For a band who once spent eight weeks at number one in the singles chart, Shakespear's Sister are little-remembered today, and Marcella Detroit, the half who wasn't married to Dave Stewart, even less so. She may have possessed an air-horn voice, but as soon as they split up (onstage, while collecting the 1992 Ivor Novello award for best album) she entered the way-station reserved for former members of semi-famous bands.

Eight years and two solo albums later, Detroit is still best remembered as a Sister, but she's doing it for herself these days, with the help of a passionate following. There are enough fans of her songwriterly guitar-pop to pack this small room in the middle of the City and leave a queue of people in rectangular glasses trailing down the block.

It's hard to distinguish the similarly-bespectacled Detroit from her people, except that her long black hair means that Nana Mouskouri is never far from one's thoughts. In every other sense, Detroit is one with the audience, vocalising the expectations of thirty-somethings poised between Nikes and Sainsbury's. Playing guitar and sometimes perching on the edge of the low stage, she's melancholy and regretful. "I've got a lust for life," she broods, sounding anything but lustful on a song that lifts the chorus - but none of the joie de vivre - from the Iggy Pop hit.

A slow start, aggravated by her refusal to speak between numbers, gives way to peaks of intensity during which she scales mountains and heads for the stratosphere. She really has got a powerful voice, and sometimes the songs are almost worthy. They fall into three camps: dull countryish, vibrant R&B and Shakespear's Sister, which she saves till the end and makes a show of reluctance about playing.

"I don't know that one," she claims when someone requests Stay, the million-selling single that put her and Siobhan Fahey on the map. "Well, I do but they don't," she gestures at her hired hands.

But why so coy? It's what the people have come for, after all, and she finally obliges with a version whose rancour probably owes something to the lack of diplomatic relations between her and Fahey. Lay Down Sally, the tune she wrote with Eric Clapton when she was only 18, if you believe her biography, follows, and that's it. Back to the Renault Espaces for the crowd and back to a quiet California life for Detroit, both parties fulfilled.