This article describes a service development aimed at increasing access to cognitive behaviour therapy (CBT) for a detained inpatient population in an established medium secure forensic hospital. The 76-bed unit is part of the forensic division of an NHS trust. The hospital provides assessment and treatment for mentally disordered male offenders, the majority of whom have a diagnosis of schizophrenia. The initial development and core functions of the CBT link nurse role are described in detail, and the outcomes and limitations of the role are discussed, along with suggestions for continued research.