SummaryWith the subspecialisation of psychiatry in the UK, clinicians encounter problems at the interfaces between specialties. These can lead to tension between clinicians, which can be unhelpful to the clinical care of the patient. This article focuses on the interface between general and forensic psychiatry in England and Wales. The pattern of mental health services in England and Wales differs to an extent from those in Scotland, Northern Ireland and in the Republic of Ireland. Consequently, the interface between general and forensic psychiatry is subject to varying influences. Important interface issues include: the definition of a ‘forensic patient’; the remit and organisation of services; resources; clinical responsibility; and care pathways. This article also discusses a general overview of how to improve collaboration between forensic and general adult psychiatric services.Learning Objectives•Develop an understanding of important issues at the forensic/general adult psychiatry interface.•Be aware of areas of conflict that may arise at the forensic/general adult psychiatry interface.•Be aware of options for optimum cooperation at the interface.