During the last decade the planning of services for offenders with mental disorders in the United Kingdom has been geared toward diverting them from the criminal justice system to appropriate levels of psychiatric and social care. Although a seamless service system is yet to be developed, the central government has made a concerted effort to promote a better understanding of the needs of offenders with mental disorders and encourage collaboration between the relevant agencies. A major program of research has been initiated, and local health authorities have been encouraged to use a consortium approach to planning and delivery of specialist services. The authors discuss the activities of the Wessex consortium, composed of five local health authorities and a social services department serving a catchment area with a population of 2.5 million in southern England. The consortium has commissioned needs assessments for all offenders with mental illness from the catchment area and a survey of the resources for secure residential treatment in the region. Based on data from this research, the consortium is planning the development of two long-stay secure units to accommodate offenders with a history of repeated inpatient and prison stays and poor response to previous treatment and rehabilitation efforts.