AbstractThis article explores interwar penal policy tensions through a case study of Harold Jones, a sexually sadistic double child‐killer. Reports by two reforming Prison Commissioners of that period – Alexander Paterson and Dr W. Norwood East – are used to develop the case study. Their different approaches to understanding Jones's offences reflect their conflicting views on the aetiology of crime, the purpose of imprisonment and how to address offending behaviour. This shaped the extent to which they were prepared to act as an advocate for Jones and whether or not he should be released. It also influenced their views on the operational management of prisons and brought them into conflict with other administrators, managers and commentators of that period, as the prison service moved slowly out of its Victorian origins and responded to the demands of the times.