What never turns you on

As 'Voyeurz' struts into town,

All London is in a lather of excitement over Voyeurz, the new "musical revue" that opens at the Whitehall Theatre on Monday. Why, even the Royal Court, that bastion of new writing, has brought forward the start-time of its own Monday-night premiere to allow dedicated critics to hotfoot it to the rival thespian - sorry, lesbian - attractions across town. For the new show, set in a Manhattan nightclub, is all about a young girl venturing into the uncharted caverns of her own sexuality, and it's stuffed to the gills with hot sapphic action. Apparently.

But the slavering anticipation probably has rather less to do with the show itself than the prospect of the reviews. It takes a huge leap of the imagination to picture any of the critics giving the thumbs-up to a show starring the members, if that's the word, of Fem 2 Fem, the notably talentless "lipstick lesbian" quartet.

You have to applaud producer and co-director Michael White's courage. He has spotted that lesbianism is chic, but may have miscalculated in his assumption that it's marketable. It was White who brought us Oh, Calcutta! all those years ago. In its wake, The Dirtiest Show in Town, Let My People Come and Carte Blanche offered further lashings of naked flesh. So White and stage nudity used to enjoy an intimate relationship. But that was back in the 1970s, when a naked body on stage performed an entirely different, and entirely basic function. Nudity was unapologetically offered as a stimulant to the audience's groin.

But White and Co were so busy celebrating the new liberty, they didn't realise how singularly unerotic nudity in the theatre actually is. Even Clifford Williams, who directed Oh, Calcutta! in both London and Paris, admits as much. "A slow striptease in the right lighting might be erotic. But quickly throwing off your clothes isn't."

Williams is something of a pioneer in this department. In 1965 he cast a gaggle of strippers for the orgy in Schoenberg's opera Moses und Aron directed by Peter Hall at the Royal Opera House. To circumvent the contortionist rules on nudity (eg nipples had to be covered if the actress moved, but could be exposed if she stood still), he had to ask the performers to shave off their pubic hair, seal off the offending area with elastoplast and stick on an artificial replacement. In 1968, directing Dr Faustus at Stratford, he had Helen of Troy walk diagonally downstage clad in nothing but gold paint.

Since the Lord Chamberlain hung up his wig, the great and good of the profession have dutifully flashed the relevant bits if called for: think of Peter Firth in Equus, Diana Rigg in Abelard and Eloise, Ian McKellen in Coriolanus. But the stage has never been able, or scarcely even tried, to use nudity the way the screen has. "I'm not sure that you can actually achieve any kind of sexual response in the theatre," says David Storey, whose recently revived play The Changing Room was a positive festival of male genitalia. "In the cinema, there is a precondition: you're perceiving through a keyhole, which is the lens of the camera. A camera is an objective instrument but it's highly subjective in what it shows. The subjectivity there is controlled in a way that you can't in the theatre."

Context is all. Life Class, another play of Storey's from the early 1970s, calls for an actress to play a nude model. And, just like a life class, the theatre contrives to drain the naked form of all sexuality. This may explain why actresses have no quarrel with playing women who pose for painters. Stanley Spencer's two wives, played by Anna Chancellor and Deborah Findlay, sit in Pam Gems's Stanley (currently at the National). Flora Crewe has her portrait painted in Tom Stoppard's Indian Ink - a scene the author may have found it easier to write for Felicity Kendal when it was intended merely for radio broadcast.

But if theatre cannot replicate the screen's intimacy with (mostly female) nakedness, it can achieve an array of more interesting effects. In the theatre, nudity actually means something. When Simon Russell Beale undressed in Edward II, the character was humiliated by nakedness, then anally assassinated. In Killer Joe, the thrilling play by Tracy Letts about trailer-trash murder, Killer Joe Cooper orders Dottie to undress as a way of establishing a charismatic power over her. When Joe and Sharla later stroll about stitchless from the waist down, it announces their shocking withdrawal from the moral order.

In the majority of instances nudity equals bathtime - most famously in Marat / Sade - and a kind of cleansing for the character. In Pygmalion, Frances Barber's Eliza leapt into the tub to wash away the flower girl. At the end of Ayckbourn's Way Upstream, the surviving couple throw themselves naked into the water to celebrate their liberation from the boat's tyrannical captain.

And then there was Dead Funny, Terry Johnson's play about comedy and marital breakdown, which skilfully aligned the audience's embarrassment with that of the characters. Richard the gynaecologist is persuaded by his wife, who's desperate to conceive, to undress as part of a course in sexual therapy. The audience communally cringes as she makes to touch the offending organ, but the doorbell spares our collective blushes. One night at the Hampstead Theatre, David Haig, who played Richard, went sick and Johnson, a sometime actor, had to take the role himself, which might make him think twice next time he writes the words "He removes his underpants". He deployed the script as a figleaf.

In the West End transfer and tour, Kevin McNally played the role 400 times. "It always feels really bizarre at first," he says, "but it's amazing how quickly you can get used to it. Dead Funny was a lot easier because the character I was playing was more embarrassed about having his clothes off than I was. Towards the end I would think, this is just a ludicrous thing to be doing - I'm a 40-year-old man with three children and every day I'm going to a public place and waggling my willy about. It doesn't seem to me to be a very sensible way of making a living." McNally is something of a serial trouser-dropper, and recalls taking issue with actresses who claimed that most stage nudity exploited women.

If there ever was an imbalance, these days it has been redressed. From The Changing Room to Burning Blue, the theatre offers sundry helpings of meat and two veg. Frances Barber, who has twice been totally or partly naked on-stage, claims that "actresses are asked to do it more often. But they were kicking up a fuss about it, and saying 'I'm not going to do it unless he does'. Most of us felt that it simply wasn't fair."

But however much that unfairness has been eradicated within the profession, there's still no accounting for (mostly male) critical reaction. When Barber, who had to put up with "My Bare Lady" headlines after Pygmalion, played Lady Macbeth at the Royal Exchange, she pulled down her dress to illustrate the line "Unsex me here". "It was the reverse of titillation. But one of the critics in Manchester told the audience where to sit to get an eyeful. We did sell all those seats, so I used to cheat everybody and pretend I was going to do it on that side and then whisk around and do it on the other side of the auditorium."

The frankest nude happening took place earlier this month at the Royal Court. Body Talk collated interviews with members of the public and the cast into a discussion of the male body, in which the bathing actors were nude for the duration of the work. There were 20 minutes on foreskins alone. "It wasn't nudity as in 'I have to be nude in this scene'," says Stephen Daldry, who directed it. "It was nudity as in 'this is my body, this is what I hate and this is what I like about it; this is my emotional reality because of this body'. So it was far more exposing than normal nudity."

So exposing, in fact, that Daldry decreed nudity for all during rehearsal. "I always felt that if you're asking actors to take their clothes off, everybody in the rehearsal room should take their clothes off. Me, the stage management team, anybody that came in. At one point we were going to ask the audience to take their clothes off as well. It would have been fascinating to see who would come. 'If you'd like to come and see this show, do. But you have to take your clothes.' Would you have come?" Well, would you?

'Voyeurz' opens Monday (0171-369 1735)