WHAT DOES IT mean to be a hero? Ask British novelist Lee Child and he will present the classic loner, a man with no ties who fixes the world and goes back to wherever he came from once the baddies are vanquished. Another English professional, stockbroker, Sir Nicholas Winton fits this bill in a sedate and enormous way, brought to deeply moving relevance in One Life, directed by James Hawes and performed by the beautiful Anthony Hopkins (Winton in his latter years) and the wonderfully cast Johnny Flynn, who plays Winton as a young man. It’s a film which takes the notion of ordinary decency in the face of catastrophe to its rightful heights.

In short, it’s truly a perfect work. The story is well known. Hampstead-born Winton pulled all the bureaucratic strings necessary to enable 669 Czech children to be transported by train to England, in the moments before Hitler overpowered Czechoslovakia, during the Second World War. These children would be fostered by different families with the wherewithal to do so, in their hearts and their pockets. Why? Because he saw that someone needed to do something. He saved their lives. And then went on with his.

That moment of Winton confronting an audience, some fifty years later, full of the now elderly children he had had a hand in saving from certain death in the European Holocaust, was broadcast in 2020 on the internet in a film clip from the popular 1980s BBC TV show That’s Life. It’s there in Hawes’s film but the build up to that magnificent denouement is the muscle that makes this film a must-see.

Veering cleanly away from schlock or the kind of easy fictional romances that a tale of this nature would spawn for box office attraction in lesser directorial hands, the story doesn’t show you anything of the horrors of the Holocaust or the nature of the bureaucratic channels Winton had to negotiate. You get a sense of the insuperable weight of his task. You understand that he wins. And the sociopolitical backdrop of the work comprises unbelievably powerful tesserae of a mosaic of human destiny. To call them cameos would be hyperbolic. These are glimpses at horror and devastation, at bewilderment and heartbreak, at the dreadful moment of letting go, knowing that parents and children would never be able to hold one another in this world, again; but it’s all in tiny homoeopathic moments. Moments that are about the toothless cheeky grin of a six-year-old urchin; or about a 12-year-old taking care of a baby orphaned by strangers; or about a little girl’s love of skiing and swimming; or a family having to keep their youngest son because the strangers overseas could not foster three boys, but only two. Cohesively, this texture is the fabric of life and in just these pinpricks of insight into the lives of children threatened by war, broken by displacement, a whole history is extrapolated with all its implied complexity.

Helena Bonham Carter is the young Winton’s fierce Jewish mom, Babette, who came out of Germany in the previous war, and who will not take no for an answer, and Romola Garai plays economist and humanitarian Doreen Warriner. It’s a tough role about being a woman in the 1930s without any of the frills attached. She’s terrified and furious and passionate about helping refugees and keeping her staff safe. Garai’s performance is electrifying and gives you a sense of what it means to roll up one’s proverbial sleeves in the face of insurmountable catastrophe and do what must be done, come what may.

And that is what brings you to the conceptual crux of this piece of filmography. A Hebrew idiom from Ethics of the Fathers that offers a bit of a catch-22: You are not required to finish your work, yet neither are you permitted to desist from it. Underlined by the Talmudic injunction that one who saves one life is considered by the sages to have saved the whole world, the work sits in a perfect reflection of the value of decency, without being heavy handed on the political or historical fronts. It’s about having the ability to reach out a hand to a stranger. And expect nothing in return.

You go away with an understanding of humanity rather than one of war and lots of real tears shed. Bring a box of tissues.

• One Life is directed by James Hawes and features a cast headed by Henrihs Ahmadejevs, Martin Bednár, Alex Bílík, Nick Blakeley, Helena Bonham Carter, Sean Brodeur, Daniel Brown, Darren Clarke, Anna Darvas, Anna Datiashvili, Daniel Charles Doherty, Joel Edwards, Anna Eliseeva, Samuel Finzi, Johnny Flynn, Antonie Formanová, Romola Garai, Henrietta Garden, Tom Glenister, Michael Gould, Valerie Hazan, Ziggy Heath, Anthony Hopkins, Ffion Jolly, Marthe Keller, Angus Kennedy, Alara-Star Khan, Kiana Klysch, Emily Laing, Ágnes V. Móricz, Juliana Moska, Lena Olin, Jonathan Pryce, Stuart Ramsay, Adrian Rawlins, Rút Schmidtová, Alex Sharp, Liam Smith, Samantha Spiro, Tim Steed, Matilda Thorpe, Bitu Thomas, Michael van Koetsveld, Joe Weintraub, Alan D West, Julia Westcott-Hutton, Stuart Whelan and Marie-Claire Wood. Written by Lucinda Coxon and Nick Drake, based on the life story of Sir Nicholas Winton, it is produced by Iain Canning, Guy Heeley, Joanna Laurie and Emile Sherman and features creative input by Volker Bertelmann (music), Zac Nicholson (cinematography), Lucia Zucchetti (editing), Lucy Amos, Nina Gold and Arwa Salmanova (casting), Christina Moore (production design) and Joanna Eatwell (costumes). It launched at Cinema Nouveau movie theatres around South Africa on 5 January 2024.