STILL thrilling huge audiences more than 25 years into their career, U2 become ever more impressive in their longevity, integrity, capacity for reinvention and willingness to tackle geopolitical issues. On Tuesday, Manchester witnessed the first UK show of 2005 by the Dublin quartet memorably dubbed “rock’s last superpower” by the Times critic David Sinclair when their Vertigo tour opened in San Diego back in March.

Opening and closing with the chart-topping turbine blast of Vertigo itself, the Manchester concert was a triumph of old-school U2 values. Perched on an unobtrusively high-tech stage, the fortysomething foursome rattled and roared like a super-sized garage band. Their ability to sound both sonically stripped down and huge was striking.

Vintage crowd-pleasers including I Will Follow, New Year’s Day and Sunday Bloody Sunday provided early peaks in a set that relied heavily on the monochrome certainties, broad brushstrokes and choppy guitar ripples of the band’s 1980s heyday. But audience interest dipped noticeably during more workmanlike recent tracks such as Miracle Drug and City of Blinding Lights. For all their revitalised commercial fortunes, U2’s post-millennial albums have been light on big ideas or strong melodies.

Inevitably, Bono’s rambling stage monologues focused on Live 8 and Africa. Bathed in the afterglow of a rousing Where the Streets Have No Name, he thanked Tony Blair and Gordon Brown for their recent action on debt relief. With the Universal Declaration of Human Rights scrolling rather pointlessly across the giant video wall behind him, the singer whipped the crowd into a mass phone texting frenzy for the Make Poverty History campaign.

All very commendable, and Bono deserves credit for playing a bigger political poker game than any number of posturing rebel rockers. But even so, many of his passionate platitudes in Manchester sounded more like those of a careerist politician than an intelligent, questioning artist. Maybe trading photo opportunities for favours with Blair and Bush has had a Faustian effect on Bono.

Clocking in at over two hours, the show’s sluggish mid-section could have benefited from some of the grand conceptual excesses of U2’s early 1990s flirtation with disco kitsch and arch self-parody.

A clutch of songs from this rich period, such as The Fly and Mysterious Ways, were saved for the encore and proved refreshingly free of wholesome, righteous sentiments.

After Bono has single-handedly made poverty history, a little more of this challenging moral complexity would not go amiss. U2 are impressive elder statesmen in 2005, but they also play it very safe.