Playing on certain days before and after her own brilliant Love and Information, Caryl Churchill's 20-minute drama is not an add-on or a post-script; it's a tense, troubled game of two halves, in separate countries, with identical dialogue.

The characters change, but are played by the same cast on the same white set, with a national flag. A doorbell rings, the door opens, a man is shot, body dumped in a black bin liner. Same ring, drunken woman enters her own home.

Both households are "celebrating" a soldier going to war. A woman is locked inside. The trees are being destroyed. Our way of life is threatened. First a man, then a woman, worked for everything they have. A marriage is breaking up. An affair is underway. The vodka flows.

Dominic Cooke's production is a nationalist epic in shorthand, and deeply upsetting to watch. Each half ends with the group watching the death of a dictator (is he?) on television. The adoption of one character’s lines by another shifts the whole social pressure of the scene, and the tenor of attitudes to love, country and sacrifice.

In a lesser writer, and with lesser actors, this would come across as trivial or trite. With Churchill – and with this terrific, unwavering sextet of John Marquez, Sophie Stanton, Claire Foy, Stuart McQuarrie, Jennie Stoller and Daniel Kendrick – the play kicks in big time and detonates slowly inside your skull as you leave the building.