PERFORMANCE ART / Best seat in the house?: Rose English's new show involves a live horse. But can she really ride? Rosie Millard found out

'I THINK I need help getting on this horse,' said the performance artist and self-appointed showgirl Rose English. 'I've not done very much riding before,' she continued as she clambered up the mounting block and on to a solid-looking black steed. 'He's called Magic? How wonderfully appropriate.'

And not simply because, practically speaking, English's equestrian skills could do with some magic to bring them up to even basic pony-trekking level. Magic and horses also come together in her new show, My Mathematics, which transfers to the South Bank next month after a run on Broadway. It's a show about performing horses and, yes, involves bringing a live performing horse on to the stage of the Queen Elizabeth Hall. 'I've got one for the show in New York, and one for London. They were very carefully selected: I chose two horses I could communicate with silently, and who looked like they could have an ability to, well, hang out.'

Devotees of English's work - ever weird as it is - will not be surprised that she has requested horses which can 'hang out': her work, which appears every two years or so, marries balletic choreography with wry observations about life. Her idiosyncratic performances have been startling the club and fringe theatre circuit for more than 10 years.

Past appearances have involved her, clad in a ball dress, working with Olympic ice-skaters on a rink in the middle of the Royal Court Theatre (The Double Wedding), and requesting members of the audience at the Gate Theatre, Notting Hill to come and sit on her lap (The Beloved). But for all her outrageousness, the graciousness of her manner and the longevity of her service have earned her the nickname of 'the Queen Mother of performance art' among fans. In the recent English National Opera production of Die Fledermaus she was invited on stage for a two-minute slot as a feathered and sequinned personification of champagne; it was this experience that made English realise she and horses were meant to be.

'I suddenly realised I had this kind of showgirl persona. I don't know where it came from, but once I had the outfit on, I thought this won't be coming off for a few years. There was this pony in the production and every time I walked past him he got frightfully interested in my plumed head-dress . . .' She broke off to do battle with Magic's reins. 'So I decided to do a show which looks at the heroic presence of the performing horse, and our relationship with them.'

My Mathematics tells the story of Rosita Clavell, an archetypal showgirl whose variety act used to contain a troupe of horses and an entire orchestra. The play finds Rosita many years on, still performing, but with her entourage stripped down to one horse, one accordion player and a pile of memories. The action involves various equestrian stunts, and taped arias from a Bulgarian female choir singing along to the accordion. The American horse has a different repertoire from its British counterpart, so there are two different versions of the show. 'Luckily, they both like the accordion,' said English.

'Can we canter?' she suddenly inquired. 'I do find it so exhilarating. I'll just hold on with my knees. Am I confident? I'm in heaven.' She careered off down a dusty track on Wimbledon Common. When we returned to a walk, English - fortunately still carried by Magic - said she believed that My Mathematics summoned up the spirit of man's oldest transport system far more realistically than her previous equestrian attempt: 'Many years ago I presented a show done by six dancers dressed as horses, in a dressage arena. They had small tails and shoes which looked like hooves. But I've moved on since then.'

Rosita's show has been drastically cut in resources: My Mathematics asks if something can be pared down to the bare minimum. 'I'm interested in the idea of whether a show can be reduced to a basic formula. Sometimes, as in thrillers, the formula can be wonderful, and a writer can spend his whole life exploring it. But it can also be a tyranny. If the formula is rich, it can be entrancing, but even with avant-garde work, it can become boring. Knowing the moment to abandon a formula is very important.'

English's work demonstrates how the formulaic can still inspire originality. 'An early source of theatrical inspiration was the Royal Tournament,' she says. 'With an Army childhood, it was the first spectacular event I ever saw. I particularly liked the 'March of the Gun Carriages', which was like a military version of the Lido routine. Since I was taken as a child, I've never been able to choreograph anything that's asymmetrical. It was a major influence on me.'

Rose's own forthcoming spectacle, in which she wears six-foot-long false eyelashes made from peacock feathers, a sequinned leotard and fishnet tights, will come straight from New York to London for just one night. The pirouetting horse will have a special dressing-room at the back of the stage, and a stable in the South Bank Centre.

Turning into Wimbledon Village Stables, Rose English sighed. 'I've got to really explore being on horses, rather than alongside them. But I'll have to work on it. Vaulting on to horses is really popular now,' she said longingly. 'Perhaps I could learn. The trick I really want to do is the one I have seen where this woman rides side-saddle and jumps over tables of glass and china. The horse rears up and she leans back, her hair streaking back down its tail.' The staff of the riding school looked at her oddly - before the ride, they had been tempted to put her on a leading rein. 'Maybe I'll just have to settle for having those kind of people on stage with me,' said the showgirl as she dismounted.

My Mathematics is at the Queen Elizabeth Hall, 5 August at 7.45pm (Box-office: 071-928 8800).

(Photographs omitted)