There is a simple reason that U2 can make the casually patronising claim that they are "reapplying" to be the best band in the world, writes Peter Aspen of the Financial Times.

They know that they can wring more emotion from a five-minute song than most rock acts can manage in a whole tour's-worth of tantrums and tribulations. In truth, they have no rivals and they know it.

Who might they be? Mick Jagger croaking that he still cannot find any Satisfaction? Liam Gallagher and that impenetrable, in more senses than one, Wonderwall? Madonna, still in need of her Holiday? It matters, even in the garrulous arena inhabited by the stadium rock star, that you mean what you say and that what you say makes sense. U2 have always been famously unafraid to tackle the great transcendental issues; and now they reap the reward of that emotional investment.

When Bono dedicates a song to his just-departed father ("he has left the planet like Elvis"), it is moving. When he intones that "compromise is not a dirty word" in the middle of "Sunday Bloody Sunday", it is forceful. Earnestness, that deadly enemy of the ironic disdain which long ago ambushed the sensibility of popular culture, has its place too.

Not that Bono can't take a joke. His rolling around in leathers on the floor of a heart-shaped stage at London's Earls Court, trademark wrap-round shades predictably snatched off his face by adoring fans, has a touch more self-conscious showmanship than it used to. And when another fan from the front row hands him a freshly purchased T-shirt, he poses with it and looks up to the skies. Heaven is only another merchandising opportunity, even in the U2 universe.