If it's an appropriate response to Prince's juicy lyrics stick on a video of His Purple Highness

If it's an appropriate response to Prince's juicy lyrics, stick on a video of His Purple Highness himself.Royal Festival Hall, SE1 (0171 960 4242), to Sun 8 Sept.. It Was hardly The Mousetrap. The original Star Treks were all made in a three-year period (1966-69), and only 79 of them were transmitted. Yet as a cultural reference point - a "common conversation" - Star Trek is perhaps the most influential TV series ever shot. Dramatically slack, the piece was as empty as the dancer's discarded clothes and, frankly, I was embarrassed If it's ballet you fancy, hie thee to a ballet. I hope we were meant to snigger at "I Want to Melt with U" - an erotic underworld in which a girl in a gold bra tickles a branding iron over the sensitive parts of various blokes in orange wigs while the chorus simulates urgent copulation.But we were certainly meant to keep a straight face during "Purple Rain", a melodramatic solo in the mould of Pierrot Lunaire, even when the desperate clownette stepped out of her costume and got hoisted like a dead Christ onto the shoulders of a pack of hunky dudes.

Billboards protests too much.With appalling aptness the Laura Dean piece ends with the company falling flat on their faces. As indeed do the three other choreographers who contribute to this unholy hybrid - Charles Moulton, Margo Sappington and Peter Pucci. Or, if we're talking rock-cred, then in Ashley Page's bit of rough in Fearful Symmetries set to John Adams ... or Christopher Bruce's Rooster that makes hay with the Rolling Stones.

The tragedy is that American audiences apparently need this underlined in red. Dance-followers in Britain will know that there was more sex in Kenneth MacMillan's big toenail than there is in the whole of Las Vegas. The piece groans under a frenzy of false ecstasy, like a teenage party that's been allowed to go on too long. What it's trying to prove of course is that ballet can be fun, sassy and sexy. I've seen better.As Prince (on tape) reaches his umpteenth climax, the dancers join hands to whoop their way through an Okey Cokey of high-school aerobics - Pan's People meet the Kids from Fame. You thought ballet dancers were sissy? bellows Laura Dean's choreography - then get this. Pairs of girls pirouette prettily on pointe to meet each other then erupt in a raucous bump'n'grind routine.

The boys launch an offensive of extreme balletic leaps and mid-air splits. Who can jump the highest, the furthest, the fastest? But if this is the ballet Olympics, no one deserves a medal. For trash it is from start to finish - of the emptiest, tinniest, most readily discardable kind.As Prince's "Sometimes it Snows in April" sets up its virile disco thump, rhinestone-twinkly girls and boys get up on their toes and archly parade their wares. It's American for those huge adverts they have by the side of the road "Ah voila," she came back "That fits It is saying two dimensions It is saying popular. And it's saying it wants very much to sell something." Got it in three, Michele.