In their research, Clement and La Frenais spoke to Jonathan Marshall, a former prisoner who had written a book, "How to Survive in the Nick", and he advised them about prison slang, dress and routines. Struggling to think up plots and humour for such a downbeat, confined environment, a particular phrase used by Marshall – "little victories" – struck a chord and convinced them to base the series on an inmate who made his daily life in prison more bearable by beating the system, even in trivial ways.