Benedict Cumberbatch has recently played to millions in a five-part BBC serial, The Last Enemy. In it, he portrayed an intelligent, sensitive, educated man who returns from abroad to an England that appears, superficially, to be as it always was, but turns out to be a society collapsing into madness, murder and paranoia, where nothing is as it seems in the surveillance state. He was brilliant.

Cumberbatch is now playing to a few thousand at the Royal Court. He takes the part of an intelligent, sensitive man who loses his job in the City, and whose inner life collapses; nothing is as it seems. The scale is different. In Martin Crimp’s play for three adults and a child, there are no hidden cameras, computer screens, skyscrapers and armoured police, no politicians or assassins, but there is the same feeling of being above an abyss. Cumberbatch is brilliant, as are Hattie Morahan and Amanda Hale.

Neither Crimp nor his director, Katie Mitchell, is known for making things easy, but here there is a plot that can be summarised and a production that seems naturalistic.

There is nothing too unusual about the man’s middle-class milieu, his pretty translator wife (Morahan) or even the slightly odd neighbour (Hale), a nurse whose husband is an army doctor. Except that these superficial realities don’t compute.

The play opens in classic ordinariness: husband comes home from the office; he and wife discuss their day, and somehow talk past each other. She had a strange encounter at the railway station. The politics at his office are bad. She has been given a diary. His prospects aren’t looking good. Only the two sets of shadows on the walls suggest the deep separation between them.

Yet, though there is something destructive in business life, especially when a man loses his job, and with it his sense of identity, this is not the City Crimp has in mind. A second city is evoked, somewhere like Fallujah, when the nervous neighbour describes what her husband has seen on active service, which is enough to make anyone jumpy.

This is not the City of Crimp’s title either, though. That appears only at the end, when two other metaphors carefully hidden on the text’s surface reveal their deeper meaning. The translator is in contact with writers - the strange encounter at the station, for example - people who can transform their suffering into fiction. But she cannot write, only translate. The nurse has a seemingly inconsequential introductory speech about being technically able to play the piano, yet unable to make music. Neither connects.

Absolutely nothing in the text is without purpose, not even the daughter’s innocently obscene limerick. Using a minimalist design by Vicki Mortimer and an unsettling sound-scape by Gareth Fry, Mitchell fine-tunes every twitch of the body language and exactly calculates the distance needed between husband and wife to show they are coming apart. This perfect naturalism, however, is at the service of a more profound unreality, of Magritte-like moments when the cast move in slow motion or the child enters, her clothes identical to the neighbour’s.

In the end, as we learn from the contents of the diary so inconsequentially introduced, the City is a city of the mind, a place of the imagination that is as broken and bereft as Fallujah, itself an emblem of the commercial warfare that is business life. It is as though these ordinary, average people and the normal, conventional world they inhabit share some deep moral stain. In 90 minutes of theatre, The City achieves what it takes five hours of television drama to do.

In the final scene, the child plays her party piece on the piano. It is familiar: it has been overheard from the neighbour’s flat. She goes wrong, starts again. She falters, stops again. The curtain falls. With this incompletion, the sense of desolation is made complete.

Jerwood, Royal Court, SW1

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