The title, in British police parlance of the day, defines a petty crook whose criminal activities are minor and legal-borderline, but the title character in this film appears to stretch the definition. Benny steals a purse from Caroline and discovers a compromising letter in it from her boyfriend Mannering, who is a wealthy surgeon and married. Benny starts a blackmail campaign that leads to murder.
—Les Adams <longhorn1939@suddenlink.net>