Agnieszka Holland’s Mr Jones is a bold and heartfelt movie with a real Lean-ian sweep. First-time screenwriter Andrea Chalupa has been inspired by her grandfather from eastern Ukraine to script this forthright, valuable drama about Stalin’s genocidal famine there, and the courageous Welsh journalist Gareth Jones who first brought it to the world’s attention in the 1930s. This was despite real personal danger in journeying there covertly – and the subsequent disparagement of Stalin’s lickspittle New York Times correspondent in Moscow, Walter Duranty, a man whom posterity has revealed to be a singularly useless idiot.

James Norton brings his A-game to this film, giving a muscular, sympathetic performance as Jones, the idealist intellectual and man of action from Barry in Wales, who has a liking for reciting the medieval Welsh poem The Battle of the Trees and never removes his sweetly owlish spectacles. Peter Sarsgaard is the creepy Duranty and Joseph Mawle has a recurring cameo as George Orwell who was said to have been inspired by Jones’s work and might even have named “Mr Jones”, the proprietor of Animal Farm, after him. Jones and Orwell don’t appear to have met in person, but the film imagines a lunch encounter, based on the fact that they shared a London literary agent: Leonard Moore. The movie has also created what appear to be fictional composites: chiefly a colleague of Duranty’s called Ada Brooks, played by Vanessa Kirby (Princess Margaret from the Netflix series The Crown).

Holland’s film begins slowly, even unassumingly as young Jones – having already made a splash by interviewing Hitler – uses his London government contacts with David Lloyd George (Kenneth Cranham) to get official permissions to travel to the Soviet Union, on a mission to interview Stalin and discover the truth about the USSR’s colossal economic expansion and its apparently triumphant five-year plan. At first, Jones is restricted to Moscow, condemned to hang around the louche and cynical journo-expat scene presided over there by Duranty. But then he escapes to make a dangerous and deeply unofficial trip to Ukraine, which is where his nightmare begins.

At first, the movie is weirdly like The Third Man, with Jones as the Holly Martins figure, the writer in a strange town, having been promised something interesting by someone who is disturbingly no longer around. But by the end of the film it is more like Heart of Darkness. He befriends Ada (Kirby) who wearily tolerates the secret service man following her around as her “big brother”, and Jones is unnerved by a man at one of Duranty’s creepy parties saying that the ennui-stricken hedonistic atmosphere is like Poe’s The Masque of the Red Death.

When Jones arrives in the desolate, snowy wastes of eastern Ukraine, he finds out the truth about what Stalin is doing – and perhaps the fact that this is still not well known adds to the horror. There is an excellent and disturbing scene in which Jones is confronted by five tiny children in snowy woodland who sing an eerie song to him about Stalin, and about how cold and hungry and yet loyal they are. It has a sinister, hypnotic effect. Jones is to become tormented by hunger, even gnawing at tree bark. Finally a thin-faced family share their supper with him, which turns out to be the worst horror of all.

The movie is partly about Jones’s personal nightmare and his anguish when he was at first disbelieved. But it is also about his final vindication, which perhaps doesn’t have the same power although it’s a necessary part of the story.

Holland’s movie really lets rip in the final act, the ordeal in the wasteland of Ukraine. She has a real story to tell – a story that isn’t told enough – and a single, compelling and likable character with which to tell it. It’s a picture with sinew and strength.