Metamorphosis, Lyric Hammersmith, London <!-- none onestar twostar threestar fourstar fivestar -->

David Farr, the artistic director of the Lyric, has revealed that, a year ago, he and Gisli Orn Gardarsson, the head of the Icelandic company Vesturport, got to drinking and discovered that they shared a favourite story, Kafka's "Meta-morphosis". They agreed to dramatise it, and now we can see the results - and, well, I have to ask: did neither of them sober up for a whole year?

Gardarsson plays Gregor Samsa, the travelling salesman who wakes one day to find he has been transformed into a beetle. (He wears a suit and tie and speaks in a normal voice, but his family scream when they see him, and can't understand a word he says; he climbs the walls.)

The music has been composed by Warren Ellis and Nick Cave, the latter's voice only one of the dislocations to which the story has been subjected. Even worse is Gardarsson's idea that it would be "really ideal" for someone who likes "to work in a physical way". In fact, "Metamorphosis" is told from Gregor's point of view, and its desperate, painful tone depends on our being inside his head and feeling his frustration at being trapped in a body that will not do his bidding.

Far from being "physical", this is a story in which Gregor's movements become more circumscribed as his parents and younger sister, at first fearful, then resentful, confine him to his room and feed him less and less. Gregor's parents, in the story an elderly couple, are here young and limber - indeed, acrobatic, jumping onto the dining table or back flipping over it. When Gregor swings, like Tarzan, on a rope, the demands of physical theatre may be satisfied but the story's emotion and narrative are violated.

Worst of all, the two adaptors have done away with Kafka's three bearded lodgers and invented one, the domineering Herr Fischer. When he discovers Gregor's existence, Fischer departs, shouting at the family: "The time will come when we will clear the vermin from our society, and you are on the list!" This tacked-on symbolism changes the dreadful family from psychological tormentors to social victims.

As the father, Ingvar E Sigurdsson is suitably chilling, and Nina Dogg Filippusdottir makes an effective transition from docile schoolgirl to hardhearted woman. But their talents are squandered in a play whose authors show their reverence for Kafka by using him as an exercise mat.

To 28 October (08700 500 511)