This article provides an analysis of the role of the Advisory Council on the Treatment of Offenders in the provision of policy advice to the government in the years after the Second World War and highlights the role of its women members, who mainly owed their appointment as advisors to their expertise gained in the voluntary role of Justice of the Peace. The article first contrasts the voluntary workers' supposedly 'amateur' status with the mainly 'professional' credentials of the Council's other members and the relevance of the conventional distinctions made between the two types of experience is questioned. There follows an evaluation of the Council's impact on criminal justice policy in the period 1944-64. The article concludes that the clearest case for the Council's effectiveness can be made with regard to its early years but that the replacement of 'amateur' policy advice by criminological research in the post-1945 era was by no means a sudden process, and certainly not one that was completed by the 1960s. It suggests that in the light of the formation of Britain's first peace-time coalition government in nearly 80 years, the time might be ripe for a reconsideration of the role of voluntary sector representatives in the provision of policy advice. (Published Abstract) Figure and references