Continuity mistake: Hannay is talking to the milkman inside the door. Outside the door you can see across the street, the two guys walking down the sidewalk. A moment later, Hannay goes toward the door and now there's the milk wagon on the street right in front of the door. When Hannay pointed out the two guys across the street to the milkman, the milk wagon wasn't there and the milkman is inside with Hannay so he couldn't have pulled it up.
Revealing mistake: The serial number of the autogyro has been reversed, showing that the stock shot has been reversed for effect.
Revealing mistake: During Mr Memory's act at the beginning of the film, a woman asks, "Who was the last British heavyweight champion of the world?". As she is saying this, you can see the man sitting next to her mouthing her exact words.
Character mistake: The Professor refers to his pistol as a "revolver" but it is a semi-auto.
Continuity mistake: In the apartment when Hannay discovers the dead women the telephone changes from white to green.
Suggested correction: The film is in black and white. How can you tell what color the phone is? We're you watching a colorized version? Or did you mean to post this on one of the remakes?
Factual error: Hannay travels to Scotland on The Flying Scotsman which ran from London to Edinburgh, The Forth Road Bridge is actually 12km further West of the Port of Edinburgh, so Hannay couldn't jump off the Flying Scotsman onto the Forth Bridge.
Continuity mistake: When Pamela takes off her stockings in the hotel room, Hannay dries them by placing them under two china ornaments over the fireplace. When Pamela removes the stockings from the shelf a little later on, the ornaments are now much further apart, with another ornament placed between them.
Continuity mistake: When Hannay and Pamela are hiding under the waterfall to escape the police, in a long shot Hannay's free hand is against the rock behind him, but in a close-up, the hand is in his pocket.
Other mistake: When we see the Church Hymnary being opened, the date on the left-hand page is signed by Margaret in 1928, but the book is dated 1932.
Revealing mistake: When the compere introduces Mr. Memory in the Music Hall at the start of the film, Robert Donat's stand-in is sitting in his place in the audience on at least two occasions.
Continuity mistake: When Hannay and Pamela are on the bed at the inn, Hannay asks Pamela to pass a nail file to him and you can see Hannay is about to take a bite of his sandwich. In the next shot, his hand with the sandwich is well away from his mouth.
Character mistake: During Mr Memory's act at the beginning of the film, he gives the answer regarding the last British heavyweight boxing champion and then says, "Am I right, sir?", but the question was asked by a woman.
Continuity mistake: When Professor Jordan is speaking to Hannay, he draws out a revolver with his left hand, but when the Professor's wife leaves the room, we cut back to the Professor, and he now has the revolver in his right hand.
Revealing mistake: During Mr Memory's performance at the end of the film, he stops speaking and flinches before the shot is fired.
