What is the Mental Health Act 1983?
It's the law in England and Wales for the reception, care and treatment of people with a mental disorder (s1(1)). It received Royal Assent on 9 May 1983 and came into force on 30 September 1983 (s149). Only a few sections reach Scotland or Northern Ireland, which have their own laws.
Its roots are in the Mental Health Act 1959, which Lady Hale called the foundation of modern mental health law (MM [6]). The 1983 Act you use today is that law as amended, mainly in 2007.
Who does it apply to?
Anyone with a mental disorder, meaning any disorder or disability of the mind (s1(2)). There's no minimum age for detention in hospital (Code 19.17), though children and young people get extra protections.
It reaches people in hospital, in the community on a CTO or guardianship, and in the courts and prisons under Part 3. A few parts cover informal patients too, such as the rules for 16- and 17-year-olds (s131) and the human rights duty on private providers (s142C).
The main powers in plain words
| What it does | How long | |
|---|---|---|
| Section 2 | Admission for assessment, and treatment if needed | Up to 28 days |
| Section 3 | Admission for treatment | 6 months, then 6, then a year at a time |
| Section 4 | Emergency admission on one medical recommendation | 72 hours, unless a second arrives |
| Section 5(2) and 5(4) | Holding an inpatient while an assessment is arranged | 72 hours (doctor or AC); 6 hours (nurse) |
| Sections 135 and 136 | Police powers to take someone to a place of safety | 24 hours, extendable by 12 |
| CTO and guardianship | Care in the community, on conditions or a guardian's powers | 6 months, then 6, then a year at a time |
| Part 3 | Court and prison routes into hospital | Depends on the order |
Most detained patients can be treated for mental disorder without consent (s63). Medication after three months and ECT need extra certificates, and the short-term holding powers don't allow it (s56). Every power, with its criteria and forms, is in the sections at a glance.
What did the 2007 amendments change?
The Mental Health Act 2007 amended the 1983 Act rather than replacing it. Most changes started on 3 November 2008.
- One definition of mental disorder. Any disorder or disability of the mind, with the learning disability qualification and the alcohol and drugs exclusion (s1). See what counts as mental disorder.
- Appropriate medical treatment. Section 3 now needs appropriate treatment to be available for the patient (s3(2)(d)).
- New professional roles. AMHPs, drawn from several professions (s114), and approved and responsible clinicians, who needn't be doctors.
- CTOs and ECT safeguards. Community treatment orders (ss17A to 17G), and a separate regime for ECT (s58A).
- IMHAs and age-appropriate care. Advocacy for qualifying patients, in England from April 2009 (s130A), and a duty to provide suitable environments for under-18s, from April 2010 (s131A).
- DoLS. It also added the deprivation of liberty safeguards to the MCA, from 1 April 2009.
The Act and its Code of Practice
The 2015 Code, in force since 1 April 2015, is statutory guidance made under s118. You must have regard to it, and depart from it only with cogent reasons that you record (s118(2D); Munjaz). Wales has its own Code, from 2016.
Some guidance has dated. The Code still describes the Cheshire West acid test (Code 13.44), which AGNI overruled in June 2026. The 2015 Reference Guide gives the old 72-hour limit for ss135 and 136; it's now 24 hours, extendable by 12.
Mental Health Act 1983 vs Mental Capacity Act 2005
| Mental Health Act 1983 | Mental Capacity Act 2005 | |
|---|---|---|
| What it's for | Assessing and treating mental disorder | Any decision someone lacks capacity to make |
| Capacity | Not the test: it can override a capacitous refusal | The gateway: it applies only if they lack capacity |
| Age | No minimum age | 16 and over, with some parts from 18 |
| Deprivation of liberty | Detention in hospital under its own sections | DoLS in hospitals and care homes, or a court order |
| Main safeguards | Tribunal, SOADs, IMHAs, nearest relative | Best interests, IMCAs, the Court of Protection |
The MCA can't authorise treatment for mental disorder that Part 4 of the MHA regulates (MCA s28). An objecting patient who meets s2 or s3 and needs hospital treatment for mental disorder can't be put on DoLS (MCA Sch 1A). MHA or MCA? helps you choose.
What's changing
The Mental Health Act 2025 amends the 1983 Act. Only supervised discharge, wider s48 transfers and the human rights duty on private providers are in force so far. The revised 1983 Act shows the rest as outstanding changes.
DHSC plans a consultation on a draft Code, indicatively in early 2027, and expects the first major reforms in 2028 to 2029. See what the 2025 Act changes, and when.
The Mental Health Act 1983, Part by Part
The 1983 Act consolidated the law on mentally disordered people. It was heavily amended in 2007 and is being amended again by the 2025 Act. At its core it lets the state assess and treat people for mental disorder without their consent, in hospital or on conditions in the community. The rest of it builds the safeguards around that power.
