Often linked to the Ruth Ellis case, the novel and script were written two years before her trial and hanging, according to director J. Lee Thompson's biography. The resemblance was said to be coincidental.
Director J. Lee Thompson was married to the writer of the book this film is based on, Joan Henry. They met whilst Thompson was filming Young and Willing (1954) which was also based on a novel by Joan Henry.
The calendar in which Mary has circled the days she expects to be her execution has 16 April falling on a Monday. This means the movie is set in 1951.
The poem Mary Hilton reads from "A Shropshire Lad" by A.E. Housman is "Loveliest of trees the cherry now", published in 1896.
Lucy's car is a 1955 Ford Thunderbird with a temporary import "Q" license plate.