Brit-rock jazzers Acoustic Ladyland talk about the "Rochford effect", the special swell of audience acclaim every time they namecheck their big-haired drummer Seb. Guitarist Mike Stern's band is likely to get a similar response every time they announce 23-year-old drummer Kim Thompson.

Lithe and tiny, with a sensible hat that keeps her hair out of the way (like Rosie the Riveter's) she does everything you expect from a fusion drummer, from restrained grooves through brush-fuelled ballads to swaggering OTT solos. More than that, she has a nice approach to Stern's tunes; where tenor saxophonist Bob Franceschini flies over them like a deranged snowboarder, Thompson digs deep into their sneaky shapes and structures.

Stern's recent albums Voices and These Times have made extensive use of vocals, with individualistic guests such as Richard Bona and Arto Tuncboyaciyan. But for his first Ronnie's residency, Stern's challenge is to represent his widescreen conceptions in an intimate space with an instrumental quartet. And it works. He plays the tune What Might Have Been with the ease of a vocalist, nicely counterpointed by Chris Minh Doky's resonant electric upright bass and Thompson's drum pulse; she never loses concentration, however minimal the part.

The band kicks off with Play, a super-tight head over a spacious groove that soon evolves into a fast blues. Stern plays a solo spot: he's an inventive improviser with an instinct for structure that was less apparent when he worked for Miles Davis. He has also embraced the pleasures of melody: he's not afraid to play a long theme statement while celebrating the small details of expression and accompaniment.

When things go particularly well in the interplay between the four musicians, Thompson flashes a lovely smile. Stern grins with the confidence of a leader who knows he has a cracking band. And it's only Thompson's first gig with them - what will they be like by Saturday?

· Until Saturday May 14. Box office: 020-7439 0747.