"Bit worried about tonight," a jazz fan tells his friend as we're queuing for the opening night of a tour that brings together folk legend June Tabor with jazz veterans Iain Ballamy and Huw Warren. "I hope they manage to jazz her up enough." Therein lies the problem - while folk tunes mutate over hundreds of years, a jazz musician must treat melody as putty in his hands or risk alienating his audience. Tonight, this occasionally makes for occasional uneasy juxtaposition; a collision of values rather than a seamless fusion.

The most dramatic example occurs following a heart-chilling (and distinctly improv-free) rendition of an old George Butterworth Shropshire ballad about the evils of sending young men off to war. Singing the song appears to leave Tabor quivering with barely suppressed rage, but directly after she has stalked without warning from the stage, Warren incongruously launches into an upbeat, scrambled jazz piano solo. "Sit tight folks, here comes the clever stuff," would appear to be the message.

A version of Noel Coward's Mad About the Boy finds Ballamy struggling to follow Tabor's achingly soulful words with a solo full of tricks-of-the-trade sax licks. And then things improve. A spectral stillness haunts an unnamed Ballamy tune with words by Tabor, and the piece features a repeated twinkling sax/piano figure which perfectly offsets Tabor's silky lyricism.

Robert Burn's song Lassie Lie Near Me finds all three musicians sliding comfortably into the same musical glove. Warren's accompaniment is ocean-deep and he leaves wide open spaces for Tabor's breathy incantations. Ballamy then lends a fitful snake-charmer's clarinet melody to a vaguely Latin-sounding ballad based on an old Arabic love-lyric. Once again, Warrens's ostentatious piano trills almost spoil the flow, but by now the atmosphere in the auditorium suggests that jazz and folk fans are breathing a collective sigh of relief.

· At Cambridge Modern Jazz (01223 35785) tomorrow, then touring