THEATRE / Habeas Corpus, Donmar Warehouse, London

Sam Mendes has exhumed Alan Bennett's breast-obsessed farce with a brain. But does he know what he's grappling with?

Mammaries and mortality loom large in Habeas Corpus, Alan Bennett's blissfully funny 1973 farce. Like some saucy Magill seaside postcard as retouched by Magritte, or an end-of-the-pier romp reorganised by Orton, the piece shows how a collection of stock types from Hove (randy GP, sex-starved wife, flat-chested spinster who longs to be stacked like the Cairngorms, etc) find themselves propelled into the permissive society with the arrival of a false-breast fitter from Leatherhead (superb Jason Watkins). Identities are mistaken, the wrong knockers admiringly fondled, and libidos burst out of enforced hibernation.

Putting the focus on a couple of doctors who want to ensnare each other for professional malpractice enables Habeas Corpus to be in two minds about the human body. The job is a licence for roving hands and eyes and the play is very droll about the parless protocols of touch. ("Touching is what loved ones are for," declares the permanently affronted Lady Rumpers, "because loving takes the sting out of it.") But being a doctor also offers extensive opportunities for getting to grips with the body at its least lovely and most mortal. Hence the conclusion that you should get as much sex in as you can before the only thing that's rampant about you is the rot.

Sam Mendes's revival at the Donmar boasts a crack cast but, for me, despite deliriously enjoyable patches, the staging did not totally work. This was no fault of Brenda Blethyn, who airs her talent for grieving querulousness to splendid effect as the tweed-and-pearls doctor's wife in whom the would- be raver is awakened by the falsey-fitter's erring touch. Celia Imrie is also superbly centre-target as Lady Rumpers, an old colonial who clearly emerged from the womb with a large stiff handbag over her arm and a booming complaint on her lips.

Some things have been misjudged, however. The constant lighting changes to underline the play's tricky tonal shifts into pastiche verse, cod song- and-dance and direct-to-audience address, give this register-hopping an unduly galumphing, arbitrary feel instead of the spirited silliness that's required. For a play about how we're trapped in the body, Habeas Corpus is itself paradoxically disembodied, making do with a few chairs and dispensing with the usual material environment of farce, that fraught obstacle-course of doors, hiding places and hostile objects. But if this calculated incongruity is to have a full comic payoff, you need a tension between the abstract staging and the old-fashioned proscenium-framed box that is farce's customary habitat. The Donmar offers too open a space and the play does not look at home in it.

That fine actor, Jim Broadbent, strikes me as basically mis-cast in the role of Wicksteed, the lecherous GP. The randiness should spring out from behind a surface of reassuring respectability. But would you really trust someone who looks so interestingly and constitutionally dodgy? He is at his best in the jerky, desperate dance routine at the end, which demonstrates that life is a Totentanz, as well as a mating dance.

To 27 July. Booking: 0171-369 1732