The Mental Health Act 2025: what changes, and when

Where the 2025 Act came from

It grew out of the 2018 Independent Review, and DHSC says it takes forward the vast majority of the Review's recommendations. The Bill started in the House of Lords on 6 November 2024, finished its Lords stages on 23 April 2025 and went to the Commons the next day.

The new detention test: serious harm

For s2, there will have to be a risk that serious harm may be caused to the health or safety of the patient or someone else unless they're detained. Given the nature, degree and likelihood of that harm, the patient must also be someone who ought to be detained (2025 Act s5).

For section 3 and its renewal, the harm test is the same, and treatment must be necessary given the nature, degree and likelihood of the harm. It must be impossible without detention, and appropriate treatment must be available. The nurse's s5(4) holding power gets the serious harm test too.

The draft Bill also asked how soon the harm might happen. That part was dropped.

Appropriate treatment and therapeutic benefit

A new s1A will define appropriate medical treatment. It must have a reasonable prospect of alleviating, or preventing the worsening of, the disorder or one of its symptoms or manifestations. It must also be appropriate in the person's case (2025 Act s8).

SOAD certificates under ss57, 58 and 58A will then certify that the treatment is appropriate medical treatment in that sense. So the therapeutic benefit test follows the patient into Part 4.

Autism and learning disability

Once commenced, s3, CTOs and s3 renewals will need a psychiatric disorder, meaning a mental disorder other than autism or learning disability (2025 Act Sch 1). An autistic person or someone with a learning disability could still be detained under s2 for up to 28 days, or under Part 3.

The Act also puts care (education) and treatment reviews into law, requires ICBs to keep dynamic support registers, and gives commissioners new duties (new Part 8A). DHSC will commence the s3 change only when strong community services are in place.

The nominated person

• Chosen by the patient. In writing, signed in front of a health or care professional or an IMHA. The witness confirms they've no reason to suspect incapacity, fraud or undue pressure (new Sch A1 para 3).
• Old enough. The nominated person must be 16 or over, or 18 or over if the patient is under 16 (para 2).
• If the patient can't choose. An AMHP can appoint one for a patient who lacks capacity or competence and hasn't chosen anyone (para 7).
• Consulted, and able to object. An AMHP will have to consult them before applying for s3 or guardianship, and they'll be able to object (new s11(4) and (4B)).
• Removable by a court. The county court can end an appointment on set grounds, such as an unreasonable objection or unsuitability (new s30B).

How the current rules work is set out under the nearest relative.

New treatment safeguards

• A clinical checklist. Once commenced, the AC in charge of every Part 4 decision will have to consider alternatives, help the patient take part, and weigh their wishes, feelings, beliefs and values. They must consider the views of the nominated person, any IMHA, attorney or deputy, and carers (new s56A).
• A compelling reason. Medication refused by a patient with capacity will need a SOAD and a compelling reason, at any point in the detention. So will medication that conflicts with a valid advance decision or an attorney's, deputy's or court's decision (new s57A).
• What counts as compelling. There's no alternative appropriate treatment, or the patient hasn't consented to any alternative either (new s57A(4)).
• Certificates at two months. In other cases, the medication certificate will be due after two months, not three (2025 Act s14).
• Urgent treatment. Alleviating serious suffering will no longer justify treating a patient with capacity against their refusal (2025 Act s17).

Today's rules are under consent to treatment.

What's in force on 29 October 2026

Section 56 brought in the first two groups automatically. Everything else needs commencement regulations, and SI 2026/385 is the only set made so far.

Supervised discharge

A restricted patient can now be conditionally discharged on conditions that amount to a deprivation of liberty. The Justice Secretary must be satisfied they're necessary to protect the public from serious harm (s42(2A)). The tribunal can do the same, on a test that also weighs the patient's mental health (s73(2) and (5A)).

It reverses SSJ v MM for restricted patients. MoJ's guidance calls it the last option, not a stepping stone. Its definition of deprivation of liberty still uses the acid test that AGNI overruled. See conditional discharge and recall.

Wider section 48 transfers

Section 48 already reached Immigration Act 1971 detainees. It now also reaches people detained under s36 of the UK Borders Act 2007 or the saved EEA Regulations (2025 Act s36(3)(b)). It also reaches children remanded to youth detention accommodation under s91 of the Legal Aid, Sentencing and Punishment of Offenders Act 2012 (2025 Act s38).

The new treatment condition for ss47 and 48, that appropriate treatment can be given for the relevant disorder, isn't in force yet. See urgent transfer under s48.

The human rights duty on private providers

Since 6 April 2026, registered care providers count as public authorities under the Human Rights Act for some services (s142C). They are s117 aftercare, and inpatient assessment or treatment for mental disorder that the NHS arranges or pays for.

That includes informal patients. Section 142C extends across the UK, and covers the equivalent Scottish aftercare too (s142C(2)(b)).

The review of CQC notifications

Section 52 makes the Secretary of State review when CQC must be told that someone under 18 is an inpatient being assessed or treated for mental disorder. The report must be laid and published within two years of Royal Assent.

