Going to hear your favourite pop band and finding half the lineup is different would be a surprise, prevent the music from sounding like the record, and probably leave you feeling shortchanged. This happens in jazz all the time, and nobody minds at all. It fits with the notion that the music is a work in progress - anybody with the ears, skills and reflexes to listen and respond can drop into a group they don't belong to, and help reinvent its identity on the spot.
Julian Marc Stringle, the British virtuoso clarinetist who looks as if he could have been in T.Rex and plays like Benny Goodman, joined the eclectic world-jazz group Orquestra Mahatma for a pre-show gig in the National Theatre's foyer. The group's typical mix of Latin-American jazz, central and eastern European folk music, South Africa, Scotland and barn-dance Tennessee thus became skewed toward Stringle's favourite patch, mainstream jazz swing.
Blending the 1930s swing hit I Got Rhythm with a flying Charlie Parker bebop classic, the band reminded insiders that one of bop's standard procedures was to rip off Broadway chord progressions and stack them full of extra notes. But for those who didn't know that, the piece was just an exhilarating swing jam, with Stringle's shapely phrasing and rounded sound cruising over Paul Clarvis's percussion style of arrhythmic stutters and crash stops, and a long-striding ride-cymbal pulse.
Stringle brought both Benny Goodman and bebop to a fine account of After You've Gone, beginning with a delectably sonorous and conspiratorial unaccompanied overture. Stuart Hall added his signature mix of Stephane Grappelli lyricism and abstract angularity, and he and Stringle briefly tussled in an animated collective jam. Standard songs dominated the gig but Clarvis's machine-gun flurries, hangs and clickety knitting-needle sounds, and Hall's raw sawing segueing into romantic swirls, ensured it remained very definitely Orquestra Mahatma's left-field idea of a standard set.
· At the Lord Rookwood, London E11, on February 14. Box office: 020-8989 8129.
