The Archers (Michael Powell Powell and Emeric Pressburger's production company) weren't given permission to film inside Canterbury Cathedral. In any case, the stained-glass windows had been taken out because of the air raids, the aisles were filled with sandbags and earth to fight fires and to provide a soft landing for any masonry or sculptures that fell there. So the interior of the Cathedral was rebuilt in Denham Studio. They recreated it so well that Cathedral guides have been heard telling people that the film was shot in there.
Gone with the Wind (1939) author Margaret Mitchell was on her way to see a showing of this film with her husband when she was hit by a speeding car. She was knocked out, and died five days later, having never recovered consciousness.
When Peter enters the cathedral he looks up towards the roof. That is the only shot that was taken inside the real cathedral. Despite not getting permission to film in there, the production sneaked that one shot with a hand-held camera.
The cathedral bells seen in the opening and closing shots were a miniature replica of Canterbury's Bell Harry Tower to allow the camera to track up to and through them. The bells were "rung" by bell ringers from the Cathedral, who pulled the strings with finger and thumb to a playback of the real bells.
On September 19, 2007, this film became the first ever to be projected to an audience in Canterbury Cathedral and was shown as a fund-raising event to pay for repairs to the cathedral caused by WW2 bomb damage.
Amongst the various books and pictures seen in Colpeper's sitting room is a photograph of the Shetland Island of Foula, the location of director Michael Powell's first acclaimed feature film, The Edge of the World (1937).
On May 11, 2014, to celebrate the 70th anniversary of the first public screening of the film on 11 May 1944, it was shown again in Chilham, one of the villages around Canterbury that went to make up the fictional "Chillingbourne" where we spend most of the film. Over 100 tickets were sold for the screening in Chilham village hall. All proceeds went to their war memorial restoration fund.
James Tamsitt had a haircut to make him look tidy before he went to London with Leonard Smith and David Todd to do some scenes at Denham Studio. Unfortunately, his new haircut didn't match the unruly mop he had in scenes filmed on location, so he had to wear a wig.
The engraving on the Colpeper Insitute plaque, "Not heaven itself upon the past has power; But what has been, has been, and I have had my hour", is from "Imitation of Horace" by 'John Dryden' (Book iii. Ode 29, Line 71).
Upon arriving in Canterbury, Sgt. Gibbs goes to the police station and asks to speak to Superintendant Hall. George Hall was the real-life Superintendant of the Canterbury Police at the time (1944). The police station was also real.
This was the first box-office flop that the team of Michael Powell and Emeric Pressburger had, and it was unseen and unavailable for many years before being rediscovered in the late 1970's. It was only after that, that people began to question whether or not Stanley Kubrick had seen it prior to making his famous success, "2001 - A Space Odyssey". Certainly, the opening of this film, where a falcon is released from a falconer's wrist in the 14th-century prologue, flies into the air out of shot and seems to turn into a World War II RAF plane as the modern sequences that take up the rest of the film begin, is very similar to the famous moment in "2001" where a bone, flung into the air by the prehistoric ape-man Moonwatcher at the end of the film's first section, is transformed by a single cut into a space-craft moving through space, to usher in the second section, set some four million years later. Neither Kubrick nor Powell ever confirmed this apparent influence.