An autobiographical novel by Julia Steel recounts a year in the life of a probation officer working in London in 1945. The unpublished manuscript, written in the mid-1950s, provides a rare contemporary glimpse into the lives and social regulation of a group of families living on a housing estate at the end of the Second World War. Steel herself was a wartime graduate of the Cromwell Road Home Office Training Centre. This article sets primary source material, including lecture notes from Steel's training course, in the context of both contemporary and recent academic and professional literature. Following the centenary year of the Probation Service in England and Wales, it aims to contribute some new insights into the history of (women) probation officers and their daily work. It argues that Steel's manuscript and lecture notes can be interpreted within an analysis of state intervention in the lives of working-class families that places professional women in a tutelary and disciplinary relationship with mothers and daughters. It concludes by demonstrating the relevance of such an analysis to our understanding of the gendered nature of work in the Probation Service in England and Wales.