When Sparkes calls Mrs. Hughes from the employment agency, she begins dialing the phone with the writing end of her pencil. In the next shot she's dialing with the eraser end.
When Julia initially escapes the house, she flees down a long driveway that curves out of sight of the house. When she gets to the gate, there appears to be the gatekeeper's house behind the gates. Later, Julia looks out the window of the main house down at the gate, which appears to be about thirty yards away. This is the only scene in which director Joseph H. Lewis merges the gatekeeper's house with the main house. The rest of the movie, Julia is in the main house, which is distant from the front gates.
Julia places the rent money in Bertha's left hand between the folds of an envelope with the stamp on top and the cash accessible from the right side. The next shot shows Bertha holding the envelope in her right hand with the position reversed and the cash accessible from the left of the folded envelope.
When Julia Ross gets the letter from Dennis Bruce at the beginning of the film, the close-up of the hands holding the envelope show grown nails with dark nail polish. When the film cuts back to a wide shot of her opening the envelope and reading the letter, her nails have no nail polish, are bitten down and have dirt under the edges.
The number/license plates on the cars do not match the pattern of English cars at any time.
In the film's second scene in which Julia (Nina Foch) is speaking to the charwoman, she is holding a newspaper. The crossword on the page facing the camera is in US, not English, format.