Imagine this? That’s the title of a show that involves Jewish actors performing an inspiring play in the Warsaw Ghetto; but it also comes across as a mix of command and plea. And, sorry, no can do. Last night Glenn Berenbeim’s book began by making me feel my imagination might take fire, only to douse it with the sort of formulaic nonsense it has resisted a zillion times before.

When the Nazis are brutalising Peter Polycarpou’s Daniel and his troupe beneath the broken glass, grim brickwork and iron stairways of Eugene Lee’s set, there’s a promising sense of reality in the murky air. And the idea of these actors presenting a play about Masada, the redoubt where zealots committed mass suicide after the destruction of Jerusalem, is refreshingly bold.

But I should have been warned by lines such as (to Daniel): “In a ghetto full of misery only you can come down with a bad case of optimism.”

That clunkiness never goes and it’s accompanied by a major loss of nerve on everyone’s part.

Soon we get none-too-tasteful comic relief in the form of a Christian slave called Pompey from Pompeii: just before being cheerfully crucified he sings a patter song about Jupiter being no Zeus and Aphrodite being flighty. And, worse, the love that inevitably burgeons between Leila Benn Harris as Daniel’s daughter and Simon Gleeson as the ghetto fighter he’s hiding is replicated in the play-within-the-play.

Gleeson becomes the very earnest Roman general ordered by Caesar (“go back to Judaea or I will crush you like a grape”) to destroy Masada. But his heart already belongs to Harris’s pretty Tamar, who has given him a rose and so convinced him that “what was once a cursed race has taken on a human face”.

I won’t tell you how this turns out, only that it comes with a lot of stuff about dark eyes burning through me and how deep eyes somehow knew me. The lyricist, David Goldsmith, may have the chutzpah to rhyme nature with nomenclature, but he can be pretty slushy too.

Similarly, Shuki Levy’s score can handle the sad or upbeat, notably in a soaring title song that claims that only imagination can free the oppressed. But it never has the minor-key harshness the situation demands.

And what of the number involving undulating belly dancers and prancing Roman soldiers?

That’s something nobody should have imagined.

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