Summary StopSIM is a coalition of mental health service users and allies who have grave concerns about the rapid, widespread rollout of the High Intensity Network’s ‘Serenity Integrated Mentoring’ (SIM) intervention across NHS England. The intervention is designed for people who have not committed a crime, but are in contact with mental health services, are frequently at high risk of suicide and self harm and are deemed “high intensity users” of emergency services. Key intervent