JAZZ / Slow burn: Phil Johnson on Betty Carter at the Royal Festival Hall

The secret of Betty Carter's unique style of jazz singing may well lie in her timing. Certainly, she seems to spend a lot of time looking at her watch. She is, she tells us, famous for overrunning her allotted span. A set from Ronnie Scott's band was followed by an interval and there were two long numbers from Carter's trio before the star made her entrance. She had hardly got going before those members of the audience with babysitting commitments started hustling out in the intervals between numbers. They missed the peak of the show: Carter burns on a slow fuse.

At least the band was worth hearing on its own. Geri Allen on piano, Dave Holland on bass and Jack DeJohnette on drums are a rhythm section to die for and they began in slow, meditative mood, easing through the changes of a Holland original and a Mingus cover with rare delicacy. When Carter entered from stage left, in an ample shimmer of brown crushed velvet, she immediately kicked them into the gear reserved for her normal accompanists, switching DeJohnette on to full power and beginning a long, scat-singing intro where her voice acted as a trumpet substitute. The mechanics of scat - a dooby-doo here, a ba-ba-rabop there - can now appear hackneyed, but Carter brings a real art to the form. Typically, she intimidates her musicians into a dialogue by standing very close to each of them in turn, forcing them to echo her flights of fancy by sheer power of personality, until the stylised baby-talk of her vocal is picked up by the accents of each instrument.

When she started to deal with real words, in a slowish ballad called 'Love Notes', the effect was underwhelming, as if normal lyrics couldn't contain the emotion that she puts into pure sound. But a wonderfully disrespectful version of 'Lover Man' late in the set confirmed her brilliance. Starting out as a percussive Latin groove, and then moving, through Allen's Monkish piano middle-eight into a bluesy honky-tonk lament, the beautiful song was remade in Carter's image, her dark swooning voice continually giving a dying fall to the lovelorn lyric.

A series of duets with the band continued the set almost to its end, Carter - despite synchronising watches with DeJohnette - appearing to ignore the impending close by allowing her accompanists as much time as they required. A ravishing 'If I Should Lose You', with Allen was followed by 'All or Nothing at All' in tandem with Holland's bass, before she exchanged rhythmic tic-tac with DeJohnette and a bowed solo from Holland introduced 'Daydream', the final number.

It was a proper jazz-diva performance to be sure, though a very late licensed night-club is still the ultimate arena for Carter's gifts.