Heidi Thomas’s new play about the last months of Tsar Nicholas II and his family is unusual in that we already know how it’s going to end. In that sense, at least, it resembles Greek tragedy. The only question is, how will she shed new light on this familiar story, best known, perhaps, through Nicholas and Alexandra (great book and film)?

The piece opens in 1918, with the family incarcerated in the House of Special Purpose, in Ekaterinburg, and we are immediately in the intimate presence of one family’s strained but heart-warming life. Thomas gives us only shreds of the political and historical background, which is wise, as it is fantastically complex and hard to follow by this stage, and often unknowable. We’re still not even sure which nationality the soldiers were who murdered the Romanovs: possibly Latvian, possibly Hungarian. The Bolsheviks feared Russian soldiers would refuse to follow orders, especially regarding the girls.

The House of Special Purpose works primarily as a portrait of a relatively normal, happy, quarrelsome family that also happens to be hated by millions, and revered by millions more still as the family of God’s vice-regent on earth. Instead of misguided attempts to dramatise the bigger picture of Whites and Reds, Bolsheviks and Men­sheviks, provisional governments and constituent assemblies, which might test the powers of the most assured dramatist,

Thomas gives us the tsarina showing a tender solicitude toward the tsar of all the Russias and his haemorrhoids. (Treatment is effected with some ice cubes wrapped in a cloth and shoved up his nightie, if you’re curious.) The disjunction between the autocratic figurehead who ruled by divine right only a year before and the whimpering man under his sheets in this miserable prison house in Siberia is comical and poignant.

Rich character studies are realised by some wonderfully natural and relaxed acting. Adrian Rawlins is entirely credible as Nicholas, the fond father of four lively daughters: ebullient, eager, kindly and not very bright, reduced at one point to negotiating with the guards over whether they might have a fresh samovar each morning. Clare Holman is, quite correctly, a rather unlike­able Alex­andra: haughty, snappish, obsessed with her son and frostily denouncing her daughter Anastasia’s “ghastly thick wrists”, like those of a peasant woman. Otherwise, it’s a very girlish household, with its four pretty daughters flitting about, laughing and dancing and singing like birds i’the cage. They talk about boyfriends, swap clothes and sneak nocturnal cigarettes, but Thomas, aided by the director, Howard Davies, never makes us feel that these are merely modern girls in costume. They are still very much Romanov princesses, hopelessly naive, beautifully spoken, blushing to be caught by the guards wearing only their petticoats. Special mention for the understudy Annabel Scholey as Olga, the Cassandra of the family, who takes on the role flawlessly.

As for the Tsarevich Alexei, the youngest at 13, Thomas’s portrait strongly suggests that, had he survived, he would have been a monster of a tsar. Pet­ulant, spoilt, malicious, self-pitying and manipulative, he is a little tyrant in the making. Anastasia, the most amusingly down-to-earth of the sisters, comments drily after yet another hissy fit, where he throws his toys out of the wheelchair: “See what happens when you give someone a 400-gun salute the day they’re born.”

There is a lack of tension in the second half, given the approaching atro­city. A scene between a young servant girl, Worker 28, and a Cheka interrogator is a pointless tangent that adds little. There are not one but three romances between the girls and their guards, only Olga being un­interested, with the suggestion that she has been raped. All this strains plausibility, although the scenes of hesitant flirtation and chaste kissing are rather touching.

Despite the gruesome ending, this is not a tragic play, and often markedly comic. Only once or twice does a character say that things can only get better, “We must stop expecting disaster”, or that “the worst has already happened”. Thomas is right not to overdo it. Instead of portentous dramatic irony, we have the minutiae of domestic life in a close-knit and rather lovable family, cruelly cut short by history. The conclusion seems less like an atrocity than a long-expected full stop. The slaughter takes place off stage — Greek tragedy again — the guards luring the family down to the cellar, saying they are being taken to a better place. For the first time, it struck me that this was exactly the lie Nazi concentration-camp guards told their prisoners before execution. All totalitarianisms grow to resemble one another.

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