Ealing Studios are best known for their post-war comedies, which gently satirised British society. But one earlier Ealing production had a much more direct political edge and a sci-fi element to boot – their adaptation of the J. B. Priestley play They Came to a City.

The city in question lies in a mysterious dream-like realm, which nine disparate Britons are suddenly transported to. The first half of the film sees them exploring the strange architecture of the city’s gatehouse, waiting for the door into the city below to open. The second half sees a conflict between these characters spark as they return from the city, having found it to be a socialist civilisation quite distinct from the class-stratified Britain they’ve come from.

So we never actually get to see this city, just hear about it through dialogue, with the entirety of the story (excluding an odd and unnecessary framing device starring Priestley as himself) taking place in this strange futurist gatehouse. While this is an impressively striking set, the static nature of the drama does rely heavily – perhaps too heavily – on the script’s theatrical origins.

Which means that the success of the film relies on its characters and dialogue. Thankfully, from a skilled playwright like Priestley, many thought-provoking themes are brought to the forefront of these interactions. It’s a story highly concerned with class; the City banker and fusty knight of the realm see the city as an uncivilised dystopia, while the working class mechanic and cleaner see it as quite the opposite, a utopia. The story also touches on issues of misogyny, with Googie Withers’ waitress Alice fed up with the way men treat her in the world she comes from.

While these issues are powerful and indeed still relevant, however, the lack of subtlety with which they come to a head in the final minutes may grate on some viewers; John Clements certainly pulls no punches with his rousing speech calling for us to make our own world a better place, but in moments like these, the film gets so preachy about its politics that it almost forgets it has a story to tell.

This new dual Blu-ray and DVD release from the BFI looks great in high definition and comes with an impressive bunch of extras. Highlights include a lecture from producer Michael Balcon about his career; a short GPO documentary about communications technology, narrated by Priestley; a 20-minute propaganda film written by Dylan Thomas; and an animated short on the new National Health Service – all clearly of their time but nonetheless fascinating to those interested in British history.

THEY CAME TO A CITY (1944) / CERT: U / DIRECTOR: BASIL DEARDEN / SCREENPLAY: J. B. PRIESTLEY, BASIL DEARDEN, SIDNEY COLE / STARRING: JOHN CLEMENTS, GOOGIE WITHERS, RAYMOND HUNTLEY / RELEASE DATE: APRIL 23RD