This paper revisits and reassesses the intellectual and practical contribution of Caroline Benn (née DeCamp, 1926-2000) to politics, policymaking and practice at a crucial turning point in English education, which I call the 'long comprehensive moment' between 1950 and 1990. It articulates a strong sense that her involvement in significant public events warrants close investigation before it disappears from professional memory. The American wife of Tony Benn, one of the most influential post-war socialists in Europe, Caroline Benn stands out for her commitment to an educational system in which all young people could develop their talents to the full. Based on her newly available archive, containing thousands of documents, historically informed network ethnography is used to map her on-going effort and provide a detailed descriptive account of the ideological power and pervasiveness of the idea that a school system designed for an elite is not about social engineering, whereas comprehensive education which values all children, all parents, all neighbourhoods, equally is.