I had trouble shifting my +1 for the musical Imagine This, which opened last week at the New London Theatre. No-one was interested (one German friend would have come, but funnily enough I hadn’t thought to ask him), and while nobody actually said, “Sounds like a gas”, there were plenty of unprintable responses, averaging out at: “Holocaust – the musical? Um, no thanks . . . ”

But it’s not that. Nor is it really a love story as advertised (though it’s not hard to see why the producers opted for that evasive billing). What it is is a purposeful step away from an understanding of Jewishness based solely on photos of starving prisoners, and a pretty good stab at de-victimising Europe’s Jews through a drama of freedom and hope.

It is 1942, and a Warsaw ghetto theatre group find themselves sheltering a resistance fighter, Adam (Simon Gleeson), an act of humanity which nearly costs them everything when the SS burst in.

Their director, Daniel (Peter Polycarpou) is left ad libing an introduction to the cast of his historical epic, Masada – “You Nazis will love it. It’s got singing and dancing, and all the Jews die in the end!”

Apart from the thematic parallels (look ‘em up), this musical-within-a-musical catalyses a debate – in the face of the audience – as to whether there should be singing and dancing in (or about) the ghetto. Daniel believes every performance constitutes an act of resistance in itself. Others, including his daughter, Rebecca (Leila Benn Harris, pictured), think it only perpetuates false hope.

Cannily, it also offers a get-out clause for the worst excesses/inevitabilities of the genre, thereby dodging accusations of questionable taste in Shuki Levy’s obligatory cheery numbers and romantic duets. That said, the Salomé arse-wiggling number (with Boyzone dancing legionaries) sails pretty close to the wind; Pompey the camp Christian frankly deserves to be nailed up; and David Goldsmith’s rhymes too frequently exhibit all the lyricism of a tearing ligament.

Warsaw and Masada are not subjects famously imbued with humorous potential – excepting that the Romans spent months building a ramp up the Judaean mountain, only to discover the rebels had all killed themselves – but Glenn Berenbeim’s script is encouragingly witty, and contains several of the best Jewish jokes in the repertoire. Naturally, these were greeted with horrible silence. People just don’t believe you can laugh at these things (though they’ve no problem stuffing their faces with Revels while they pass judgement).

Imagine This is good, but, I fear, ill-fated. Judging from the vacant seats on night two, every performance will indeed constitute something of an act of resistance.

Imagine This is at the New London Theatre. Box office tel 0844 412 4654 (www.ImagineThisTheMusical.com).