To make a nuclear bomb, you assemble enriched uranium into a supercritical mass that starts an exponentially growing chain reaction. Tom Morton-Smith’s play assembles the team building the first nuclear bomb and shows the chain reaction that ensues amongst them. And just as a bomb needs a trigger, the “Manhattan Project” needed J Robert Oppenheimer.

The play questions whether the physicists were mad scientists who should have known better than to participate in such a project and how far they felt justified at the time, even if subsequently doubting the genie they had unleashed that cannot be put back in the bottle.

Morton-Smith sees the events through the lens of Oppenheimer, intertwining his intellectual struggle with the physics and his emotional struggle with the need to abandon his early and fervent embrace of communism, which Oppenheimer saw as the only remedy to Fascism, in order to appease the US authorities. He had after all been schooled at New York’s Ethical Culture School, where many of his fellow pupils were also secular Jews and where he discovered the ethical teachings of Judaism. And later he was engaged by other ethical texts and scriptures including the Bhagavad Gita (a 700-verse Hindu scripture in Sanskrit), which stayed with him all his life and Morton-Smith has him quote it at the end of the play.

J Robert Oppenheimer (the J stands for Julius) may have been born in Manhattan, but as the son of German-Jewish immigrants, he was acutely aware of the fate overtaking Europe’s Jews, especially as the US scientific community welcomed an influx of eminent Jewish physicists seeking refuge from the Nazis. The list of characters in the play is in part a roll call of these brilliant fugitives, most of whom would go on to win Nobel Prizes. In addition, the young prodigy had studied under (Jewish-born) Max Born in Göttingen in Germany in the 1920s, gaining his PhD at age 22. So he was much exercised by the rise of fascism in Europe.

After a brief lecture from Oppenheimer, with the audience cast as students, Morton-Smith starts the action with an upbeat party scene on the Berkeley Campus at a Communist fundraiser for International Brigade members off to fight fascism in Spain. It’s the sort of party at which anyone who’s anyone in the intellectual and academic community must be seen. Morton-Smith’s brilliance is to cut between the party and the students and academics in full creative flight as they learn and teach in the lab – using the stage floor as a chalkboard on which they feverishly scribble theorems and theories. Even the chronically unscientific members of the audience (among whose number I count myself) immediately get the feel of how engrossing and exhilarating the pursuit of scientific knowledge and discovery must be for members of the scientific community. This works especially well as a counterpoint to the party segments – all choreographed with huge panache by Scott Ambler.

Everyone in this community is aware of the work of German scientist Werner Heisenberg and his Danish-Jewish mentor Niels Bohr in Europe (as brilliantly imagined in Michael Frayn’s play Copenhagen). Is Bohr making a stand against letting Hitler get anywhere near the bomb? Does Heisenberg dread the ‘fall-out’ from The USA getting there first? Well, clearly in the USA they see it as a necessity to get there first and scientists are under intense pressure to do so. But Morton-Smith imagines, with the feel of chilling authenticity, not only the pressure but also the febrile excitement of these extraordinarily focused (often one-track) minds as they realise they are nearing a breakthrough, albeit one that will prove deadly to millions.  The detachment with which the boffins discuss the bombs they call Little Boy and Fat Man and what they are capable of, with a matter-of-factness about the numbers of Japanese likely to be sacrificed, is frighteningly convincing.

John Heffernan brilliantly inhabits the persona of Oppenheimer, mesmerisingly charismatic from the moment he engages with the audience at curtain up. He embodies the struggles and contradictions in the man – a womaniser with “a core of cold iron” – with a wife and mistress; scared that he has the scientific ability “to murder every last soul on the planet, yet at the same time a leader who expects to be followed. And indeed he is the magnet that attracts a huge number of scientists to join him at Los Alamos to work on the Manhattan Project.

Morton-Smith creates wonderfully authentic communities and he plays up the friction between the unruly scientists and the military with their, ahem, 'military' precision at Los Alamos to terrific and rather comedic effect.

Morton-Smith’s portraits of Oppenheimer’s women are especially complex. There’s Catherine Steadman’s mercurial manic depressive Jean Tatlock, the mistress who checks in and out of his life, in her element rallying the intellectuals for the communist cause. And Thomasin Rand’s wonderfully vivid Kitty, another bright and frustrated female intellect, who leaves her previous husband to marry Oppenheimer, only to find herself reluctantly kicking her heels though not her alcohol habit through pregnancies before and during her stay at Los Alamos.

Angus Jackson directs with panache a large cast in a production that sweeps effortlessly from those cocktail parties in Berkeley to the then empty plain of Los Alamos, thanks to designer Robert Innes Hopkins, whose costumes – especially for the women – are both authentic and stunning, and the action is heightened by Grant Oldman’s exhilarating score played live by a superb six-piece band directed by Jonathan Williams, and that organic choreography by Scott Ambler.

By Judi Herman

Oppenheimer runs until Saturday 23 May. 7.30pm, 2pm (Wed/Sun only). £25-£49.50. Vaudeville Theatre, 404 Strand, WC2R 0NH. www.vaudeville-theatre.co.uk