B, a new play by Chilean playwright Guillermo Calderon, isn’t necessarily what you expect from the Royal Court – wooden acting, stock characters, awkward, unnatural dialogue – it feels a bit amateur a lot of the time. Except that’s the point; it’s done like this very deliberately.

Alejandra (Danusia Samal) and Marcela (Aimee-Ffion Edwards) are total amateurs. Left-wingers? Anarchists? They don’t really seem to know themselves. They just set bombs to kick-start the revolution.

Jose Miguel (Paul Kaye), on the other hand, is an expert. He’s been agitating for change for decades, he’s spent time in East Germany, Sri Lanka, Colombia, you name it, and now he’s making bombs for others to set because he wants lasting change. And he’s never been caught, whereas Alejandra and Marcela almost were. And now Marcela’s obvious lie to Carmen (Sarah Niles), the next-door neighbour, about how her boyfriend was blown-up terrorists, threatens Alejandra and Marcela’s meeting with Jose Miguel, just as he’s about to deliver the bomb to them so they can go plant it in a bank.

Like Chris Morris’ Four Lions, B makes the relatively unexplored point that people who set off bombs aren’t necessarily idealogues with clear worldviews and a definite purpose. And they’re mostly pretty incompetent.

While Jose Miguel knows what he does, why, and how best to do it, and keeps his face covered and his hands gloved and has lies prepared for when he runs into nosey neighbours, Alejandra and Marcela are just angry kids out for fun and new experiences. And what they don’t realise is that they’ve been incredibly lucky to have been neither caught or blown-up. They think Jose Miguel’s bourgeois. He thinks they’re young and stupid. They’re both right.

And what of Carmen, who keeps popping in and initiating some painfully bizarre exchanges with Alejandra and Marcela. She clearly thinks they’re suspicious, but she also seems a bit mad. Mad enough – or canny enough – to go to the police?

This is an unsettled, occasionally funny play and director Sam Pritchard, composer Teho Teardo and designer Chloe Lamford create a tense and disturbing experience for the audience. Teardo’s music, which creeps up on you as the characters deliver major speeches, is particularly effective.

But when the denouement of B finally arrives, and it can only really go one way, it feels like a letdown. Do we know much more about the motivations of bombers? And has all this achieved anything? It seems not. Which is apt.