This article describes the development of the primary mental health worker (PMHW) role within Child and Adolescent Mental Health Services (CAMHS) within the UK, and focuses on services in Leicester, Leicestershire and Rutland, an area with a general population of 900,000. The concept behind the PMHW role is described and the application of this to practice is outlined. The role consists of consultation, liaison, direct work and training. The described primary mental health team comprises 13 PMHWs and is an integral part of a comprehensive CAMHS. Its aim is to support and enable primary care professionals in their work with mental health issues in children and families, thus promoting early recognition and management of child mental health problems and filtering appropriate referrals for specialist CAMHS intervention.