B

Royal Court Theatre

London SW1

IN B by Chilean actor, playwright and scriptwriter Guillermo Calderon, two generations of activists confront each other in a battle of ideologies over violence as a mean to achieve social change.

At its opening, two young anarchist teenagers stand facing each other in a sparsely decorated apartment. They have a plan. And they’re angry. Marcela (Aimee-Ffion Edwards) and Alejandra (Danusia Samal) want to plant a bomb outside a bank to scare people and “respond to the violence of capitalism with the violence of liberation” because “in this democratic dictatorship, all prisoners are political prisoners.”

Enter Jose Miguel (Paul Kaye), his face masked, who has a different and more bloodthirsty plan. He has brought a bomb hidden inside a lavishly decorated gift box. And he wants people to die.

In the light of the recent terrorist attacks in Britain but also the broader debate about extremism and political violence, Calderon's polemic is easy to grasp.

As the two girls and Jose Miguel embark on a fraught discussion about what kind of bomb to use — he forces Marcela to poo inside the box to make the nails surrounding the bomb lethally infectious — how to plant it correctly and what to say to the media after the explosion, it poses questions about why anyone would want want to carry out such a terrible act.

Older than the girls, Jose Miguel has been trained to fight in Libya, Belfast, Albania, Cuba and Managua. A veteran “monkey” in guerilla warfare, he's a sour nostalgist for a complex and difficult past. “We used to kill kings. We used to kill millionaires. And now all we do is make threats on the internet,” he says.

Bitter that he's spent years preparing himself “for the war that never was,” when he realises that both girls refuse to follow his plan, he berates them. He's decided to turn the pathetic war of “noise cows” (bombs) into a war of agitation and propaganda, into a “real” class war. “It’s the opposite of what you want to do. You want to fail, pathetically,” he adds bitterly, face uncovered.

The play's dramatic conclusion aims to show that revolution and violence mean completely different things to different generations.

As Marcela admits to the audience at the end: “I started a new war. This war. This fascinating war. The war outside. I can’t see it. I only get to hear the bombs. Far away. I would love to join the war. No. Maybe not. Actually, I would love to be on the sand.”

Runs until October 21, box office: royalcourttheatre.com