Dutch forensic psychiatry provides services for mentally disordered offenders which centre around a legal measure called the TBS order. Specialised units deal separately with assessment and treatment. The system appears to work in the context of a small and wealthy country and a criminal justice system which differs from the English system. This paper describes the key features of the secure units, examines the conceptual issues and complications of the Dutch system, and considers lessons for psychiatric and legal approaches to the problem of psychopathy in Britain, in particular the new hybrid order.