In order to create a realistic bond between the leading actresses, director Michael Caton-Jones sent them on a two-week bender in Scotland, which included various open bus tours and a trip to a Bavarian beer hall.
Began filming without a title. It was known from the beginning it would not be titled "The Sopranos", the name of the Alan Warner novel it's based on, to avoid confusion with the TV series Die Sopranos (1999). The title that was eventually chosen is a shortening of the name of the girls' school, Our Ladies of Perpetual Succour. Lee Hall used the full name for the title of his 2015 stage play adaptation of the novel.
Michael Caton-Jones had already optioned to adapt the original novel in 1998. It took 20 years for him to begin production on this film. By the time filming began in 2018, his co-writer, Alan Sharp, had been dead for over five years.