One Life is the story of Nicholas Winton (Anthony Hopkins), the British stockbroker who arranged the Kindertransport that saved hundreds of children from almost certain death in the Holocaust and be warned: you will need one tissue, if not two – maybe 12. Which isn’t to say it’s a great film. It’s fine, in its workmanlike way. But the story is so inherently powerful and moving and there is so much goodness and decency at work it will set you off. Take a whole box of tissues if you want to play it safe and would rather not deploy your sleeve.

Hopkins’s performance is quiet, patient, masterly and as understated as the man himself

Directed by James Hawes with a screenplay by Lucinda Coxon and Nick Drake, the film opens in 1988 with Winton’s appearance on That’s Life. If you have never seen that clip, which has been viewed more than 40 million times online, look it up with those tissues to hand. No one had ever heard of him before, as he was the opposite of a virtue-signaller (perhaps a virtue-burier?).

By this time Winton is 78, retired, living with his wife, Grete (Lena Olin) in Maidenhead. (Did he really live in such a modernist gem? He had taste on top of everything else.) He has promised Grete that he will clear out his office by Christmas, which sets him sifting through old papers and the scrapbook he keeps in a battered old briefcase in a bottom drawer. His mind travels back, as we do, to the brink of the second world war in 1938, after the Nazi annexation of the Sudetenland.

Winton, now played by Johnny Flynn, visits a friend in Prague who is helping refugees. Living in makeshift tents they are starving, freezing, dying. He vows to help and on his return to London he and his fiercely forceful mother, Bibi (Helena Bonham Carter), harangue and cajole officials into issuing visas for the children. Shamefully, the British didn’t make it easy. Each child had to have a foster family in place and be sponsored to the tune of £50 (£3,500 in today’s money). It was thought they would be reunited with their parents at a later date. They never were. The scenes at Prague train station, where terrified children board trains and wave goodbye to the mothers and fathers they will never see again, are especially hard to bear. That’s six tissues, right there.

You’d really have to put the work in to make a bad film of this, but it never flies cinematically and often feels like a TV movie. It’s more of a join-the-dots endeavour than a story recounted with any stylistic or narrative flair and it offers few insights into Winton’s interior life. I had no idea both Winton’s parents were German Jews who had converted to Christianity on arrival in this country (to integrate, presumably), and that he had been baptised. This is all dealt with in a single sentence, but what this must have meant to him has continued to play on my mind.

Flynn and Bonham Carter have little to do and it’s the same with Romola Garai and Jonathan Pryce, who also pop up. But the fact that this is Hopkins’s film is a plus. His performance is quiet, patient, masterly and as understated as the man himself. If you’ve seen the That’s Life clip, you’ll understand the brilliance of Hopkins’s portrayal.

Winton saved 669 children – who were mostly Jewish but not exclusively – and would have almost certainly perished in the Holocaust. (To give you a sense of the horror: of the 15,000 mostly Jewish-Czech children who were sent to Theresienstadt camp, fewer than 150 survived.) Every life he saved is a mitzvah, and while the film is ordinary it can, to a large extent, get away with it because its subject is definitely not.