Diversion from custody refers to arrangements that allow the transfer of mentally disordered offenders from the criminal justice system to mental health facilities, whether hospital or community based. The aim of diversion is to ensure that mentally disordered offenders receive health and social care in suitable facilities (Riordan et al. 2000). Diversion mechanisms have existed for over two centuries (Birmingham 2000), but in 1990, the Home Office issued a directive that paved the way for establishing a large number of police and court diversion schemes across England and Wales. This document – Home Office Circular 66/90 – encouraged cooperation between criminal justice, health and social services to ensure that those suffering from mental disorder received appropriate care and treatment, whether or not proceedings were brought.