What is it about men pretending to be women that makes us laugh so much? Why isn't it funny the other way round? Should women take it as insult or a tribute? Such were my thoughts over the stretches of time that I, personally, wasn't shaking with mirth during the opening night of Les Ballets Trockadero de Monte Carlo. But to judge by the uproarious mood of the Peacock's dress circle, I was alone in my musings.

The Trocks, as they like to be known, are a troupe of travesty ballerinas who perform excerpts from well-known classical repertoire. Let's face it, they picked an easy target. I challenge even the most devoted balletomane to swear that they have never suppressed a snigger over a third-rate production of a Russian classic. Ballet is an art, an artifice, that treads the fine line between the ethereal and the absurd. Dress a line of men in tutus, and you'll get a laugh for nothing. Have them flap about in dodgy arabesque as swans, and you bring the house down. For a while.

The real skill of the Trocks is that they overlay the cruder gags (toppling off-point, falling A-over-T) with detailed observation of ballet's subtler foibles and potential for stylistic mishap. There's the ballerina who, partnered by a short-arsed cavalier, has to duck his supporting arm on each revolve of her otherwise pristine pirouette. The stage-struck Odette who cannot resist mugging at the audience between each tragic pose. The Prozac-popping Esmeralda, whose coy dejection renders her incapable of rattling the obligatory tambourine.

For spectators in the know, sly digs at historical context ground the flimsier jokes in truth. The very name of the troupe is a reference to the many reincarnations of Diaghilev's Ballets Russes, with its trend- setting stars and their invented Russian stage names. Ida Nevaseyneva ("former arsonist-in-residence at the Kirov"), Igor Slowpokin ("awarded the Short Order of Lenin for his exquisite partnering technique"): they get a lot of mileage out of this.

Almost all the visual gags work on two levels. While non- cognoscenti groan at the wooden swan being towed across the stage because it's naff, balletomanes are whooping, because they've all seen Soviet productions in which that happens in earnest.

Cleverest of all is the two-and-a-half-minute parody of Fokine's "Ze Dyink Shvon" in which a conk-nosed Pavlova bourrees on stage shedding more feathers than a cheap quilt. Halfway through her quivering decline, the extraordinary rippling arms and elegant feet subside into a bad case of turkey neck and splayed knees. She eventually gives up and keels over - a genuine terminal fowl.

The finale, Paquita, brings on the entire 14-man cast in all their glory: immaculate mauve tutus, gorgeous legs and clean balletic line. After five minutes, the realisation dawns that you are watching unadulterated 19th- century ballet without an upended bum in sight. As you'd suspected, the burlesque is merely an excuse for these guys to embrace all the best roles and dance their hearts out, which they do with considerable grace as well as muscular vigour.

The management have persuaded Darcey Bussell to come on at the end to deliver bouquets, which underlined the obvious conclusion: that the Trocks are really just a bunch of Darcey wannabes, and no less watchable for that.

Peacock Theatre, WC2 (0171 314 8800), to 28 Sept.