What is the difference between Section 2 and Section 3?
Short answer
Section 2 is for assessment — up to 28 days, not renewable. Section 3 is for treatment — six months to start, renewable — and is used when the diagnosis and treatment are already known. Your nearest relative can block a Section 3 but not a Section 2, and only Section 3 brings free Section 117 aftercare.
Both sections detain you in hospital, and both need an application by an Approved Mental Health Professional (AMHP) backed by two medical recommendations, at least one of them from a doctor approved under Section 12 — usually a consultant psychiatrist. What separates them is purpose, length and the safeguards attached.
The practical differences
- Purpose. Section 2 is used where the nature or degree of your disorder is uncertain and clinicians need to assess it. Section 3 is used where the diagnosis and the appropriate treatment are already established.
- Length. Section 2 lasts a maximum of 28 days and cannot be renewed — before it expires you must be discharged or a Section 3 application made. Section 3 runs for six months, renewable for six months and then annually.
- An extra test for Section 3. Appropriate medical treatment must actually be available in the hospital you are admitted to, and it must be treatment that cannot be provided unless you are detained.
- Your nearest relative. They must be informed of a Section 2 but cannot stop it. For Section 3 the AMHP must consult them, and if they object the application cannot go ahead unless the County Court displaces them.
- Aftercare. Discharge from Section 3 entitles you to free Section 117 aftercare. Section 2 does not.
The Mental Health Act 2025 will eventually replace the nearest relative with a Nominated Person you choose yourself, but that reform is not yet in force — the nearest relative rules above are the law today.
Appeals and treatment rights
Your appeal rights differ too. On Section 2 you can apply to the Mental Health Tribunal within the first 14 days, and the hearing must be held within seven days of your application. On Section 3 you can apply once in the first six-month period and once in each renewal period. Legal aid for tribunal work is automatic and is not means-tested.
On either section, medication can be given without your consent for the first three months of detained treatment; beyond that a Second Opinion Appointed Doctor from the Care Quality Commission must certify that it is appropriate. Ask for an Independent Mental Health Advocate as soon as you are admitted — the service is free, and they can help you get a tribunal form and find a solicitor. Rethink Mental Illness (0808 801 0525) can also advise.
Related guides
Section 2: Admission for Assessment
Section 2 of the Mental Health Act 1983 allows a person to be admitted to hospital and detained for up to 28 days for assessment of their mental disorder (or assessment followed by treatment). It is used when clinicians need to assess the nature and degree of a person's disorder before deciding on a longer-term plan. It requires an application by an AMHP and two medical recommendations.
6 min
Section 3: Admission for Treatment
Section 3 of the Mental Health Act 1983 allows a person with a mental disorder to be admitted to hospital and treated without their consent for an initial period of up to 6 months, renewable thereafter. It is used when the diagnosis and appropriate treatment are already established. Section 3 carries significant safeguards, including the nearest relative's power to block the application.
6 min
Nearest Relative Rights Under the MHA 1983
The Mental Health Act 1983 gives a defined "nearest relative" specific rights and powers in relation to a patient's detention, including the power to discharge the patient and to object to a Section 3 application. Understanding who qualifies as nearest relative and what powers they hold is important for both patients and families.
6 min
Mental Health Tribunal Appeals
The First-tier Tribunal (Mental Health) — commonly called the Mental Health Tribunal — is the independent body that hears appeals from patients detained under the Mental Health Act 1983 in England. It has the power to discharge a patient from detention or a Community Treatment Order. Legal aid is automatically available for patients appealing to a Mental Health Tribunal.
6 min
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