There aren't many Geris in contemporary music who spell their name with one R and an I, and unless a jazz fifth column had infiltrated the quiz night in your local, the name of Allen would never replace Halliwell. Yet Geri Allen, the remarkable Detroit pianist, is just as much a star in her own firmament.

You don't have to be familiar, as she is, with jazz piano legends such as Bill Evans or Keith Jarrett to get her message, but if you are, it deepens an already fascinating story. Ornette Coleman and the late Betty Carter are among the bandleaders who have confirmed their appreciation of all that by hiring her.

But in recent years Allen has more often shaped her own destiny, as a composer, improvisor and bandleader. She was at the Pizza Express for two nights last week, with a deft, sensitive trio featuring the Johnson brothers - Billy on bass and Mark on drums. As ever, the core of the performance was Allen's unwavering focus, zigzagging unpredictability of line and controlled energy.

Allen improvises in more extended lines, and with more composer-like variation of motif and mood within a solo than is common for many of her contemporaries on the instrument. And if her music can at times be prone to preoccupied longueurs and over-formality, the overwhelming impact was to suggest that a musician of sophistication and immense resources continues to grow.

Allen often began with unaccompanied overtures, rich arpeggiated melodies rippling and washing over quirkily lively left-hand figures, sometimes rather reminiscent of Wayne Shorter themes. Her timing is immaculate, enabling her to retain the sense of urgent movement in a fastmoving piece, whether pegging it explicitly to the beat, or suddenly flooding the music with melody so intensified it barely seems constructed of individual notes.

Slow features such as Angels emphasised Allen's concentration on the timbres of the piano, beginning obliquely and accelerating into a bell-pealing eagerness, with a little of Jarrett's clamorous harmony, while Feed the Fire - an uptempo postbop classic-to-be - brought out the best of Allen's originality of conception at speed (as well as the clean unfussiness of Johnson at the drums) before relaxing into a lazy blues.