The 34 year-old Joe Orton finished writing What the Butler Saw just a month before he was murdered by his lover Kenneth Halliwell in the summer of 1967. Jeremy Sams' fine production confirms this play as one of the great English farces. It's a wonderfully funny and strangely disturbing piece about sex, psychiatrists, madness and the problem of identity.

A young girl (Kate Alderton) arrives for a job interview with an eminent doctor. She loses her clothes inside two minutes and is certified insane within ten. A young man comes to blackmail the doctor's nymphomaniac wife and he too is naked in moments. When a policeman calls, he's soon parted from his uniform. Girls dress as boys, boys as girls and policemen as Greek gods. Just a normal day at the psychiatrist's office.

Michael Pennington as Dr Prentice leads this talented cast effortlessly. One of the keys to playing Orton is getting the speed right - fast enough to keep the farce going at a manic pace, but slow enough to allow the audience to enjoy the elegantly crafted and wickedly subversive dialogue. Pennington judges this to perfection in a superb central performance, and Jane Asher as Mrs Prentice follows his lead.

Benjamin Whitrow will be good as Dr Rance when he becomes more familiar with the words. The press night followed immediately the dress rehearsal with no pause for previews, but there's nothing wrong with this production that a week or so on the road won't put right. Thankfully Whitrow breaks free of the tradition of Ralph Richardson, who played Rance in 1969, and makes the role his own.

Edward Clarke plays the boy Nicholas Beckett in a way which would have delighted the author. Indeed, the great strength of this production is how unerringly faithful it is to both the letter and spirit of Orton.

Crucial to this is the contribution of the set designer Robert Jones. At the end of the evening, the dramatic appearance of a cage and a ladder are essential to the play's Dionysian apotheosis and this is magnificently realised. The final images of this production are a triumph.

This is about as good as Orton gets. If you don't enjoy it, then you probably just don't like Joe Orton.

Robert Hole (reviewed at Theatre Royal, Bath)