Sir Michael Redgrave (Captain Karel Hasek) and Rachel Kempson (Celia Mitchell) were married from 1935 until his death in 1985.
The Marlag und Milag Nord prisoner of war camp, where this movie was set and much of it was filmed, was located in the north of Germany, about thirty kilometers (18.6 miles) from Bremen. After the German surrender, it was used to house German prisoners of war and then later female refugees. In the 1960s, it was a base for a Luftwaffe division of the German Army, but today, it is a business park.
Co-writer Guy Morgan was in fact a prisoner of war in the German prison camp of Marlag und Milag Nord where parts of the film were shot.
The character played by Sir Michael Redgrave (Captain Karel Hasek) was inspired by a real person, a Czechoslovakian military pilot named Josef Bryks. Before his involvement in the Royal Air Force he led a very brave and adventurous life. He survived the whole of World War II, but couldn't know what awaited him upon his return to his homeland. After the Communist putsch in 1948, he was dishonorably discharged from the Czechoslovakian Army. After several false court proceedings, he was eventually sentenced to thirty years in prison and work in the uranium mines. There he experienced worse conditions than those in Nazi prison camps. Until his death, he never buckled to the Communist injustice. He died in 1957 as a result of torture and inhuman treatment.
The 2016 digital restoration was funded by StudioCanal in collaboration with the British Film Institute's "Unlocking Film Heritage" digitalization program, which is part funded by the UK's National Lottery.