The Mental Health Act 1983 (c.20) is an Act of the Parliament of the United Kingdom. It covers the reception, care and treatment of mentally disordered people, the management of their property and other related matters, forming part of the mental health law for the people in England and Wales. In particular, it provides the legislation by which people diagnosed with a mental disorder can be detained in a hospital or police custody and have their disorder assessed or treated against their wishes, informally known as "sectioning". Its use is reviewed and regulated by the Care Quality Commission. The Act was significantly amended by the Mental Health Act 2007. A white paper proposing changes to the act was published in 2021 following an independent review of the act by Simon Wessely.