig not to miss, amongst all the gigs U2 have ever done, or at least done over the past fifteen years, you could argue that this is it. U2 at Slane Castle. And yet only 160,000 fans can be there. Are you going to be one of them? It's a question that those who don't have tickets yet are still asking themselves.

It'd be a brave man or woman who would claim to have seen the potential for this kind of vaulting success, this intensity of adulation, in the outfit that graced the stages of the Dandelion Market, McGonagles, the Project Arts Centre and the Baggot Inn in Dublin, or the Arcadia in Cork, at the end of the '70s. But there was something special, some unique dynamism, about the band from the start, of that there is no doubt – and it inspired a kind of fervour that few other emerging bands of the era, whether in Ireland, Britain or the U.S. could even dream of emulating. We saw a lot of it in hotpress, the love that their fans felt for U2, and lengths to which they would go in their devotion to the band and the cause. It was at least part of what made you feel that this one might just run and run – as indeed it has.

Of course you get from there to here by a series of accidents too numerous ever to be able even to make a stab at identifying. It's the music of chance and it has played a huge part in the scale of U2's impact, much as it does in a much more mundane way in all of our lives. Manager Paul McGuinness tells of how, at first, he turned down the request from Bob Geldof to get invovled in Band Aid. He subsequently did a U-turn, and Live Aid subsequently proved to be the most important show that the band had ever done – as a result of which the sales of their then current album The Unforgettable Fire shot through the roof, especially in America. What if they had stuck by their original decision?

Where would they be today? Who can possibly say?

Which is not to suggest that U2 haven't made their own luck – they have. Nor is it to suggest that the greatness of the music they have made is less than central to their status -– because, in truth, it is absolutely essential to it. Ask for a list of reasons why U2 have endured and it doesn't take long to realise that it is long and impressive. They are without doubt one of the most thoughtful, intelligent and articulate collectives ever to band together for the purpose of making a racket. They are also among the most genuine and decent. (I say these things knowing that to do so will provoke both sneers and cynicism among the band's detractors. But I know them well enough to say it with certainty and not give a fuck that other people might see it differently – as they are entitled to do). They have just about the smartest management in the business. And they work with a team of producers, designers, technicians and advisors that are of the highest calibre. And so the list goes on ...

And yet there is something else, that is harder to define, and that has often landed them in trouble – but that is still a key to what gives U2 their special edge. It was there from the start and it is there still – and it explains why Bono, and Geldof with him, ended up shooting the breeze with the likes of Blair and Putin in Genoa.

It was never enough for U2 to be in a pop group. Since they were teenagers, the members of the band – and Bono in particular – felt the need to grapple with the big issues. They had the admirable quality that they didn't give a shit how it made them look to people who didn't sympathise. They did what their convictions told them that they had to do. There was a spiritual dimension to their lives and their work when that was less than fashionable – but they stuck with it. And – by extension or otherwise – there was a political dimension to the way they looked at the world, and to the music that they made, that was restless and questioning and ambitious. In a way that artists are often supposed not to, they wanted to make a difference.

They wanted to change the world – and in many ways they have.

Along the way – like me and you, and I guess like most people reading this – they have made what, with hindsight, they probably regard as mistakes. But Bono was never afraid to look like a prat if there was a hope that a higher good was being served, or might be served in the long run. And as a result, U2 were and remain uniquely credible to those who know and love them and their music. This is at the heart of their achievement – that they care enough to examine the Big Picture, and to aspire to making a positive impression on how it looks at the end of the day – or at the end of their own adventure, whenever that transpires, at least.

Which is why I believe in the essential decency of what Bono has tried to achieve with Jubilee 2000. As a card-carrying atheist and a complete sceptic in relation to the bona fides of the Catholic church, was I impressed to see him meet the Pope? Certainly not. But I wouldn't expect him to care about that. The goal of Jubilee 2000 is a laudable one, and he's giving it his best shot – the way he does, when he looks at the world.

That kind of commitment has taken him and U2 a long way – and I don't begrudge him a bit of it. You could say that he ended up in the wrong place at the wrong time in Genoa. But then he's argued for a long time that the place to be was – or rather is – at the heart of the contradiction. So by all means let him know what you think of it. But if its his motivation you're questioning, or his presumptions, then you've got it wrong. Because that is part of what has made U2 the great and enduring phenomenon that they are.

Wait for it. When they play 'One' at Slane, it will light up the place like nothing has, ever before – a truly unforgettable fire. When you can write songs like that, and sing and play them with the depth and emotion that U2 do – then you have no need to apologise to anyone.

Twenty five years ago, or so, did any of us have the remotest idea that it would come to this? I can't claim that we did. But I'm glad that it has. And now, on with the show...