This article aims to contribute to an understanding of the Mental Health Act 2007, which came into force in November 2008. The article explains the link between the Mental Health Act, the Mental Health Act Code of Practice and mental health case law. It describes the guiding principles outlined in the Code of Practice, identifies the nine major changes to the Mental Health Act 1983 and discusses the role of the nurse in the care and treatment of people subject to the Mental Health Act 2007.