‘Your sense of detachment is terrifying, lad,” says police officer Truscott admiringly to young Hal, who is blithely reuniting his mother’s corpse with her false teeth and glass eye.

This is after the body has been hidden upside down in a wardrobe, disguised as a tailor’s dummy and very nearly dumped in an unmarked grave. The detachment exemplified by Hal in Loot is the key to the whole of Joe Orton’s brief but explosive career.

Every one of the playwright’s characters is hilariously detached. In the four years before 1967, when he was brutally murdered by his lover, Kenneth Halliwell, Orton created a set of subversively wayward characters who break all the rules.

Some are so beholden to authority that they are detached from reason; others, such as Truscott, are so dizzy with power that they become detached from social responsibility; and the rest, like Hal, are so purposefully amoral that they are detached from any semblance of conventional behaviour.

This is what makes Orton so deliciously, blackly funny, even 40 years on, when our attitudes towards Catholic dogma, homosexuality and general sexual licentiousness have relaxed considerably.

Whether it is corpses or corruption, Orton still has the power to shock us out of our cosy decorum.

Which makes it all the more puzzling that Stephen Wrentmore has chosen to direct Loot as if it were a serious psychological drama. In its own way, Orton’s style is as precise as that of Oscar Wilde, requiring of the actors a complete lack of emotion — ideally to the point of offensiveness. His characters behave out of self-interest and moral indifference — detachment must be their watchword. The problem with this production, which transfers to Perth theatre after its run at St Andrews, is that the characters seem to care.

This does not make sense in a black farce that resembles a warped parody of Hamlet. Hal’s mother has died and is not even in the ground before her gold-digging nurse is trying to marry Hal’s bereaved father. Far from being outraged like the Prince of Denmark, the young man is unconcerned — except that he thinks the nurse would make a better match for his philandering pal Dennis. The death of his mother, lying mummified in her coffin, merely provides him with a handy place to hide the money he and Dennis stole in a bank job. Her loss means nothing to him.

Only a heightened style of performance can make sense of such iconoclasm, but here, especially in the first half, Wrentmore takes it at such a languid pace that the epigrammatic power of Orton’s language is utterly drained away.

This is exacerbated by the actors’ cloth-eared delivery — stresses invariably in the wrong places render potentially hilarious lines peculiar and baroque. The lack of laughter in the auditorium is offset only by our blind hope that there is method in this madness and that an explanation is around the corner.

And to some extent it is. The production gathers momentum as Orton’s distorted logic runs its course, and the actors — notably Tom McGovern as Truscott, Gemma Burns as the nurse and Tom Freeman as Dennis — finally pick up the pace.

But even here Wrentmore interrupts the play’s natural rhythm with his directorial intrusions. Several times he dims the lights to set a speech to music, illustrating a description of a car crash with quirky sound effects as if Orton’s words were not enough to get the point across. Such decoration can add a poetic dimension to a straight play, but imposed on the relentless forward drive and primary colours of Loot, it is self-conscious and distracting.

In his Ortonesque black leather cap, Derek McGhie’s Hal is surly and uncomfortable instead of brassy and carefree, adding to the sense that the company hasn’t really understood what Orton’s anarchic spirit was all about.

Times Recommends

• Milk: do we need a dairy godmother?
• DIY: the women doing it for themselves
• First double portrait of Princes unveiled