The Roots, Academy, Glasgow

To describe The Roots as just another hip-hop outfit would be to miss the point. To label them as a rock band, on the other hand, would be woefully inadequate.

To describe The Roots as just another hip-hop outfit would be to miss the point. To label them as a rock band, on the other hand, would be woefully inadequate. And to call them a techno outfit wouldn't be quite right either, but it's closer to the truth than you might initially suspect. That's one of the delightful qualities of this band (for they are a band, in the truest, collaborative sense of that word): they're a difficult-to-pigeonhole collection of innovators.

More than that, though,their reputation for providing an energising and exciting live experience is utterly well-deserved. Although critical opinion generally has it that The Roots's recorded output can be a pat-chy affair - the songs on the new album The Tipping Point are edited down from extended jam sessions, for example - it's precisely that freeform approach that works so well on stage.

In Glasgow, able support was provided by Estelle, whose more natural habitat is in the charts and on our TV screens, gracing every pop show doing the rounds. But while the west London hip-hop diva has all the clean-cut chart friendliness of a Natasha Bedingfield, she combines it with a more grimy, urban sound in the style of, say, Ms Dynamite. Estelle may match both of them in the glamour stakes, but it's her edge of street-worn credibility that makes her the ideal support for The Roots's conscious hip hop.

And so to the main event. (And, given The Roots's appearances on the festival circuit this year, gathering dumbstruck converts along the way, the Philadelphia musicians could soon be the main event at more than just their own headline shows. This gig was a sell-out, for a start.)

As the night progressed, it became apparent that there would be no such luxuries as mid-song breaks. The Roots hit the ground running and didn't stop until they pulled up panting just before the encore. In the interim, some songs morphed straight into each other, while others were threaded together by ?uestlove's strident drum fills. Almost like a DJ set with a full live band instead of turntables, it's a style that quite frankly yields a huge party momentum, be you a rocker, a hip-hopper, or both.

It was a celebration of black music in all its forms. The ghost of Jimi Hendrix was exhumed during the guitar-heavy coupling of "Panic" and "Break You Off", while the Grammy-winning single "You Got Me" and the most recent effort, "Don't Say Nuthin'", saw MC Black Thought revisit such past masters of hip hop as De La Soul. Even a midway, three-song acoustic guest spot by The Roots's guitarist collaborator Martin Luther called to mind Gil Scott-Heron, for its breezily intent lyrical flow, if not any overt politicism.

Towards the end, then, the band caved in entirely to their obvious passion for homage, with a medley of riffs and raps belonging to everyone from Jimi to Beyoncé. But it's not as though we grudge them such indulgences, for The Roots are writing their own chapter to add to the annals of their heroes' exploits.