Although this film is in English, the US release has English subtitles because all the characters speak in a very heavy Scottish accent.
The canal featured in the film was specifically built for the movie as all the already existing canals were either too polluted or too clean-looking to be used for the film.
The shot of James pulling his shoe from the canal is actually a reversed shot of the shoe being submerged.
The title of the film is taken from a newspaper headline, "The Ratcatcher!"