The intervention will be run in two 60-minute sessions per week for 12 weeks. All sessions will include a” healthy living” education component, designed to encourage motivation and behaviour change. All young people will receive their usual care as planned by the referring service. Exercise sessions will be delivered by Registered Exercise Professionals (REPs) sought from local CSPs, supported by mental health support workers (MHSWs) sought from an identified local NHS organisation. The research team will collect data from the young people at baseline, and at 3, 6 and 12 months. This will include questionnaires on depression, quality of life, sleep, self-esteem, service use, impact on families, medical conditions & medication, session attendance and physical activity. The researchers will interview some young people, parents/carers, REPs and MHSWs to understand their experience of the exercise sessions, participation, referral pathways and programme.