The guilty conscience

He is on an obsessive mission to hunt down the killer of his wife. But the man he is pursuing turns out to be himself. He used to be an insurance investigator whose job was to uncover fraud. But should he be on the receiving end of his own professional scepticism? Is his mental condition – a chronic short-term memory loss since the night of the tragedy – a suspect psychological insurance policy? Now, to keep track of what has just happened, he has to resort to Polaroid photographs, scribbled notes, and (an extreme form of insurance) tattoos indelibly inscribed on his body. His story is told backwards, in overlapping recapitulations that initially perplex (making you empathise with his brain-damaged difficulties) and then force you to reinterpret what you have already seen.

He is on an obsessive mission to hunt down the killer of his wife. But the man he is pursuing turns out to be himself. He used to be an insurance investigator whose job was to uncover fraud. But should he be on the receiving end of his own professional scepticism? Is his mental condition – a chronic short-term memory loss since the night of the tragedy – a suspect psychological insurance policy? Now, to keep track of what has just happened, he has to resort to Polaroid photographs, scribbled notes, and (an extreme form of insurance) tattoos indelibly inscribed on his body. His story is told backwards, in overlapping recapitulations that initially perplex (making you empathise with his brain-damaged difficulties) and then force you to reinterpret what you have already seen.

This is the predicament of Leonard Shelby, the protagonist of Christopher Nolan's brilliant neo-noir movie, Memento. Cinema buffs have rightly placed the film in the tradition of Double Indemnity (which also begins at the end and turns on an insurance investigation) and Point Blank. But there's another work of art with which Memento has remarkable – yet oddly unremarked – affinities, and it's about two and half thousand years older than the movie parallels: that primal Greek tragedy, Oedipus Rex.

Sophocles' hero is, after all, the archetypal case of the investigator hunting down a criminal who proves to be fatally close to home. The play, likewise, begins at the end and unwinds through a reverse-order revelation of his past, rising to a climax when the fatal facts of his infancy are disclosed. In addition to providing Freud with the mythic basis of his famous "complex", and Aristotle with his template for the perfect tragedy, it's worth remembering that Oedipus Rex is (as Peter Hall once remarked) "the first thriller". And the influence of the play is so deep and pervasive in our culture that it's not only in direct adaptations (by artists ranging from Kleist to Cocteau, Stravinsky to Berkoff) that its disturbing features resurface.

Nolan's neo-noir movie and Sophocles' Greek drama share, for example, a fascination with the ironies of attempting to insure against risk. The Oracle that predicts that Oedipus will murder his father and marry his mother dangles the treacherous, illusory hope that, thus forewarned, the character will be able to take steps to guard against such deeds. But all these insurance policies backfire. From being a firm believer in divine forecasting, Oedipus is reduced, as proof is nightmarishly piled upon proof, to declaring the Oracle and its prophecies "dead and rotten".

Memento, by contrast, tells the story of a protagonist who begins by over-valuing scepticism. We learn that, in the (real or invented) past, he turned down the insurance claim of a man who, because of an accident, was left with some short-term memory loss. Convinced that this was a psychological reaction rather than an organic condition, the suspicious Leonard refused him compensation on the grounds that his client was not covered for mental illness. Now, with savage irony, Leonard's suppressed dread is that he himself is the real fraud – his recurrent obliviousness an insurance policy against facing the truth. As his one dubious crony remarks: "You're an insurance investigator – maybe you should start investigating yourself..." It's this preoccupation with the terror of losing one's protection plan that gives the film a depth unmatched by Spielberg's Minority Report, in which Oracle-like "pre-cogs" dream of murders-to-come, and Tom Cruise, as the top man in the Pre-Crime department, has to fight to escape destiny when he becomes his own chief suspect.

