“The girls are grown, they’ll be gone before we know it.” So says Clare Holman’s captive Tsarina as she cuts the hair of Adrian Rawlins’s captive Tsar in Ekaterinburg, speaking with greater accuracy than she realises. And that’s one problem with the modestly entertaining picture of the last months of the Romanov family to which Heidi Thomas has given the same ominous, sinister title that the Bolsheviks gave their prison. They’ll all soon be gone: Olga, Maria, Anastasia, Tatiana, their parents and their haemophiliac brother, Alexei.

Well, most of us know how Hamlet or Lear will end before we sit down. And a dramatist who sacrifices conventional tension for a sense of foreboding need not be another Shakespeare. But to keep an audience gripped, he or she must be especially imaginative. And here’s another problem. Thomas takes liberties with the truth as we know it, or at least as it’s recorded in Robert Massie’s fine book Nicholas and Alexandra, but doesn’t compensate with invention that surprises and satisfies enough.

In fact, the Romanovs were vindictively treated by their first commandant, Alexander Avdeyev, a commissar who taught his men to insult and mistreat “Nicholas the blood-drinker” and his family. Though someone prints an obscene double-entendre about Rasputin on Olga’s knickers, that’s much underplayed here.

Indeed, Thomas’s purpose seems to be to show several of the guards thawing towards their always polite and considerate prisoners, one even coming close to aiding an escape, and their prisoners mostly accepting their lot with stoicism and, at times, resilience. Citizen Romanov saws logs and is rewarded by Avdeyev with a cig. Citizen Maria doesn’t just take joy in learning to iron: she falls half in love with the launderer.

As played by Lydia Wilson and Kieran Bew, this is touching stuff. So is the bond between Rawlins’s affable, upbeat Nicholas and Holman as a sweeter, less haughty Alexandra than the original. And though Jonathan Bailey’s Alexei remains a sullen, self-pitying figure, the four girls are as attractive, lively, wayward and mischievous as any in an Angela Brazil dorm. They spend much of Howard Davies’s production frolicking, teasing and generally giving the impression that, had they lived, they would have added some much-needed fun to Europe’s royal houses. You’re sorry when the shots ring out — but, since you knew they were coming, what can you do but shrug?

Box office: 01243 781312, in rep to Aug 22

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