British cheek

Film - Playing a 1940s Soho stripper unleashed the exhibitionist in Sarah Solemani

''There's nudity, but it's tasteful. And Judi Dench is in it," Stephen Frears explained over coffee. I nodded back eagerly at my favourite British film-maker. "That's fine, I'll do it." He continued slowly, sounding strangely as if he might be persuading himself. "I mean, you'll look like a painting - and it's a beautiful story." "No, honestly, you don't have to go on. I'm very comfortable with my body. In fact, I'm much better naked than with clothes on. When's it set, 1930s-40s? Well that's my body shape! Yes, I'll do it. Definitely. That'll be fine. No problem at all."

It was the standard actress's hustle, and I repeated it to myself a month later as I stood on a plinth, naked under a thin white towel. I had been cast as Vera in Mrs Henderson Presents, a film about an eccentric widow (Judi Dench) who uses her husband's legacy to transform a Soho theatre into the first British nude revue. My role was to recreate the series of tableau poses that the girls, forbidden to move on stage, performed throughout the Second World War to excited crowds at the Windmill Theatre.

Beside me, on plinths of their own, were the other girls, soon to become my friends and comrades: Natalia Tena, Rosalind Halstead and Anna Brewster. We were all in our late teens or early twenties, old enough to be professionally calm, young enough to be physically confident, and female enough to be quietly comparing ourselves to each other. We had been plucked, preened, sprayed and powdered and now, on Frears's formidable cry of "Action!", the towels would have to go.

My enthusiasm during the meeting with Frears had been genuine, but now concerns sprouted beneath my stiffly sprayed curls. Would this come back to haunt me? What would my professors say? Had I become merely a diluted expression of the female form, prostituting myself by commodifying my naked self? Was that third croissant a mistake?

The Windmill's manager, Vivian Van Damm (played by Bob Hoskins), would allay the girls' trepidation with the mantra "You are artists", which we soon adopted for ourselves. The nudity became normal and the theatre, built inside Shepperton Studios, became our home. The original Windmill girls were made to feel liberated: they were cultivators of beauty, not smutty pin-ups. We, too, were treated like artists, and we smoked cigarettes as our nipples were rouged and dipped spoons in each other's desserts, committed to the "no-gym" law announced by the producer Norma Heyman. She insisted that we remain faithful to the body shapes of the era: soft, not muscular, and oblivious to protein shakes and carbohydrate phobias. I work in a field where being a size 12 rarely brings casting advantages, so this was music to my ears.

Mrs Henderson defended the Windmill as a service to young men setting off to war, arguing that each soldier deserved to see a naked woman before he died. It is doubtful that the argument would have convinced, had she not been 70 years old and an unashamed aristocrat. Nevertheless, she was a provocatrice rather than a pornographer, and it was essentially her commitment to good taste that led to the Windmill's demise. As the laws changed, the strip-club revolution began and tab-leau shows became a thing of the past.

Did I feel liberated, having been naked every day for ten weeks? Not really. Female exhibitionism and liberation are often and conveniently confused. Standing still with no clothes on is not liberating, because it's just standing still with no clothes on. We were passive in front of the camera and had entirely to trust Stephen's taste and skill.

One evening, however, on the motorway home after filming, Natalia and I noticed a car driving Christopher Guest, who played the supremely straight-faced Lord Cromer. We had all shot a scene together and he was going back to LA. A quick mischievous look followed by a nod of agreement was all it took: we whipped out our bums - fleshy, white and gym-free - and pressed them to the window, filling up the pane like soft dough. Christopher and his driver passed, laughing. We had sent him off with some true British cheek, and cackled for the rest of the ride home. It was harmless, it was safe, it was a little bit sexy. It felt like it might have been liberation. It even felt as though it might have been the kind of liberation Mrs Henderson herself would have praised. And, actually, it felt rather good.

Mrs Henderson Presents (12A) is released on 25 November