For one moment in the first scene, you wonder whether writer Nina Raine has unexpectedly gone all grand Guignol. Two couples are celebrating a new baby and engaging in banal chat about family, where to site the sofa in the new living room etc., when the conversation turns to “What have you been doing lately?” and suddenly they’re all talking about committing rapes and murders. But no, it transpires that they’re barristers using verbal shorthand to refer to their cases. Matters settle down into that now generally outmoded genre, the “adultery in NW3” play (all right, to be precise NW1).

However, this is an exceptional example of the form and goes much deeper. Unfaithfulness – real, attempted and imagined – amongst these two couples and a third seethes with issues of morality and emotional engagement, nicely contrasted between private and professional lives. Through it all reverberates that title, especially when the one court case we see becomes echoed in the matter of marital rape. Even the non-lawyer character, an actress, is playing Medea.

Raine is such a fine writer that not a moment of it seems contrived, even the bits which obviously are. In one scene, the actress is asking two of the male lawyers for advice on playing a barrister; their explanations about gaining control of the courtroom narrative by tricks of manner, asking “closed” questions and so on, grow more pointed as they illustrate matters by examining each other about their respective secret sexual desires. Yet Raine’s precision as a writer, Roger Michell’s skills as a director and the performances of Ben Chaplin, Pip Carter and Daisy Haggard mean that the fabric of naturalism is never stretched to transparency. Later, Chaplin is also excellent as an almost Aspergically dispassionate advocate dissolving into inarticulacy when he finds himself feelingly embroiled in the kind of situation he has so often tried.

Let me put it this way: this is the kind of play and production in which the renowned and consummate talents of Anna Maxwell Martin (as Chaplin’s character’s vengeful wife) merit little more than a passing mention in the context of everything else that’s going on in terms of acting, writing and discreet direction. A bit of a beaut all round.

Written for the Financial Times.