At a time when commercial hip-hop seems to have stalled, its artistic progress trapped between rock (represented by an increasingly compliant, MTV-friendly Eminem) and a hard place (the reactionary nu-gangsta of 50 Cent), Common harks back to what seems like an altogether more tolerant and positive period. Tonight, he respectfully reels off a checklist of artists who, he claims, are "classic". Alongside D'Angelo, Erykah Badu and the Roots, he names A Tribe Called Quest and De La Soul, whose Daisy Age baton the underground American rapper has picked up and carried into the mainstream, despite prevailing hip-hop fashions, and whose righteous socio-political concerns form the basis of his sound.

In flagrant disregard of the unwritten rule that decrees that live hip-hop must involve interminable funky jams, numerous rambling, spoken-word interludes and endless call-and-response-routines, Common's performance is refreshingly free of frills. His band - including a formidable scratch DJ - support him rather than grandstand, crotch-grabbing is restricted to the occasional real need to hoick up his tracksuit pants and the crowd are urged to throw their hands in the air only twice, since Common's business is not hip-hop cliche but communication. His fluid and braggadocio-free rhymes deal principally with what he describes as "liberation through struggle", and identify him as more Gil Scott-Heron than gangsta.

For all his consciousness-raising, however, and his desire to stretch the boundaries of what constitutes hip-hop by embracing swing, electro-funk, jazz and psychedelic rock on his current album, Electric Circus, Common is well aware of his primary role as entertainer. At one point, he gives a brief but impressive breakdancing demonstration, complete with headstand, while during the sweet and liquid Come Close, he hauls a female volunteer out of the front row and, while she perches happily on a stool, serenades her with "love shit" so eloquently that Mary J Blige - who guests on the recorded version - is barely missed. All of which provides a fair-enough summary of Common's claim as expressed in the perky I Got a Right Ta: "Hip-hop is changing - y'all want me to stay the same?"