Cloud Nine, Crucible Sheffield

Caryl Churchill doesn't just bend genders in her comedy Cloud Nine: she turns them upside down and inside out, making incisive yet often farcical mockery of colonial and sexual repressions. Women's liberation, the outing of gay feelings and indeed sexual revolutions of all kinds are scrambled up in a brilliant jigsaw of pieces that, like life, don't always fit perfectly but which reveal an intriguing picture from two very different perspectives.

Played at a cracking pace with nifty use of several trapdoors and an upper balcony in both acts, Anna Mackmin's assured production revels in the twists and turns of Churchill's witty and penetrating ideas. In darkest Africa the natives are restless, the white masters are randy, and a crumpled Union Jack is the only thing hanging limply as the endless sexual shenanigans take their hilarious and often unexpected course in the first act. I'm not even convinced the horses would have been safe from the horny Brits making up this extended family. Queen Victoria reigns supreme, with duty and self-sacrifice prominent in their uptight, upright attitudes, some inherited, others adopted, and a few assumed - such as the cunning servant (Toby Dantzic) taking on the identity of his colonizing "father".

All convey the rigidity, superficiality and hypocrisy of this claustrophobic outpost and the era it encapsulates. Gender cross-casting adds to the exotic mix with the little woman, mother and wife played by Daniel Evans in a giddy performance that amounts to very much more than just a female impersonation. Paul Ritter invests a comical absurdity in Clive, the stereotypical patriarch, arrogant, con- descending and duplicitous towards all except his best chum.

But even that relationship flounders, though not because Harry Bagley (Nicolas Tennant) has been a cad with Clive's wife (wholly her fault, of course...) but because, horror of horrors, he reveals his feminine side. Crossing of sexual borders and extension of emotional boundaries come to the fore in Act Two when, although we are whizzed through a century to Thatcher's Britain, this family has miraculously aged just 25 years. The chickens have come home to roost in a London suburb. Clive's son (now played by Evans, his mother of the first act) is now a gay gardener, as repressed in his feminine straitjacket as his mother was in hers. Betty (Lucy Briers, who played her own son in Act One) has left Clive and discovers that she can in fact manage her life without a man. With actors doubling and sometimes tripling in roles, successfully swapping between genders and ages, and with ghosts of the past dropping in, it's a hard act to bring off. That it works so convincingly here is due to the huge versatility and commitment of the ensemble cast of seven actors, all exceptional in their distinctive portrayals of the variously related characters.

This Cloud Nine is right on target in its message about the representation of oppression.

To 19 June (0114 249 6000)