It is interestingly weird that Trevor Nunn should be directing his own wife, Imogen Stubbs, in a play about a sexual relationship with a philandering partner, played by Iain Glen, that transcends the difficulty and the aftermath of a civic arrangement.

For the late Ingmar Bergman’s 1981 play, adapted by Joanna Murray-Smith, which was hacked out by the great auteur himself from his own brilliant 1972 film – itself distilled from six half hour television episodes – is nothing if not personal. It reeks of the love that dares not speak its name because it is literally inexpressible.

Johan (Iain Glen) works in psycho technology and Marianne (Imogen Stubbs) is, ironically enough, a divorce lawyer. One of the great scenes in the film, one of the few involving only one of the couple, sees Marianne listening to the “final straw” speech of a pinched and repressed woman who has endured a loveless marriage for twenty years and has decided to leave it.

The great secret of Johan and Marianne is that, despite separating and marrying other partners, their own love is indestructible. The particular density and power of the film is fuelled by Bergman’s own love for Liv Ullman (and hers for him), who played Marianne, and the genius with which Erland Josephson translates Bergman’s obsession into his own personality.

There is no questioning the profound affection between Glen and Stubbs, but it is, of necessity, of a much slighter kind. Their satellite friendships with Dominic Jephcott’s grotesque and fearful Peter and Tilly Blackwood’s svelte and demeaning Katerina only serve to place their own relationship in sharper relief. They cannot live with each other while being unable to survive without somehow trying to.

Nunn’s production in the comfortable new studio at the handsomely rebuilt Belgrade is swift and subtly barbed, played out on an antiseptic white setting by Robert Jones with filmed insets of domestic scenes in other landscapes. The blood and violence of the scene where they decide to prosecute their divorce arrangements is as suddenly shocking as the final descent into a sexual, inevitable intimacy is both moving and strange.

Not as strange, mind you, as it is in the film, where the world seems literally to close over the couple’s heads with the duvet. Glen maintains an amused and charming exterior throughout while Stubbs, quite cleverly, has to convey Marianne’s psychotic impulses in a series of increasingly desperate and comic gestures. The dark heart of Bergman is all that is lacking.

- Michael Coveney