Betrayal at the National - Lyttelton

It's a sordid business, extra-marital sex. Especially when you discover your wife and your best mate have been bonking away in a North London bedsit these past five years. Worse still, is the realisation that your young son is probably not even yours, but in all likelihood is the product of an illicit coupling between the duplicitous lovers.

That's the harsh truth that comes home to haughty-but-nice publisher Robert (Anthony Calf) in Betrayal, Harold Pinter's one-act play about a middle-class love triangle. This being Pinter, the action soon degenerates into convoluted web of deceit: Robert feels betrayed by his gallery-owning wife Emma (Imogen Stubbs), but more so by Jerry (Douglas Hodge) because he's always preferred him to his wife. Jerry feels betrayed by Robert because he didn't let on that he had knowledge of the affair. And Emma feels betrayed by Robert, because of his chummy, squash-and-booze friendship with Jerry.

Trevor Nunn's elegant production bears comparison with Patrick Marber's Closer, not least because the decorous Ms Stubbs acted as an adulteress in that too. Both plays nicely point out how insecurities can surface in relationships, even apparently stable ones.

Yet what gives Betrayal an added dimension is the way it employs a topsy-turvy narrative, starting in 1998 with Jerry and Emma discussing their defunct relationship over drinks, and ending with the genesis of their affair in 1989.

At times, much of the heartbreak the characters experience is left unspoken, and as a result the play comes across as a study of internalised emotions and guarded body language - Emma trembling on the bed as Robert uncovers her affair; Robert choosing to gulp down the Corvo Bianco rather than confront likeable literary agent, Jerry. And there are the classic Pinter speech patterns of long......meaningful...... pauses followed by nervy, quick-fire conversational tennis which, ironically, announces little but reveals much in its subtext.

Betrayal's internecine wranglings play out against Es Devlin's stunning set, a reverse mould of seven different interiors, influenced by sculptor Rachael Whiteread's poured concrete house. The greyness of the walls nicely shows up the dates and images, back-projected to suggest periods and locations. And the furniture shuttles back and forth swiftly on a conveyor belt.

The thing is, it's the play itself that seems to pass by swiftly, too. At one-and-a-half hours, Betrayal feels like it's over before it's had a chance to take off, and that there is a need to come back for a second act. Or maybe that's just the effect that Pinter's hugely involving, touching slice of realism has on the viewer.

Richard Forrest