Sir Nicholas Winton, who saved hundreds of children from the Nazis, was so modest that he rejected an initial proposal to make a film about him, according to the producer of One Life, the soon-to-be released biographical drama about the British humanitarian.

Iain Canning told the Observer that, about five years before Winton’s death in 2015 aged 106, he and fellow producer Emile Sherman visited him at his Maidenhead home during a break from shooting their film, The King’s Speech.

Over tea, they broached the subject of making a film about the man who helped save 669 children from German-occupied Czechoslovakia, just before the beginning of the second world war, but Winton politely turned them down.

“I still to this day call it the worst meeting I have ever had,” said Canning. “He was 99 or 100 at the time. We said, ‘We think what you did was absolutely incredible and we would love to make a film about that particular moment in your life.’ He said, ‘Oh, no one else needs to know what I did. No one else. Anyone who needs to know about this, already knows about it.’ ”

Canning added: “He was a man with such kind eyes. We were humbled by him.”

The King’s Speech went on to be nominated for 12 Oscars, winning four, including best motion picture, but the producers never forgot Winton. After his death, they worked with his daughter, Barbara, who gave them access to his archives, but she died in 2022, midway through principal photography.

Canning said that Winton had reluctantly allowed his daughter to write his biography and that he was later “open to his life being explored in other ways”. But it was on condition that he was not portrayed as “super human” and “that what he did wasn’t within the capacity of other people”.

Barbara had suggested that they approach Sir Anthony Hopkins for the role. Canning said: “He very quickly came back and said, ‘Would it be possible to get Barbara’s email because I want to ask permission to play her father?’ ”

The Oscar-winning star was inspired to play a man who, alongside others, saved the lives of children who were otherwise destined for the gas chambers and furnaces of Auschwitz, Treblinka and Belsen.

One Life, released on 1 January, tells the story of “Nicky” Winton who, as a young London broker, visited Prague in December 1938 and found families who had fled the rise of the Nazis in Germany and Austria. They were living in desperate conditions with little or no shelter or food, and under threat of Nazi invasion. He immediately responded to their plight and, in a race against time, tried to save as many children as he could before the borders closed.

He was to be haunted by the fate of 251 children he was unable to bring to safety. They had boarded a train at Prague station but that was the very day war was declared and the borders were closed. The Nazis pulled them off the train and most were murdered.

The film re-enacts the 1988 live episode of the BBC television show That’s Life!, which introduced Winton to some of the surviving children – who were by then adults. It enabled him to come to terms with the guilt and grief he had carried.

The film recreates the moment that presenter Esther Rantzen said to the audience “anybody who owes their life to Nicky Winton, please stand up”. The entire audience rose.

It was only when they filmed the scene that Hopkins discovered that the extras making up the show’s audience were the actual children of those Winton had saved: “It was very moving.”

Those rescued by Winton include Lisa Midwinter, 88, who was aged three when she travelled on the Kindertransport, but some memories have never left her: “I remember everybody crying.”

Unusually, both her parents managed to escape to join her. Her father had been a paediatrician and, with his wife, set up an orphanage for Czech children in Stoke-on-Trent.

She never found out how they escaped: “It was too painful for them to talk about.” Her grandparents and aunt perished in the concentration camps. She spoke to the Observer with her son, Nick Wyse, who said that they only discovered details of her Kindertransport escape through the That’s Life! programme. It happened to feature photographs from Winton’s scrapbook – and there was one of her aged three.

She later got to know Winton and remembers his “lovely sense of humour” and extreme modesty.

Her son said: “It’s hard to be truly dispassionate about the film, given our emotional connection with it. But trying to stand back, Hopkins is just incredible. He brings huge gravitas and humanity. It’s an uplifting film – a beacon of hope, saying that in the midst of the greatest of horrors, there can be examples of doing good.”

Mike Levy, a Kindertransport historian and author of Get the Children Out!, met Winton several times: “He was incredibly modest and slightly embarrassed by the fame that had come his way following the That’s Life! programme.

“He felt he’d done his bit and moved on in some ways. He wasn’t a person who wanted any fuss.”