It has long been assumed that, in November 1940, Winston Churchill was aware that Coventry would be bombed on the night of the next full moon, but he ordered no extra precautions to be taken lest this suggest to Hitler that the British had cracked his Enigma code. So the city, almost undefended, was destroyed.

The dilemma that the Coventry-born Alan Pollock asks us to consider in his new play is whether we would sacrifice a city to win a war. And since we are unlikely to find ourselves in this situation, should Churchill, his Home Secretary Herbert Morrison and others in the know have chosen to do so? Morrison himself briefly appears, as does a retired gent we must assume to have been a member of Churchill’s inner circle, though neither of these allows us access to the morality of the decision. But another batch of people to know of the threat were the codebreakers at Bletchley Park, and it is one of these, Michael, a dashing young Oxford don before the war, who is burdened by Pollock with the guilt of knowing.

Hamish Glen stages his production in the Belgrade’s recently built second theatre, a three-level space too lofty to be called a studio, hence its bomber-like name B2. The traverse stage stretches from a freezing Bletchley Park at one end, where the personnel never remove their coats, to the interior of a Coventry terrace house at the other.

The space between represents various exteriors. It is first of all the station platform at Henley-in-Arden where, as in so many wartime romances, a man emerges from the steam of a passing train and falls in love with a woman. They are Michael (Daniel Brocklebank) and Katie (Joanna Christie), daughter of a union official and party man. Michael cannot reveal where he works. Neither can he, though knowing that her family is staying in Coventry on the fatal night, provide for their safety. The overwhelming guilt ultimately corrodes his sanity.

The progress of events towards the inevitable is enthralling and Brocklebank movingly traces the hero’s descent from a precarious bonhomie to unendurable shame. Less convincing is the dialogue of the Coventry characters in scenes that switch back and forth between locales and even timescales. Too often, these end on an unanswered question – the tiresome legacy of television soaps.

But the contrast between the seeming complacency of authority and the deaths, rapes and looting within the stricken city is telling, and little emphasis is placed on myths of the “Britain can take it” spirit.

The staging of the bombing – the whine, the flash, the deafening noise – is particularly vivid. Pollock’s question – should Churchill have abandoned Coventry like this? – may be unanswerable, but the reality of being caught in a rain of death has seldom been suggested so powerfully as here.

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