Music: Music from the Yellow Shark, Frank Zappa / Ensemble Modern Royal Festival Hall, London

The late Frank was sadly unable to appear for this ultimate valediction of his role as a serious composer, but if he had, he would, you think, have taken comfort in the extent to which his facial hair-styles seemed to live on in many members of the audience. The yellow shark of the title lay pinned up behind the stage like a scruffy talisman and an air of expectation lay over the whole of the first, non-Zappa, half of the performance.

Opening with three studies by Conlon Nancarrow, the Ensemble demonstrated immediately their masterly grasp of difficult repertoire, the two pianos chattering away as if in binary code while the percussion sectionswapped roles in a see-saw of rhythmic accents, like chopsticks rattling on a plate. Study No 6 was achingly beautiful, the strains of a Mexican lullaby somehow emerging through the convulsive pitter-patter. Varese's Deserts followed, accompanied by a film by the video artist Bill Viola of underwater point-of-view shots, barren landscapes and, eventually, an interior scene in which a man moved slowly across a room. Meanwhile, the music - part live orchestra, part taped industrial sounds - reached a series of crescendos, matched at the end by a magnificent coup de film, when the man and his furniture were dashed to smithereens. It was difficult, it was pretentious, but it was also very well done, and it matched the accumulating tension and ecstatic release of the music marvellously. So how would Frank live up to that?

Brilliantly, of course. First assembled for a performance at the 1992 Frankfurt Festival, which was partly conducted by the composer, the music is a compendium of Zappa themes that he got up to speed on his trusty synclavier and then printed out as music for the orchestra to learn, the title emerging only as an afterthought. Beginning with a cheesy Star Wars-ish introduction, the Ensemble's programme mixed and matched movements from the original performance (available almost complete on the excellent Rykodisc album). Echoes of Boulez and Henze, at times rather too plinkety- plonk for comfort, were evident, but much of the music was quite superb, and the closing "G-Spot Tornado" was a tour de force of sustained action and invention. Only in "Bebop Tango," was there any real Mothers of Invention monkey-business (when the orchestra talked among themselves, loudly) and the concert ended in total adulation. The encore, though, was a bit of a disappointment; hoping maybe for "Peaches En Regalia", what we got was the Star Wars intro again. But the Zappa-philes went home happy, as they knew they would.