Look at what you’re wearing,” Neil Bartlett, writer, director, profligate translator and provocative performer demands. “Jeans, a T-shirt, trainers. What does it say?” Not, thankfully, that I really ought to have made more of a sartorial effort for our interview in the RSC’s Clapham rehearsal rooms. Breeches-deep in preparations for his bewilderingly cross-gartered Twelfth Night, Bartlett is busy unpacking the mercurial concept of staging gender.

“You and I are essentially wearing the same thing. But you are not dressing as a man. I am not dressing as a woman. We are not attempting to disguise our sex.” His slug of a moustache would surely prove something of a handicap. “Not really,” he says, smiling. “There are infinite ways to play gender.” He explains: “It can be ravishingly sexy, it can be very precisely unsexed. Some of my casting is completely true to type. Lady Olivia [Justine Mitchell] is an extraordinary, thoroughbred woman. Count Orsino [Jason Mer-rells] is a gorgeous man, but they’re playing opposite a Viola [Chris New] who is very obviously an attractive young man with false tits. It releases proceedings from the grip of naturalism immediately.”

Shakespeare’s slippery, androgynous twin, shipwrecked on Illyria’s shores, who disguises herself as a boy and falls desperately, inappropriately in love, is often played by a man. This year, Ed Hall and Declan Donnellan both staged their all-male Twelfth Nights at the Old Vic and The Swan theatres.

In Bartlett’s production, however, the male comic characters are also played by women. “They are the creators of mayhem in the play,” he says. “And to see Malvolio chased about by three expert comediennes in padded Y-fronts is a delicious sight. I cannot conceive of a more perfect Toby Belch than Marjorie Yates. Twelfth Night is this incredible dressing-up box of a play and everyone has to find their costume.

“To me it just isn’t strange,” Bartlett adds, “because I’ve never done anything else. One of the first pieces of theatre I ever did was called Dressing Up.”

As artistic director of the Lyric Hammersmith from 1994 to 2004, in recognition of which he was appointed OBE, Bartlett established the venue as a powerhouse of playfully reinventive theatre, from the English language premiere of Genet’s Splendid’s to his lauded adaptation of Dickens’s Oliver Twist.

“I’ve never been worried about what box I’m supposed to be in,” Bartlett says, which, given the number of strings to his creative bow (including award-winning novelist), is probably just as well. “And I ask my actors not to worry either.” This year, he directed Hayley Carmichael, Kathryn Hunter and Geraldine Alexander in The Maidsfor the Brighton Festival, though Genet wrote all three parts for men. Bartlett played still farther by asking his actors to switch roles every night.

Neatly enough, in conversation with Carmichael, the gender dysmorphia becomes even more befuddling. Carmichael will play Casanova, as scripted by the poet Carol Ann Duffy, with her company Told By an Idiot at the West Yorkshire Playhouse. “Neil asked, ‘So what are you stuffing down your pants?’ ” Carmichael recalls, chuckling heartily. “But I told him, ‘I’m not dressing up as a man. I’m a woman’.” A woman Casanova? “I think so, yes. It’s all a bit confusing.”

Carmichael has long been an actress of protean parts. “I’ve played a man before – Lorca in I Weep at My Piano – but as an actor you do sort of lose your sex. You put on a wig and run around telling the story however you can, being a queen or a tree or whatever. That’s the kind of theatre we do, anyway.”

Bartlett agrees: “Playing a gender is an extension of playing a character. The casting is not my big directorial idea. Twelfth Nightis a genuinely subversive play and I cast it as creatively as I could from the actors who came to me. My choices are pragmatic, not political. I’m making a very beautiful, fantastically entertaining stage play, not a statement.”

But surely, being blind to gender is something of a statement, isn’t it? Bartlett smiles warmly and leans conspiratorially across the table. “OK. I’ll tell you what I think is interesting: if a theatre company announced that Shakespeare’s Antony was going to be played by a woman, everyone would want to know why. It was written for a man, they’d say, by one of the greatest playwrights who ever lived. But if Cleopatra is played by a woman, nobody thinks to say, but that role was written for a man, by one of the greatest playwrights who ever lived. Yet those are the facts. So we shouldn’t ask ‘Why cross cast?’; what we should really be asking is ‘Why not?’.”

— Twelfth Night is at the Courtyard Theatre, Stratford-upon-Avon from August 30. Tel: 0844 8001110. Casanova is at the West Yorkshire Playhouse, Leeds, from September 7. Tel: 0113-213 7700.

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