This is the first important revival of a piece disgracefully undervalued when it appeared 13 years ago. Harold Pinter has admittedly written more forcefully; but none of his plays, not even The Caretaker or Old Times, has the emotional density of Betrayal. As David Leveauxs wary production confirms, there is hardly a line into which desire, pain, alarm, sorrow, rage or some kind of blend of feelings has not been compressed like volatile gas in a cylinder less stable than it looks. What upset the reviewers in 1978 was subject matter that seemed annoyingly futuristic. The plot harked back to a theatrical period when dramatists were obsessed by love-triangles which, if not eternal, were certainly interminable. Yet since the story started after a man’s affair with his best friends wife had finished, ended with its beginning, and in between lopped this way and that through time, Betrayal was also dismissed as gimmicky. The answer is that Pinter’s narrative method takes "what next?" out of the spectator’s mind and replaces it with the rather deeper "how?" and "why?". Why did love pass How did these people cope with the lies, the evasions, the sudden dangers, the panic, and the contradictory feelings behind their own deftly engineered masks? The play’s subject is not sex, not even adultery, but the politics of betrayal and the damage it inflicts on all involved. Even by Pinter’s standards, those politics become pretty intricate. For instance, we learn early on that the old friend, Robert, has known for years of his wife Emma’s affair. She knows he knows, but her lover Jerry does not know he knows or that she know he knows. See what I mean? A lunch between the two men, Jerry fake-innocently asking after Emma, Robert seeing through the ruse yet humouring him, seethes with unexpressed guilt and anger. Almost all the play’s encounters are similarly charged. It is like watching Kasparov circle Karpov’s queen, not knowing when, how or if he will pounce.