Fewer than three stars for the world's premier acoustic-piano jazz trio? Sadly so, and the lone star you do see was earned only by a late rally in a truncated and disappointing performance by KJ and his musical soulmates, bassist Gary Peacock and drummer Jack DeJohnette.

Rumour has it that the diminutive US keyboard giant has been battling the debilitating illness ME, so a certain amount of planning might have been wise for this eagerly awaited concert, his first in London for eight years. Instead, he opened with 45 minutes of inconsequential noodling, mostly around a single chord-base. Top team players Peacock and DeJohnette found themselves sidelined as they waited in vain for a game-plan to appear, and fans were sitting on their hands in dismay.

In his early days, Jarrett annoyed critics only with his high-pitched "vocals" during solos. Last night the temptation was strong to yell "Play something!" at a trio whose wondrous cohesion had produced such in-person masterpieces as Standards in Norway and Tokyo '96.

Even at his most vague, though, Jarrett has always been fascinating to watch. In addition to his strange head-twists and moans of self-exhortation, he introduced a new mannerism: rising from the piano bench while playing and half-turning to the audience with oddly unseeing eyes. This had the unsettling effect of making his hands look disembodied, as if operated by somebody else.

Nearly an hour of fitful meandering through hymnal, bluesy and vaguely abstract fields had passed when Jarrett suddenly eased into a beautiful reading of the Matt Dennis ballad Angel Eyes. The audience sighed with pleasure and relief. For a few minutes his superb touch, suave chord voicings and inspired right-hand meandering were all there. A short take of the loping Sonny Rollins standard Doxy confirmed that everything was in perfect working order, but time was almost up.

A brisk, boppish encore and another short but lustrous ballad, When I Fall in Love, and they were gone. They return tomorrow night, when one hopes the Jarrett fireworks will flicker earlier and stay alight longer.