I suppose there always was a strong chance that Toby Gough's much-publicised production of Macbeth would crack up under the strain of its own celebrity; and crack up it has, although not quite in the way some predicted. Co-produced by the Holders Season of Barbados, the show bursts garishly out of the darkness of the gardens clutching at least four different production ideas to its chest, and lets them fight it out like ferrets in a sack until the crudest one wins. There's Macbeth the gangster movie, with King Duncan and his boys as cool dudes in big checked flares. There's Macbeth the sexy'n'satanic supernatural thriller, with a touch of pure porn. And there's Macbeth the Carry On film, all sexy nurses and silly voices; although even that doesn't explain the giant, distorted 12-foot puppets who invade the pitch in the final minute of the show.

What's tantalising, though, is that Gough's Macbeth clearly didn't have to be like this. Dannii Minogue may not be the most subtle Lady Macbeth; she's certainly the first to invite the doomed Duncan to snort a line of cocaine from her perfectly-toned thigh. But her performance -darting around in a shimmering emerald shift, supported by a team of murky familiars, devouring drugs, wine and sado- masochistic sex with a voracious leer - is well within the great "wicked lady" tradition of the role. She grasps the essentials of the relationship with Macbeth, uses her body with terrific, uninhibited flexibility and is fearless about the erotic content of the play; and opposite her, Ade Sapara is a solid, pensive Macbeth with a fine voice. But from the moment the great Sleepwalking Scene is played out of sequence and for pure laughs, Toby Gough seems to decide to trash the whole dramatic potential of his production. The second half of the text is mutilated into moral nonsense and the show makes a rapid descent into sniggering, reductive kitsch; decadence, darling, and it ain't divine.

THERE was no vaseline-smeared body suit and no walk-out by the leading lady. That dress, a bottle green, PVC-bodiced Marilyn number designed by supermodel Jodie Kidd, had a starring role. Contrary to wilder rumour, Dannii Minogue kept her clothes on. Whether she kept her dignity, as Journey to Macbeth opened on Friday night at Edinburgh's Royal Botanic Garden, is more debatable. The evening had an air of the surreal from the off. Getting into the gardens was like entering some US military compound.

Ushers lurked in the foliage to stop the paying public straying from the paths. An attempt to guard the Botanics' rare species or protection for a more precious flower?

As it turned out, the paying public had plenty of time to inspect the shrubbery. At last, half an hour late, a piper led the audience to the stage. Even then, they had to wait as a spokesman made clear that taking pictures was forbidden. There had been an "incident" the night before, to which the police had been called.

So it began: Act One, the court of King Duncan. Except, in this kitsch semi-musical version, he has become 1970s Mafia boss Duncan, an Al Pacino impersonator whose court could have come straight out of Studio 54, with Macbeth (Ade Sapara) sporting a Samuel L Jackson hairdo. There were three splendid stilt-walking witches and a score of extras with little to do except shamelessly mug.

Yet something was missing, and not just the choreography. Act Two: her husband installed as Thane of Cawdor, enter Lady Macbeth. Minogue bounded onto the stage like an Olympic gymnast about to do the floor exercises, followed by what appeared to be three members of Pan's People.

Macbeth had left a message on her answerphone, and it sent her into a frenzy of twirls. This was less like floor exercises than rhythmic gymnastics. All that was missing was the ribbon and hoop.

Interviewed in today's Scotland on Sunday, Minogue has said, "when I read the play the sexuality jumped out at me". She has taken it to heart. Launching into the famous "unsex me now" speech, the 27-year- old former soap star fondled her breasts. The problem is that - whether grabbing Macbeth's crotch or eating an apple - the effect is more comic than erotic, a teen magazine idea of a woman's wiles.

Yet to place the blame for this disastrous school play on its star alone would be unfair. Self-indulgent, technically bedevilled and poorly acted, Toby Gough's production treats its audience with contempt. It has neither the courage to let Shakespeare's text speak for itself nor to dispense with it.

At its best, it's simply sloppy; at its worst - when Minogue is allowed to upstage Macbeth's dagger speech by tipping candle wax onto a masked man -it is a travesty that will sacrifice any dramatic tension for a cheap thrill.