Green Gartside, Luminaire, London

"Oh, blimey, crikey - am I supposed to start?" Green Gartside asks. The nerves are understandable. This is the fourth low-key gig this year for the 50-year-old who essentially is Scritti Politti, and the first that a journalist has attended.

Before this, for 26 years, there have been no gigs at all - not since a 1980 show, when a combination of crippling stage fright and a long-term diet based almost entirely on speed sent Gartside into a panic attack so severe it felt like death, and briefly struck him dumb. So seeing him up on stage in 2006 is almost unbelievable.

In the intervening quarter-century, Scritti spanned British pop's range of possibilities and seemed to find them all wanting. Forming in Leeds after seeing The Sex Pistols, they became a Camden squat-land collective, devouring Marxist critical theory and applying it to pop so remorselessly that, after several landmark lo-fi singles, they became too self-conscious to make it.

Gartside re-emerged from this stasis and his 1980 collapse as a genuine pop star. His talent was hinted at in the aching, slippery beauty of "The Sweetest Girl", and full-blown by Cupid & Psyche 85, a lush, sequencer-driven sonic landmark that was inspired by and then in turn inspired black US pop, arguably right up to Timbaland's micro-sliced beats today.

Gartside's melodic instincts also led him high into the transatlantic charts, with hits such as "The Perfect Way" (covered by an admiring Miles Davis). The 1988 follow-up to Cupid, Provision (on which Davis played) maintained some sort of momentum. But in the yawning gap between that and the hip-hop-infused Anomie & Bonhomie (1999), Gartside's perfectionism seemed to freeze him again, returning him to his natural state - that of a beloved outsider with supreme pop instincts that he's too fragile to enact.

All that history is implicit as Gartside takes the stage. But all he plays are 10 songs from his latest project. Simply ignoring the possibility of 1980s nostalgia, he instead unveils a talent as unclassifiable and undimmed as ever.

He met his new band socially in his local Hackney pub, and some of them have not played in public before; an amateurish policy that puts them in line with the original Scritti. Skilled musicians clearly playing for pleasure, they suit a man who has relinquished any notion of a career. They give brittle, ramshackle life to songs which show that Gartside still breathes out pop, if in air too rarefied to grace the charts.

"Snow" indicates where he's at. With its xylophone riffs, woodblock beats and not quite harmonies, it seems to sprout new genres with each verse. Subsequent songs also twist unexpectedly, products of a man who sees pop whole, without boundaries. "Robin Hood", for instance, is oompah psychedelia; "Cooking" contains a hip-hop breakdown, inside a Beatles song, inside a late-night torch lament, with no feeling of contradiction. But clever construction is matched by sumptuous texture and content. "Snow" is a baroque song of tested faith in love.

"After 6" inhabits a man terrified of intimacy, as Gartside (who got married this week), pleads: "Put your hands where I can see them." There are still darker hues to this desperation on the self-descriptive "Degradation" and the near-epic "Dr Abernathy", which is about addiction, in part to "methamphetamines for volunteers", but also to love. It begins as acoustic jazz, with Gartside regretting that "I don't quite hear the dime drop", as a desperate romantic venture expires. His summer breeze of a voice is to the fore, and he kisses the mic as he sings. He borrows from The Beatles again, without being subsumed by them, and recalls Steely Dan with some cool hipster couplets. But the strange chords and romantic ache are all his own. "I wonder how I'm feeling now?" he ponders, as the song frays and collapses.

He leaves the stage after 40 minutes or so, with one nervous, backward glance. But Gartside is moving forward again.