Detractors would suggest that Ian Brown's ongoing career is one of the great mysteries of modern rock. Audibly the one weak link in a band of startling talents, he has somehow ended up the solitary Stone Rose with a career that's not merely functioning, but in rude health: a decade after their miserable demise, he is still playing sold-out gigs.

Tonight's audience is old enough to recall the brief, dizzying period in which Brown fronted the most exciting band in the world and, as their tendency to erupt into terrace chanting between songs suggests, heavy on the kind of devotee who has more in common with a die-hard football supporter than your standard flighty rock fan. Nevertheless, you wonder how many of them would be here were it not for Brown's pragmatic volte face regarding performing Stone Roses songs: tonight's set is bookended by I Wanna Be Adored and I Am the Resurrection.

However, if your only motivation was to hear Stone Roses songs performed live, you would be better off with one of the many tribute bands. The line that Ian Brown cannot sing has been repeated so often that it feels very tired, but the degree to which he cannot sing still has the capacity to shake you awake. Here, his voice is a muffled, gloomy honk, like a despondent goose wearing a balaclava. It has an inexplicably ominous quality, which does for even the perkiest tracks from his solo career. This is a shame. On record, his songs have an artless charm - whatever accusations you want to level at him, you could never call My Star or Street Children contrived. But live, everything seems to descend into mid-tempo sludge.

For all that, watching him is still weirdly entertaining. Despite the legions of northern frontmen who have copied his swagger, Brown remains a unique and defiantly odd figure, as evidenced by his between-song banter. He engages in a perplexing but determined effort to upset the audience by repeatedly asking if there is anyone here from Portsmouth, the town's arch football rivals. Then he complains that they are not dancing properly: "More shoulder shuffling," he protests, offering a quick demonstration. Then he starts going on about Portsmouth again: cue boos and expletive-laden catcalls of a quite remarkable vehemence. Up on stage, Ian Brown appears to be chuckling to himself: one of the great mysteries of modern rock, as unfathomable as ever.

· At Academy, Bristol, tonight. Box office: 0844 477 2000. Then touring.