Two ideas run through it. Detention needs criteria, not a diagnosis: a disorder of a nature or degree, a reason to intervene, and for longer detention appropriate treatment that's actually available. And the safeguards grow with the intrusion. A 72-hour holding power has almost none. Detention for treatment brings the tribunal, second opinions and aftercare.
Most of what you'll use day to day sits in Parts 2, 3, 4 and 10. The Code of Practice (s118) tells you how to use the Act, and the Reference Guide sets out what it says.
Part 1What counts as mental disorders1
One section, and an important one. Mental disorder is any disorder or disability of the mind. Dependence on alcohol or drugs isn't one on its own. A learning disability only counts for the longer-term powers if it comes with abnormally aggressive or seriously irresponsible conduct.
On this site: What counts as mental disorder, and the MHA guiding principles
Part 2Civil detention, guardianship and the nearest relativess2 to 34
The civil powers. Admission for assessment (s2), for treatment (s3) and in an emergency (s4). The holding powers for inpatients (s5). Guardianship (ss7 to 10). How applications and medical recommendations must be made (ss11 to 15). Leave (s17), CTOs (ss17A to 17G), patients (ss18 and 21), renewal (s20) and discharge (ss23 and 25). Finally the nearest relative, who they are and how a court can replace them (ss26 to 30).
s2s3s4s5s7s11s12s17s17As20s23s26s29
On this site: Section 2 of the Mental Health Act: admission for assessment · Section 3 of the Mental Health Act: admission for treatment · Section 4 of the Mental Health Act: emergency admission · Section 5(2) and 5(4): holding powers under the Mental Health Act · Mental Health Act assessment: how an application is made · The nearest relative under the Mental Health Act · Section 17 leave under the Mental Health Act, and going AWOL · Community treatment orders under the Mental Health Act · Guardianship under the Mental Health Act: section 7 · Section 3 renewal, discharge and hospital managers' hearings
Part 3Patients in criminal proceedings or under sentencess35 to 55
How courts and the prison system use the Act. Remands to hospital (ss35 and 36). Hospital and guardianship orders (ss37 to 40). Restriction orders and the Justice Secretary's powers (ss41 to 45). Hospital and limitation directions (ss45A and 45B). Transfers from prison (ss47 to 53). Schedule 1 says which Part 2 rules apply to these patients and which don't.
s35s36s37s38s41s42s45As47s48s49
On this site: Forensic sections: Part 3 of the Mental Health Act · Section 37 hospital orders: criteria, length and discharge · Section 37/41: hospital orders with a restriction order · Section 47/49: transferring sentenced prisoners to hospital
Part 4Consent to treatmentss56 to 64
The rules for treating detained patients. Section 56 says who covers. Section 63 lets you treat mental disorder without consent. Sections 57, 58 and 58A add certificate rules for neurosurgery and hormone implants, for medication after three months, and for . Section 62 covers emergencies, and ss59 to 61 deal with treatment plans, withdrawn consent and review.
On this site: Section 58 and consent to treatment under the Mental Health Act · ECT under the Mental Health Act: section 58A and emergency ECT
Part 4ATreating CTO patients in the communityss64A to 64K
Treatment for someone on a who hasn't been recalled. A capacitous refusal stands. Someone who lacks capacity can be treated if they don't object, or if they object but no force is needed. Force is for emergencies only. Medication needs a CTO11 or CTO12 certificate once the CTO's first month and the original three-month period have both passed.
On this site: Community treatment orders under the Mental Health Act
Part 5Tribunalsss65 to 79
Who can apply to the tribunal and when (ss66, 69, 70 and 75). When the managers or the Secretary of State must, or may, refer a case (ss67, 68 and 71). What the tribunal can do: discharge, defer, recommend (ss72 to 75). In England that's the First-tier Tribunal (Mental Health); Wales has its own Mental Health Review Tribunal.
On this site: The Mental Health Tribunal: how it works, and your report
Part 6Moving patients around the UKss80 to 92
Part 7Repealedss93 to 113
The old Court of Protection powers over patients' property and affairs. They were repealed and replaced by the Mental Capacity Act 2005.
On this site: The Mental Capacity Act 2005: what it does and who it covers
Part 8Councils and the Secretary of Statess114 to 125
approval, training and powers of entry (ss114 to 115). Aftercare (s117). The Code of Practice (s118). Second opinion doctors and 's job of protecting detained patients (ss119 and 120).
