It's a play and film about the tangled stories of a series of couples, each story leading on to the next. In the play these stories unfolded by having two different scenes performed on stage at the same time. So for example, two different couples would be arguing, in two different rooms - but all four actors are on stage at the same time, on the same set of a room, talking together or across each other. The two men might both say 'I'm sorry' at the same time, but in different voices, then the women reply one after the other, in different ways, and one couple reconciles as the other split up. Not every scene is like that, but the whole play develops in that way, the stories echoing each other. The only scenes that did not quite work for me were when the two women were talking together, I don't think he had quite captured the female voice.
The other actors were Ian Hart (non-brits may know him best as Quirinus Quirrell in the first Harry Potter film) Lucy Cohu (who was apparently Alice Carter in Torchwood?) and Kerry Fox (Shallow Grave among many other films). These are middle aged people, and I was pleased that the women were attractive but real-looking.
Here is the Guardian review which I see says that the film Lantana is based on this play not the other way round. Here is how Billington describes the theme of the play.
What Bovell is saying gradually becomes clear: Trust, whether between husband and wife, supposed lovers or therapist and patient, is dismayingly rare; and although we live in a world of hidden connections, we are all sentenced to solitary confinement inside our own skins... I admire Bovell's use of narrative suspense and his ability to suggest that coincidental encounters mask a deep unease.
Unease is good. In the second half of the play the story becomes more anxious and gloomy, and also dreamy and mystical. While the first half was about familiar intertangled events, in the second half people seem to be drifting away from each other, into separate worlds.
John Simm, of course, I thought was beautiful. He had more opportunity to move about in the first half of the play, which is always lovely to see. In the second half he plays a working class man suspected of murder, sitting at a police table telling his story to nobody, and a lonely policeman interviewing the dead woman's husband. He is mostly static and inward turning in these scenes.
Selfishly, I liked his more comedic, lively, dancing action in the first half - though I think the play itself got better and deeper as it progressed.