This article describes a Rapid Assessment Exercise commissioned by a local authority to inform an evidence-based multi-agency response to the involvement of vulnerable children and younger adolescents in illicit drug trafficking. The research was commissioned by a local authority in an English County Town, The researchers analysed relevant quantitative data held by social welfare, health, educational and criminal justice agencies. Interviews were conducted with professionals from these agencies and three key informants previously involved in the illicit drugs trade. Two focus groups were conducted with professionals and three with gang-involved and gang-affected children and young people. The quotations in this article were all derived from these individual interviews and focus groups. The article considers whether the emergence of this problem is simply a result of local contingencies or whether it represents an instance, and a moment, in the evolution and transformation of, the English street gang and the ‘County Lines’ model of drug distribution. In an attempt to answer this question the article considers three models of gang and drug market evolution and assesses their relevance to developments in the Town.