The Mental Health Bill represents the most significant reform to mental health law in England and Wales since 1983. Rather than replacing the Mental Health Act entirely, it introduces targeted amendments that fundamentally reshape when and how people can be detained, strengthens patient autonomy, and addresses long-standing inequalities. With Royal Assent now granted, the Bill will be implemented in phases over several years.
The Bill has three core purposes: ensuring detention is used only when necessary and genuinely therapeutic; giving people greater control over their care; and tackling persistent inequalities, including racial disparities in detention rates and inappropriate long-term hospitalisation of people with learning disabilities or autism.
The five most significant reforms
Five reforms stand out for their system-wide impact.
- Stricter criteria for detention under Section 3, requiring evidence of serious harm, therapeutic benefit, and genuine necessity.
- Learning disability and autism are excluded as grounds for treatment detention.
- A nominated person model replaces the nearest relative scheme.
- Advance Choice Documents become statutory, requiring services to consider patient preferences documented before a crisis
- Increased frequency of tribunal reviews with higher expectations around documentation and transparency.
These changes are interconnected. The higher detention threshold demands more structured clinical reasoning captured in improved documentation. The autonomy reforms require new systems for involving patients. Together, these reforms represent a recalibration of the entire Mental Health Act framework.
Understanding the new detention criteria
The revised detention criteria under Section 3 mark the most fundamental shift. Currently, detention requires a mental disorder warranting detention, necessity for health or safety or to protect others, and appropriate treatment availability. The new test is considerably more demanding: detention now requires a psychiatric disorder, risk of serious harm to self or others, evidence that treatment cannot be provided without detention, and demonstration that treatment will deliver therapeutic benefit.
Clinicians and AMHPs must explicitly demonstrate that risk reaches the serious harm threshold, detention is the only viable option, and treatment has clear therapeutic purpose. Assessments must explore risk dynamics thoroughly, explicitly consider community alternatives, and articulate how interventions will reduce risks. Applications will require substantially more detailed reasoning about why detention is unavoidable. Tribunals will expect each element addressed explicitly.
Learning disability and autism
The exclusion of learning disability and autism as grounds for Section 3 detention is ethically significant but operationally complex. However, immediate impact may be modest. Relatively few people are detained solely on this basis without co-existing psychiatric conditions.
Three displacement routes require planning. Individuals lacking capacity may be held under Mental Capacity Act frameworks offering fewer protections. People developing psychiatric conditions remain detainable. Behaviours from unmet needs may escalate into criminal justice pathways.
Success depends entirely on community capacity. Without stable accommodation, autism-specific services, and intensive support teams, individuals may cycle through longer Section 2 admissions or crisis pathways. The learning disability and autism exclusion will only take effect once adequate community alternatives exist.
Autonomy reforms
The nominated person model allows individuals to choose who represents them during detention. Where capacity is lacking, an AMHP appoints the most appropriate person. The nominated person receives information about detention, treatment, and discharge decisions. Advance Choice Documents record treatment preferences, care preferences, and relational preferences created before a crisis. ICBs and Local Health Boards must make appropriate arrangements for supporting ACD creation, storage, and accessibility. Clinicians must have regard to ACDs when making treatment decisions and record reasons when departing from them.
Early pilots showed improved rapport and fewer conflicts, though challenges around staff time and digital accessibility remain. These reforms require cultural change, demanding supportive systems, adequate time, and digital infrastructure.
Oversight and documentation
Renewal periods for Section 3 detention reduce from six months to three months initially, meaning more frequent tribunal reviews. Tribunals gain expanded powers to make recommendations. Care and treatment plans become statutory requirements. Second Opinion Appointed Doctor processes are updated, with approval required more quickly in certain circumstances.
The Bill introduces detention criteria checklists requiring clinicians to record how the serious harm threshold is met, why detention is necessary, what therapeutic benefit is expected, and how treatment aligns with ACDs and nominated person views.
Digital systems become increasingly important. Paper-based processes make it difficult to locate ACDs during crises, verify nominated person appointments, or track tribunal deadlines. Trusts investing early in digital Mental Health Act systems will be better positioned.
Section 117 aftercare and police powers
The Bill clarifies Section 117 aftercare responsibilities, ensuring the authority placing someone out of area remains responsible for their aftercare needs. This removes a major source of dispute between local authorities and ICBs.
The Bill removes police stations from the statutory list of places of safety for adults. However, many regions still face shortages in health-based places of safety. Police forces, mental health trusts, and ambulance services must strengthen crisis pathways and ensure efficient handovers.
Implementation and leadership priorities
Implementation will be phased over multiple years. Early provisions include updated legal wording and documentation duties. Medium-term reforms include tribunal changes and ACD infrastructure duties. Long-term reforms include the learning disability and autism exclusion and digital system upgrades.
Leaders must prepare now. Trust boards should establish governance for readiness, invest in digital foundations, and prepare staff. AMHPs must build confidence in applying new criteria. ICBs and local authorities should build ACD infrastructure and strengthen community capacity. Police forces must update operational guidance.
Key risks and opportunities
Three major risks require attention: learning disability and autism reforms depend on community capacity; increased legal scrutiny will strain services; and digital readiness gaps exist across organisations.
However, these challenges represent opportunities to modernise mental health care, reduce unnecessary detention, improve patient experience, support shared decision-making, and embed therapeutic purpose at the Act’s heart.
Conclusion
The Mental Health Bill recalibrates mental health law for modern expectations of rights, accountability, and personalised care. Leaders should explore: understanding interpretive demands of new detention criteria; planning realistic implementation timelines; building community capacity before commencement; investing in digital infrastructure; and developing workforce capacity.
The Bill provides the framework for a mental health system that reflects what people value most: care that is safe, respectful, personalised, and grounded in their own voice. Success will come through policy, staffing, culture, digital tools, and partnership working that translate the Bill’s intentions into daily reality.
