The Mental Health Bill

The Mental Health Bill (‘the Bill’) is currently making its way through Parliament. It has been scrutinised by the Public Bill Committee and is now in its final stage of consideration of amendments before Royal Assent (October 2025).

As part of our series of articles addressing different sector perspectives, we highlight here how the proposed changes to detention criteria will impact acute and mental health providers across the UK.

What are the main changes to detention criteria?

There are a number of changes in proposal which will significantly impact all healthcare providers in the UK.

Firstly, the change in threshold for detention under the MHA 1983 (‘the Act’) for those being detained under Part 2 of the Act, the ‘civil sections’ as they are often referred to.

Clause 5 of the Bill amends the criteria for detention under section 2, 3 and 5 of the Act and the criteria for renewal of detention under section 20. It makes provision as to the level of risk that a patient must pose to be detained. This will change the detention criteria to ensure that people can only be detained under these sections if they pose a risk of serious harm either to themselves or to others. This change is to support the principle of least restriction, to minimise restrictions on liberty so far as it is consistent with ensuring patient wellbeing and safety, and public safety.

The explanatory notes to the Bill confirm that the purpose of these changes is to provide greater clarity as to the level of risk of harm that a person must present to be detained. Firstly, the “serious harm” test sets out the severity of the harm a patient must pose to fulfil the criteria for detention under section 2 or 3. The Bill does not define serious harm, further guidance will be provided in the Code of Practice. Secondly, the “nature, degree and likelihood” test introduces a new requirement that the clinician must consider the likelihood that this harm will occur, when deciding to admit the individual under section 2 or 3.

The serious harm element will also now apply to section 5(4) nurses holding powers. It will also apply to renewals of detention – as will the likelihood test of this occurring, for Part 2 patients and also Part 3 unrestricted patients such as those on s.37 hospital orders without restriction.

These changes will also apply in relation to the making of community treatment orders (CTOs) and also impact the thresholds for discharge by the Tribunal as the grounds for discharge will be aligned to the detention criteria, with broader change in that area for Part 3 patients too.

Secondly there is a change to the definition of appropriate treatment.

Consideration must be given to whether there is a reasonable prospect that the outcome of the treatment would have a therapeutic benefit for that patient, and the test for appropriate treatment is brought forward in the Act from where it was in s.145 to be on the face of the detaining criteria as a new section 1A

Thirdly, detention for treatment under Section 3 of the Act will no longer be possible for autistic people or those with a learning disability unless they also have a co-occurring psychiatric disorder.

What impact may LD and/or ASD related changes have?

These amendments have the effect of removing, for the purposes of Part 2 of the Act, people with a learning disability and autistic people from the scope of the conditions for which a person can be detained for compulsory treatment under section 3. People with a learning disability and autistic people will only be able to be detained for treatment under Part 2 of the Act if they satisfy the conditions set out in section 3 of the Act, which includes that they have a co-occurring psychiatric disorder which is not learning disability or autism (LD and/or ASD).

The proposed changes also mean that it will no longer be possible to place a person with a learning disability or an autistic person on a CTO unless they have a co-occurring psychiatric disorder that meets the criteria.

Section 2 periods of assessment may still include people with LD and/or ASD - this period could be used to assess for any co-occurring mental health condition.

Part 3 of the MHA is to be unchanged however in relation to LD and/or ASD and a person could be detained under Part 3 of the Act with no co-occurring mental disorder exists if the other criteria are met.

How will these changes impact providers and commissioners?

In relation to LD and/or ASD, we still have lots of people detained in hospital who do not have co-occurring psychiatric disorders who are awaiting discharge under the Building the Right Support programme, often still referred to as Transforming Care. There is a concern that community-based homes are still not available for those awaiting discharge, and that if those already in the community have a crisis in which they need to move from their accommodation, that there are limited crisis options currently other than hospital. Hospital is rarely a good or long-term solution to manage these crisis situations, but providers of care and commissioners will need to consider robust contingency planning.

In addition, in relation to the wider detention criteria changes, the higher threshold for detention means community mental health services and social care services will need to be able to manage people more effectively in the community and consider how those who may be presenting as acutely unwell but who may not meet the serious harm threshold can be supported effectively.

It is also quite possible that more people will end up presenting in A&E in relation to these changes and there are already grave concerns about how people with mental health issues can be effectively managed and assessed outside of designated health based places of safety and the legal frameworks for holding people where assessed as meeting criteria currently where there is no bed for example. We anticipate those concerns for staff on the ground will increase with higher thresholds for detention being considered, and how other duties of care to patients can be met when unable to detain under the MHA.

Tips for providers and commissioners to manage this

1. Providers and commissioners need to consider the training needs within their local area.

2. We know that certain professional organisations have some concerns about the changes to detention criteria and how practitioners will establish serious harm on assessments for initial detention where there may be limited information, and/or on how to determine what the ‘likelihood’ of that serious harm occurring is. There is some scope to consider this in the context of dangerousness criteria currently which mental health professionals are familiar with relating to nearest relative applications for discharge, and barring of those applications as they present a similar test to that which is now relevant for initial detention. This is something which will be further considered in the new Code of Practice. The impact on detention numbers will need to be monitored to see how trends develop over time post implementation and medical scrutiny post admission will remain an important part of detention.

3. Service delivery generally should take into consideration the issues we have noted regarding increased community provision, both for those with acute mental health conditions and for those with LD and/or ASD, and good partner agency relations will be required to ensure joined up approaches. This is difficult in what is a changing, complex commissioning landscape but cannot be avoided in terms of future planning.

If your organisation requires advice or training in relation to the Mental Health Bill and/or associated matters, please do not hesitate to get in touch with our experienced team.

This article was co-authored by Rachael Watkinson.