Abstract: This aim of this thesis was to explore and describe registered nurses' experiences of undertaking the statutory role of Responsible Clinician under the Mental Health (Compulsory Assessment and Treatment) Act 1992. The role of Responsible Clinician has been available to nurses since 1992 yet to date there has been little research into nurses' experiences of undertaking this role. An exploratory descriptive approach was therefore used in this study. A convenience sample of four nurses who had been undertaking the role of Responsible Clinician was recruited. Their experiences were elicited through in-depth interviews. Analysis of the interview material revealed the themes of legitimacy, relationships, expanding practice, responsibility and accountability, approaches to care, nurses' responsiveness to the role and support of the role. The author points to this research being important to nurses who are working in the psychiatric mental health area so that they can understand the role more fully. In this way, more nurses may choose to undertake the role of Responsible Clinician.