The UK Mental Health Act 2025: an overview of key changes the new statute will introduce

This article was co-authored by Ella Providence, Trainee Solicitor.

The UK Mental Health Bill received Royal Assent on 18 December 2025. As such, the Mental Health Act 2025 (the Act) – which amends and does not replace the Mental Health Act 1983 (the 1983 Act) - marks a significant reform and modernisation of its predecessor.

The Department of Health and Social Care has explained that the Act seeks to “ensure patients have stronger rights over their treatment through new statutory care and treatment plans”. It also aims to provide greater involvement for families and carers of patients regarding treatment decisions.

The Act retains the core principles of reform identified by Professor Sir Simon Wessely in the Independent Review of the Mental Health Act published in 2018. These principles are:

• Choice and autonomy
• Least restriction
• Therapeutic benefit
• The person as an individual.

Key legal changes 

Detention 

There will be a higher threshold for detention under the Act. Under both section 2 and section 3 of the 1983 Act, a new ‘serious harm’ test must be satisfied in that ‘serious harm may be caused to the health or safety of the patient or of another person’ and a consideration of the ‘nature, degree and likelihood’ of the harm. The Code of Practice will presumably provide a definition and guidance on what serious harm means. In addition, under section 3, people with a learning disability or people with autism must be suffering from a ‘psychiatric disorder’ which requires hospitalisation.

Compulsory treatment

The Act makes numerous changes to part 4 of the 1983 Act in relation to the provisions around treatment of detained patients. New safeguards are set to be introduced for patients with capacity who refuse treatment such as a ‘compelling reason’ requirement and a “second opinion appointed doctor (SOAD)” who will act as a second independent doctor to consider whether the recommended treatment is clinically appropriate.

Additional provisions are also there for patients who refuse electro-convulsive therapy. A SOAD will now have to certify the treatment before it is administered. This is applicable where the patient has capacity to consent or where the patient lacks capacity but has a valid advance decision in place to refuse electro-convulsive therapy.

Nominated person replaces nearest relative

The “nominated person” can be chosen by the patient at any time (provided they have the capacity or competence to do so). The “nominated person” will have the same statutory powers as the “nearest relative” but will also build on those powers and introduce additional rights in relation to consultations about care and treatment plans and the ability to object to the use of a community treatment order.

Community treatment orders (CTOs)

CTOs will require the agreement of a community clinician and will only be used if a patient is at risk of ‘serious harm’ to the health and safety of themselves or others and similar to the threshold for detention, the ‘nature, degree and likelihood’ of harm must be considered.

Learning disability and autism 

Integrated Care Boards will be required to ensure that the needs of people with learning disabilities and people with autism can be met without detention with an emphasis on increased community provisions to provide a safety net. The Act gives the requirement of a dynamic support register statutory footing.

Places of safety and interactions with the criminal justice system

Police cells are no longer acceptable places of safety for adults experiencing a mental health crisis. Prison cells will also no longer be an acceptable place of safety for people in contact with the criminal justice system. A statutory time limit of 28 days for the transfer of prisoners to hospital for treatment of a mental disorder, has also been introduced. 

Practical implementation of the Mental Health Act 2025

While, the Act became law in late 2025, commencement of the provisions of the Act will be phased. The introduction of the Code of Practice and secondary legislation is set to take place within the next year with training for the existing workforce to take place in 2026-27. The first major phase of reform is set to be introduced in 2027. There are some exceptions to this, particularly for patients subject to restriction orders. For example, a new s35 enables a tribunal or the Secretary of State to impose conditions on a detained, restricted patient who has mental capacity, upon discharge. Previously if such a patient had capacity, once discharged, conditions which amount to a Deprivation of Liberty could not be placed on such a patient and, where those were necessary, those patients were not discharged from their section. As of 18 February 2026, they can be discharged with such conditions as necessary.

Other sections of the Act which came into force on 18 February 2026 are:

• s30(2) (amendments relating to applications and references concerning discharged restricted patients)
• s32 (amendments relating to restricted patients subject to deprivation of liberty conditions)
• s35 (amendments relating to conditional discharge subject to deprivation of liberty conditions)
• s36(1) & (3)(b) (amendments relating to transfers of prisoners and others to hospital: conditions)
• s38 (amendments relating to transfer directions for persons detained in youth detention accommodation)
• s39 (minor amendment relating to patients subject to hospital and guardianship orders who are not subject to special restrictions).

These amendments largely focus on conditional discharge and transfers to hospital.

Comment 

The Mental Health Act 2025 seeks to reform the outdated 1983 Act by improving care for the most vulnerable and seriously ill patients in England and Wales. The reform is widely welcomed.

From a clinical perspective, it is unlikely the Act will have any immediate impact, save for those treating restricted patients, as above. However, its implementation will need to be closely monitored to ensure that patient care meets the expected standard in the years to come and that important community provision, particularly in relation to people with learning disabilities and autism is enhanced and improved to ensure they are cared for in more appropriate and therapeutic environments.