I said I, Barbican Theatre, London

In the early Eighties, the ultra-talented Flemish choreographer Anne Teresa de Keersmaeker wowed us with her fiercely perfect, excitingly avant-garde pieces. In 1992, she succeeded Mark Morris at Brussels' national opera house and thereby became accepted into the mainstream. Yet she has always remained true to her radical, serious self.

In the 21-year string of works behind her (she is now 41) she has oscillated between a pure dance approach, closely tied to its music, and dance theatre mixing different media. Her latest piece to visit London, i said i (1999), belongs to the second category. It uses the dancers of her company Rosas to act out their own intense scenes and to speak text from Peter Handke's play Self-Accusation, as well as to dance, while two music ensembles – one classical, the other contemporary – play in alternation. At two and half hours without an interval, the prospect seemed rather daunting and the Barbican kindly distributed water bottles to critics. Some of us, though, were less concerned about mild dehydration than the law that says what goes in must come out.

The lengthy quotes from Handke are also concerned with laws – the laws of becoming an individual, the laws of fitting into a group, the laws of an oppressive society. Sandwiched in between these recitations are scenes in which the performers rush about, assemble junk, remove their clothes, dance sequences that might start with one person and gain others. Taka Shamoto has a big humiliating tantrum in which she hurls insults (in Japanese) and erupts into the audience. Fumiyo Ikeda, a Rosas dancer from way back, performs a lengthy solo, the movement as fractured as the structure.

The minutes tick on slowly. Some people left. Others longed to follow them. When a man, victimised by the rest of the group on stage, indignantly asked "Which laws of the theatre did I violate?", we all burst out laughing. No one in the audience actually hissed out an answer, but the law of avoiding boredom would have been top of my list.

I have always admired the low, lean outlines and rhythmic patterns of Keersmaeker's dance, but here this seemed desultory and throwaway. The passages of chaotic stage business were mostly irritating, Fabrizio Cassol's jazz saxophone screeched unpleasantly, although DJ Grazzhoppa's solo sound-spin on his turntables was fun. Perversely, for a choreographer, it is the spoken text that is the piece's most powerful and evocative component: repetitious phrases that build accumulatively like dance numbers, compellingly delivered by each speaking dancer.

When the final speech ended and the lights dimmed, when the Ictus ensemble began their long Brahms recital, you felt you had reached a beautiful, suspended quietude and despite all the purgatorial moments you had lived something worthwhile. i said i isn't a dud; it's just that you wouldn't want to do it too often.

To 9 September, 020-7638 8891