Theatre Royal, Haymarket | ★★★★✩

Albert Einstein, Hans Bethe, Lise Meitner, John Von Neumann and Edward Teller – some of the Jews who, the German atomic scientists in Katherine Moar’s debut play,  lament might have enabled them to beat the Americans to the bomb.

But it is an academic point. If Jewish theoretical and practical physicists had been allowed to work with their German colleagues then it would not have been the kind of regime that started the Second World War.

There is time for such ruminations in this absorbing thriller. It started life at Jermyn Street Theatre and has now deservedly become a rare example of a West End play driven not by star power but by intelligent writing and excellent acting. That said, the cast does feature highly respectable names such as David Yelland as Von Laue and Alan Cox as Werner Heisenberg. They are two of six German scientists who are comfortably imprisoned in a Cambridgeshire mansion.

To while away the vacant hours, days, weeks and months they attempt a spot of am-dram, play chess and the piano. Mostly, though they talk while trying to self-censor especially when it comes to their work to make Hitler’s Germany the world’s first atomic power – unseen British guards are listening to them. But time breaks their discipline especially when a radio announces that the Americans have used the bomb against Japan.

Julius D'Silva Photo: Alex Brenner

Directed by Stephen Unwin the play would make a great companion piece to Michael Frayn’s modern classic Copenhagen which imagines the meeting between Heisenberg and his Danish mentor Niels Bohr and wonders whether the meeting prevented or was intended to enable Nazi Germany’s quest to be first to build the bomb.

Farm Hall is also based on real-life encounters. The German scientists were right to wonder if they might be being listened to. But even they hadn’t realised almost every inch of the mansion was bugged. Using the transcripts declassified in 1992 Moar has created a chillingly convincing play that conveys just how close the world came to a Nazi atom bomb.