IN IRVINE WELSH'S first stage play, a four-hander which premiered last week at West Yorkshire Playhouse, the Trainspotting author goes so far out of his way to taunt us that one recoils from recoiling. He wants us to have a bad time. Horrible scenes are horrible to watch. Grim and cruel, You'll Have Had Your Hole gives sex and violence a bad name. Which makes this nightmare evening an oddly moral play.

In You'll Have Had Your Hole, two small-time crooks take another crook hostage in a disused recording studio somewhere in a Scottish city. In this sound-proof building, they torture, rape and drug him. He dies. One captor then turns the other captor into a prisoner. Blackout.

Pity the guy who gets cast as the hostage Dex. He spends the play trussed up in a harness that is hoisted up and down on a pulley. His legs are bound, his head strapped in and his mouth gagged. Billy McElhaney plays him with the bruised anger of a boxer who discovers he's a punchbag. His captors subject him to a numbing range of physical and psychological abuse, from facetiously playing Engelbert Humperdinck at top volume through his headphones to anal rape.

His captors are an odd couple. The heterosexual one, Docksey, played with thin-faced, feral persuasiveness by Malcolm Shields, goes to the flat of Dex's girlfriend, Laney, and seduces her. Luckily for him, Laney is an ex-hotel receptionist who has hung on to her talent for being receptive. This is because she has zilch character. Indeed she's a frontrunner for this year's slimmest role written for a woman by a man. (But these are early days, and the competition is always tough.) As the accommodating Laney, Kirsty Mitchell looks way too nice and middle-class for this lot.

After sex with Laney, Docksey swallows the bedside glass of water in which Laney has put her contact lenses. In Trainspotting, the hero had to dive into a murky loo to retrieve some pills. Here, Docksey has to wait till he defecates before he can give Laney back her lenses. We know Welsh has a thing about shit. In this shoddily conceived piece, what was once a thematic preoccupation is becoming perilously close to qualitative judgement.

Docksey and Dex once teamed up to murder the same guy, and Docksey is fascinated by Dex's lack of remorse. He wants to torture some feelings out of him. Thanks to meeting Laney, however, he develops delicate feelings of his own. As the other captor, the bald, willowy, gum-chewing, nitrate-sniffing Jinks, Tam Dean Burn gives a feverishly malign and limp-wristed performance. After he fulfils his early promise and finally rapes Dex ("Here comes the choo-choo"), Jinks informs Dex that he has Aids.

Ian Brown's uneven production has the same trouble switching between the noisy high-tech resources of the recording studio and the rhythms of the dialogue as Welsh has switching between genres. Welsh can't compete with Ben Elton or Patrick Marber - two other male authors presented at Leeds this spring - in terms of basic dramatic skills. A grisly mix of black humour, mock-Jacobean violence and Mills & Boon romance, the smartest decision in this 90-minute play is not to have an interval. The programme carries a rallying foreword by artistic director Jude Kelly - enlisting DH Lawrence, John Osborne and Joe Orton - that explains that, in Welsh's play, "a new, uncensored moral landscape comes into view. And we are free to explore it." Roughly translated, this means it's hip, nasty and pretty confused. An international tour of this production is sponsored by the British Arts Council. The scenes I'd like to witness are the post-performance receptions for local VIPs.

After a fairly average opening storm, with billowing blue sheets, a model ship bobbing up and down and actors swaying from side to side, Adrian Noble's production of The Tempest calms down - and simultaneously livens up. This is the first time the RSC's artistic director has done The Tempest and his dream-like production is fresh, lucid and authoritative: a clear and satisfying development, in terms of how to use the Stratford main stage, from last year's Cymbeline. Anthony Ward's designs beautifully combine textural depth with visual simplicity. As with Cymbeline, there's a central circle and a catwalk that runs from the stage deep into the heart of the stalls, an umbilical cord between actors and audiences that pulls us in and allows for striking entrances.

The cast are strong too. A cloud-filled scrim pulls back to reveal David Calder standing on a pebbled island. His robe trails back to become the huge sheet that forms the backdrop. Calder is a proud, unsentimental Prospero - a man with a tempest within that needs assuaging. "I am ready now," says Calder, and Noble's production sustains this immediacy and imminence. Penny Layden is frank and natural as the barefooted Miranda. Robert Glenister's growling and crouching Caliban hasn't blacked up. He's greyed up. He has bandaged hands and feet and a collar round his neck with only the whites of his eyes showing. He first appears after he has delivered his first line from within a large conch shell. The Neapolitan courtiers, who wear Elizabethan finery - smoothies in ruffs, you might say - aren't as eye- catching as their costumes. Nor is Evroy Deer's headstrong Ferdinand wholly convincing. But Adrian Schiller brings a mischievous earnestness to his dark-eyed Trinculo. He is a definite comic talent who can take time over a line because he turns it into an heroic struggle of intellectual endeavour.

Further up the road in Stratford, director John Crowley brings together three one-act Irish plays as an uninterrupted "trinity" called Shadows. Two are by JM Synge. In the plangent Riders to the Sea, a mother loses the last of her seven sons when he also drowns. In the very funny Shadow of the Glen, a husband only pretends to be dead. The last one is by Yeats. In the haunting Purgatory, which has the Beckettian setting of a ruined house with a barren tree, a father who has killed his father now kills his son. The three pieces work well together. The linking theme is the shadowy, constant relationship between the living and dead. Crowley handles this commerce between the two worlds with a marvellously sure sense of tone. The traverse staging on a wooden floor is pure, uncluttered and atmospheric. His cast of six play 12 characters as if they were 12 actors. Humane, tender and funny, Shadows is the perfect antidote to the sensationalism of the chemical generation.

'You'll Have Had Your Hole': Leeds W Yorks Playhouse (0113 213 7700), to 21 Mar. 'The Tempest' & 'Shadows': Stratford RSC (01789 295623), to 4 Sept.