Let’s get one thing clear from the start: this play is not about Boris Johnson. It is not an allegory, it is not a pastiche, and it is not a political satire; it is not about Brexit. It is literally about Boris III, the erstwhile king of Bulgaria, who did a deal with the Devil in the shape of the Nazis but who maybe - just maybe - made the right call. It’s a dark and difficult story, shamefully unfamiliar to most of us… yet this show manages to tell it it with with humour, lightness, and song.

Boris is a divisive figure, as the play does make clear; but whatever you think of his legacy, you can’t deny he was dealt a difficult hand. The first few minutes comically summarise the network of feuds enmeshing inter-war Bulgaria, and by aligning with Nazi Germany Boris arguably chose what seemed to be the lesser of two evils. But then the deportations started, and it’s here that the story grows cloudy. By obstructing and delaying Nazi demands, Boris saved thousands of Jews… yet at other times he did nothing, and acquiesced in the murder of thousands more.

Joseph Cullen and Sasha Wilson’s script never forgets the gravity of its subject matter, but tackles it with verve and bittersweet comic flair. Boris himself, played by Cullen, is a kooky, other-worldly, but surprisingly wily figure; an embodiment not so much of Boris the man, but of the strange institution of monarchy. He’s literally the centre of attention - the audience sit on all four sides around him - as other characters dip in and out, in a colourful flurry of roles and scenes. It’s done with a broad brush, and cheerful reliance on familiar tropes: the functionaries surrounding Boris carry themselves like British aristocrats, while the antisemite Alexander Belev is as a charmless, jumped-up barrow-boy.

The five-member cast is uniformly strong, though David Leopold deserves particular credit for his portrayal of Belev: when he switches to that role, the transformation in his manner is so complete I was genuinely confused for a while about whether it was the same actor on stage. And the whole cast play instruments too. Music is a big part of this show; some of the tunes are familiar, others less so, some are upbeat and some are mournful. All are welcome, and all of them set the perfect pace and tone.

We’re told at the start that everything we’ll witness is true, and at times they even give citations for some of the more improbable claims. But as the programme notes apologetically point out, the full story is far too complex for a one-hour show; now I’ve read some articles online, I know it only scratches the surface of the controversy surrounding Bulgaria’s role in the Holocaust. Still, the script - while undeniably sympathetic to Boris - at least poses the questions, and actively prompted me to find out more. Within the constraints of an hour-long slot, I think it achieves all the balance it can.

This is an upbeat and enjoyable show, built around horrific events; and it squares that circle because it uses levity wisely. By gently satirising the circus of monarchy, it throws even sharper focus on the consequences of the choices Boris made. It does a good job, too, of filling in the back-story, untangling the twisted threads of international politics in a way that’s both accessible and fun. And by inviting you to empathise with the troubled Boris, it poses an even more troubling question: if you were in his place, what would you have done?