 Although in the book on which the film is based, McVicar was in  prison with many infamous criminals of his day, the majority of  characters in the film have fictitious names. For example, the  character of Cody is based on the notorious Moors Murderer Ian  Brady, and his girlfriend, mentioned during the riot scenes (as  McVicar and others read the transcription from Codys trial), is  Myra Hindley.