Using the 1983 Act as it stands

When you read the revised 1983 Act on legislation.gov.uk, the uncommenced 2025 amendments appear as outstanding changes, not in the text. Your criteria, forms, nearest relative rules and detention periods are all still the current law.

Why the reforms are phased

DHSC splits them by cost. Phase 1 holds the reforms that come at little or no extra cost or burden on the workforce. The later ones need more funding, more staff or new infrastructure before they can start safely (DHSC, March 2026). Nothing in the Act fixes those dates; they're DHSC's indicative plan (s56(3)).

What Phase 1 will mean in practice

If DHSC's plan holds, Phase 1 brings in the serious harm and therapeutic benefit tests, and a nominated person in place of the nearest relative. The clinical checklist may come then too, but DHSC hasn't said which treatment reforms are in Phase 1.

Only the treatment reforms that don't add to the SOAD workload are in Phase 1. DHSC will publish the updated Code and the secondary legislation alongside it.

The nominated person will take over the nearest relative's roles and gain new ones. The RC must consult them before making a CTO. If they object, the CTO needs the RC to certify that the patient would otherwise be likely to act dangerously (new s17AA).

Why some changes wait until after 2029

These are the reforms that need money, staff or infrastructure. The autism and learning disability change to s3 is the clearest: DHSC will commence it only when strong community services exist to support people instead.

Until each reform is commenced, the 1983 rule it replaces still applies. For s3, that means autism, or a learning disability with the qualification, can still found a detention.

The 28-day prison transfer limit

DHSC aims to commence it by December 2027, two years after Royal Assent. It starts with the first request for a medical report, for a sentenced prisoner (new s47A) or anyone else s48 covers (new s48A). The referring body must then notify the Secretary of State, the prison governor or other detention authority, and the NHS bodies likely to be involved (new s47A).

Absent exceptional circumstances, they must then seek to ensure a transfer decision is made, and any transfer completed, within 28 days. A shortage of beds or staff isn't exceptional. See prison transfer under s47.

How each reform will start

Everything not yet in force needs regulations made by the Secretary of State, and different parts can start on different days (2025 Act s56(3) and (5)). Each set of regulations will say which provisions start, and when.

Expect dates to move. Earlier forecasts put the first major reforms in 2027 or 2027/28, and that has slipped to 2028/29.

What to watch

• Commencement regulations. On legislation.gov.uk, as the Mental Health Act 2025 (Commencement No. 2) Regulations.
• The draft Code consultation. On GOV.UK among DHSC's consultations, indicatively early 2027.
• Ministerial statements. Written statements in Hansard on implementation.
• MoJ's supervised discharge guidance. A revision to reflect AGNI.

Why a new Code is needed

The 2025 Act rewrites s118(2B), so the Code must address four new principles (2025 Act s1). See the current guiding principles for the five it replaces.

It also widens who the Code guides. Once commenced, it will guide nominated persons and the professionals who witness their appointment, IMHAs, CQC's Part 4 functions, and NHS bodies on advance choice documents.

What DHSC says it will change

• New law. Fresh guidance for the new powers and duties.
• The principles throughout. Embedded across the Code, especially at key decision points.
• Specific groups. Racial disparities, and the needs of groups such as children and young people.
• Out-of-date parts. Refreshing chapters that have dated, such as the one on the Care Programme Approach.
• Wider commitments. Changes promised in the White Paper and in Parliament that don't need legislation.

Expect new guidance on the new duties, such as nominated persons, the clinical checklist, care and treatment plans, advance choice documents and opt-out advocacy. DHSC says it will consult extensively, and wants to hear from frontline staff.

How it becomes final

The Secretary of State must consult the bodies concerned (s118(3)). The Code is then laid before Parliament, and either House can resolve to withdraw it within 40 days (s118(4) and (5)).

DHSC plans to consult publicly on the draft, indicatively in early 2027. It intends to publish the final Code alongside the Phase 1 reforms.

What about Wales?

The 2025 Act writes the Welsh Ministers into s118 as the authority for the Code for Wales, laid before the Senedd, and applies the same principles there (2025 Act s2). The Senedd can resolve to withdraw it within 40 days, as either House of Parliament can for England (s118(5A) and (5B), as inserted). Until the Welsh Ministers revise it, Wales keeps its own 2016 Code.

Until then: the 2015 Code, with care

You must still have regard to the 2015 Code. Know where it has dated. It describes the Cheshire West acid test (Code 13.44), which AGNI overruled, and DHSC says parts such as the Care Programme Approach chapter are out of date. It also still refers to clinical commissioning groups (Code 14.78), while the Act now refers to integrated care boards.

The 2015 Reference Guide is dated too. It still gives 72 hours for ss135 and 136, which are now 24 hours, extendable by 12.

Read the Code alongside what has come since. That includes the 2017 guidance on police powers and places of safety, and the 2021 statutory guidance under the Mental Health Units (Use of Force) Act 2018.