In Nolan's movie, the "facts" are tattooed on Leonard's chest in mirror-writing so that he can read their reflection. Memento is itself a kind of reverse-image of Sophocles' play: instead of building up to a moment of horrified recognition, it climaxes on the moment when the emotionally cornered hero chooses denial. Repression, though, is also a creepy feature of Oedipus Rex. As the theatre director Nicholas Wright has suggested, there is something perverse about the way the investigative hero keeps asking questions, even though the disastrous deduction is staring him in the face: "Is it because he is purely a function: that pitting himself against a forbidden truth is all he can do? Alternatively: has he repressed the information? This is the crucial choice for anyone playing him. Has Oedipus a subconscious?"

Opening at the Rosemary Branch Theatre in Islington, north London, at the end of this month, where it will play in a double bill with the Sophocles original, Jeremy Kingston's excellent new play, Oedipus at the Crossroads, proposes a startling and novel reason why the hero so obligingly asks all the right (so to speak) wrong questions, thus doing the gods' dirty work for them in becoming his own destroyer. The solution is simple and outrageous: it wasn't Oedipus at all, but a compliant stand-in sent to Thebes in place of the real hero, who had spiritedly rebelled against the scenario mapped out for him.

If Memento is a tribute to the powerful subterranean effect of Sophocles' tragedy, Oedipus at the Crossroads is a delightfully witty and incisive testimony to its enduring capacity to provoke dissent – a tradition that stretches back (at least) to Voltaire. Kingston (who is also a fellow critic) dramatises an artfully rewritten back-story to the Greek original. Arriving at the place where three roads meet, Sophocles' hero had killed an angry old man in a chariot who almost ran him down. It's only much later that he discovers that this was his father, Laius. Kingston's hero, by contrast, kills one of Laius's young soldiers, and when he is about to be repaid in kind, blurts out that his death (before murdering his father or marrying his mother) will at least disprove the Oracle. This reveals his identity to the shocked Laius.

In Sophocles' day, there may have been scepticism about individual false prophets, but Oedipus Rex amounts to a horrifying affirmation of the principle of oracular divine prophecy. What mischievously emerges in Oedipus at the Crossroads is that the hero's fate has, in fact, been minutely stage-managed not by the gods but by human agency – a self-interested network of fraudulent priests who want to shore up faith in the Oracle in order to preserve their power as interpreters. When the dissident hero refuses to bolster this dubious ideology, a willing imposter steps into the role. At the end of Kingston's bracingly humanist drama, you have the queasy sense that, on some other stage, Sophocles' tragedy will eventually unfold exactly according to plan, but as a hollow piece of clerical propaganda, a sham emptied of any spiritual meaning.

This double bill is not the first time that Oedipus Rex has been staged with an irreverent companion piece. Recently, Barrie Rutter and Northern Broadsides ran the original in rep with The Cracked Pot, Kleist's 1806 comedy that reinvents the hero as a corrupt Dutch village magistrate who presides over a court case where the guilt that steadily emerges is his own. The key farcical difference is that Oedipus is unconscious of his crime, while Kleist's cloven-footed sexual blackmailer is all too aware that he must orchestrate a cover-up. But the new diptych at the Rosemary Branch Theatre is surely the first occasion on which Oedipus Rex has been coupled with an outright riposte.

Not that Kingston's play implies that Sophocles' tragedy has fundamentally dated – for every age has its version of Fate and its own idea of what constitutes freedom. Instead of gods and oracles, we have genes, genetic predictions and a fresh set of fiendish insurance problems. It can't be long before someone updates Oedipus Rex to the world of genetic engineering and designer babies, with the hero now featuring as, say, the screened and rejected embryo who winds up in a different womb from his mother's... The myth is inexhaustible. I hope to return to the subject later this year when Peter Brook's theatre, the Bouffes du Nord in Paris, mounts Sotigui Kouyate's Oedipe, an adaptation that will explore many diverse approaches (psychoanalytic, historical, artistic, critical) to Sophocles' play and offer (to coin a collective noun for its hero) a complex of Oedipuses.

'Oedipus Rex' and 'Oedipus at the Crossroads' open at the Rosemary Branch Theatre, 2 Shepperton Road, London N1 (020-7704 6665) on 28 Jan