On this site: Section 117 aftercare under the Mental Health Act · Responsible clinicians, AMHPs and the other Mental Health Act roles
Part 9Offencesss126 to 130
Forging or falsifying documents, ill-treatment or wilful neglect of patients by staff (s127), helping a patient go absent, and obstructing people acting under the Act.
Part 10Everything else that matters on the wardss130A to 149
IMHAs (ss130A to 130L). Informal admission, including 16 and 17-year-olds, and suitable wards for children (ss131 and 131A). Information for patients and relatives (ss132 to 133). Correspondence (s134). Police powers and places of safety (ss135 to 136C). Protection for people acting in good faith and with reasonable care (s139). The human rights duty on private providers (s142C). The definitions, including medical treatment (s145).
On this site: Patients' rights under the MHA: section 132 and IMHAs · Informal admission: informal patients and their rights · Section 136 and section 135 of the Mental Health Act: police powers
The law around the Acts
Neither Act works alone. These are the other pieces of law you'll meet, and where they bite.
ECHRConvention rightsHuman Rights Act 1998
Article 5 is the big one. It allows detention of people of "unsound mind" only on three conditions (Winterwerp, 1979). Objective medical evidence reliably shows a true mental disorder, it's of a kind or degree that warrants confinement, and it persists. Article 5(4) requires a speedy review by a court, and the tribunal provides it. Article 2 protects life (Rabone). Article 3 bans inhuman or degrading treatment, and can be engaged by restraint and seclusion. Article 8 protects private and family life. Public bodies must act compatibly, and since April 2026 so must private providers of NHS-funded inpatient mental health care and s117 aftercare.
On this site: Key cases in mental health law, from Bournewood to AGNI
Children Act 1989Children and families
Parental responsibility, accommodation by the council (s20), care orders (s31) and secure accommodation (s25). The Children's Wellbeing and Schools Act 2026 will extend s25 to "relevant accommodation", with the court authorising.
On this site: Children and young people: Gillick competence, the MCA and the MHA
Care Act 2014Social care and safeguarding
Needs assessments and adult safeguarding enquiries (s42). It also decides which council is responsible for s117 aftercare, through ordinary residence.
On this site: Section 117 aftercare under the Mental Health Act
Criminal lawFitness, insanity and diminished responsibility
The Criminal Procedure (Insanity) Act 1964 governs unfitness to plead, the wording of the special verdict required by the Trial of Lunatics Act 1883, and the disposals after both. The Homicide Act 1957, s2, sets the test for diminished responsibility.
On this site: Fitness to plead: criteria, assessment and procedure · The insanity defence and automatism in England and Wales · Diminished responsibility in England and Wales: the four-part test
Other ActsSmaller Acts that change practice
The Mental Health Units (Use of Force) Act 2018 governs restraint, and the Policing and Crime Act 2017 reshaped ss135 and 136. The Mental Capacity (Amendment) Act 2019 created the Liberty Protection Safeguards, which aren't yet in force.
On this site: Restraint in mental health: the Use of Force Act 2018 and the Code · Section 136 and section 135 of the Mental Health Act: police powers · The Deprivation of Liberty Safeguards (DoLS) explained
Questions trainees ask
Is the Mental Health Act 1983 still in force?
Yes. The Mental Health Act 2025 amends it rather than replacing it, and almost none of the 2025 changes are in force yet. The 1983 Act and the 2015 Code of Practice are the law you use, and the law the MRCPsych examines.
What's the difference between the Act and the Code of Practice?
The Act is the law. The Code, made under s118, is statutory guidance on how to use it. You can depart from it only with cogent reasons, and you should record them.
What does the Mental Health Act 1983 do?
It lets people with a mental disorder be detained, assessed and treated without their consent when strict criteria are met, and supervised in the community. It also sets the safeguards: the tribunal, second opinions, advocacy and aftercare.
What did the Mental Health Act 2007 change?
It amended the 1983 Act, mostly from 3 November 2008. It brought in the single definition of mental disorder, the appropriate medical treatment test, AMHPs, approved and responsible clinicians, CTOs and IMHAs, and added to the .
Which sections of the Mental Health Act give the police powers?
Section 135, a magistrate's warrant to enter premises, and s136, which lets an officer take someone from anywhere except a home to a place of safety. Both allow up to 24 hours, extendable by 12.
What's the difference between the Mental Health Act and the Mental Capacity Act?
The is for assessing and treating mental disorder, and can override a capacitous refusal. The MCA covers any decision that someone aged 16 or over lacks capacity to make, and can't authorise treatment that of the MHA regulates (s28).
How do I reference the Mental Health Act 1983?
Use its short title and chapter number, Mental Health Act 1983 (c. 20), and name the section you mean. If you quote the amended wording, say you used the revised text on legislation.gov.uk and give the date you read it.