Prisons, prisoners and prison officers go back a long way before the formation of the Prison Officers’ Association in September 1939. This text charts the development of this association, the evolution of the terminology used to describe prison officers (formerly known as ‘wardens’ and ‘gaolers’) and the role of the prison officer in the modern day. This comprehensive history is one of the first of its kind, presenting the story of a union that has not received much attention in the past.