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Deprivation of Liberty and the Intersection between the Mental Health Act and Mental Capacity Act



Legal and social care professionals often grapple with the interplay between the Mental Health Act 1989 (MHA) and the Mental Capacity Act 2005 (MCA) when dealing with patients who are detained or deprived of their liberty.

This complexity has gained heightened significance with the evolving understanding of what constitutes a deprivation of liberty and recent judgments in the Supreme Court setting out the questions that should be asked when deciding which Act should be used to authorise a detention.

This article sets out the key differences between the Mental Health Act 1989 and Mental Capacity Act 2005, and explain when they should be used to authorise a deprivation of liberty.



The MHA enables the formal and informal admission of individuals with mental health issues for assessment and treatment, and covers decisions about medical treatment and detention in hospitals for mental disorders. The powers in the MHA are not based on capacity, which means the MHA can be used to detain someone who has capacity to object to their treatment or detention. The MHA can also be used to authorise the detention of people for assessment or treatment of a mental disorder who are considered a risk to others, not just themselves.


The MCA mandates acts or decisions on behalf of individuals lacking capacity to be made in their best interests and applies to most areas of decision-making. The Deprivation of Liberty Safeguards (DOLS) can be used if the person will be deprived of their liberty in a care home or hospital, but in other settings the Court of Protection has powers to authorise a deprivation.


The overlap between MHA and MCA is regulated by the provisions of Schedule 1A to the MCA. The core principle underpinning Schedule 1A is that someone who lacks capacity to consent to an admission to hospital for their mental health should be treated the same as someone who has capacity to consent to an admission in hospital for their mental health.

Deprivation of liberty – which Act should be used?

The MHA and MCA, in different situations, can be used to authorise how someone can be deprived of their liberty.

The general principle is that if the MHA can be used to deprive someone of their liberty, then the MHA should take precedence over the MCA. Charles J emphasised in GJ v The Foundation Trust [2009] EWHC 2972 (Fam) that you cannot “pick and choose” (at paragraph 45) between the MHA and MCA, stating that the MHA should have “primacy” if it can be used. The critical question, therefore, is whether the criteria for detention under the MHA is satisfied in that particular case.

The reason for the precedence of the MHA is that the MHA grants the adult and their family stronger rights and powers to object to their deprivation of liberty compared to the MCA. It is a statutory regime which a stronger set of safeguards underpinning the scheme. Under the MHA, Nearest Relatives can object to detention or discharge, with no equivalent concept under the MCA. Moreover, the MHA gives automatic powers of referrals to the mental health tribunal to appeal against their detention with automatic legal aid; objection to a deprivation of liberty under the MCA requires application to the Court of Protection. Finally, individuals detained under s3,37,45A, 47 or 48 MHA become eligible for free after-care under s117 once discharged, whereas under the MCA/DOLS, they remain subject to the means-tested regime of the Care Act 2014.

Under Schedule A1, a person who lacks capacity to consents to their deprivation of liberty is eligible for DOLS under the MCA unless:

  • They are detained under the MHA (Case A);
  • They are subject to MHA in the community such as s 17 leave or Conditional Discharge (Case B), Community Treatment Order (Case C), or guardianship (Case D), and DOLS detention would be incompatible with an MHA requirement;
  • They could be detained under MHA and are an objecting mental health patients (Case E).

Case A – the adult is already detained under MHA

When the adult has already been detained under the MHA, the use of MCA/DOLS is not necessary or appropriate.

If a patient is detained under MHA, and (a) they become subject to additional restrictions which amount rise to a deprivation of liberty (for example for the adult to be treated for a physical injury), and (b) they lack capacity to consent to those additional restrictions, the inherent jurisdiction will be required as set out in A NHS Trust v Dr A [2013] EWHC 2442 (COP)  and FS v RS and JS [2020] EWFC 63. The circumstances where this arises will be relatively narrow.

Case B – Section 17 leave

Patients detained under the MHA may leave the hospital only if granted leave of absence under s 17 by their responsible clinician, and conditions may be attached to the leave.

If the leave is granted under s 17(2), where it is granted either indefinitely or for a specific amount of time, and (a) the patient lacks capacity to make their own decisions about where to live, and their care and support; and (b) the patient’s residence, and care and support arrangements in the community would deprive the patient of their liberty, then DOLS or Court of Protection should be used because the MHA cannot authorise the detention outside of hospital.

If the leave is granted under s 17(2) and the patient has capacity to make their own decisions about where to live, and their care and support, they cannot be deprived of their liberty under DOLS, MCA or MHA. The inherent jurisdiction would be needed, and the circumstances in which the court would grant this would be narrow.

On the other hand, under s 17(3), a clinician can direct the patient to remain “in custody” of a person, which could potentially amount to a deprivation of liberty. Under s 17(3), the MHA can be used to authorise the patient’s deprivation of liberty outside hospital, whether they have capacity or not. This was originally looked at by the Supreme Court in 2018 in Secretary of State for Justice v MM [2019] AC 712, which prohibited the imposition of conditional discharge conditions amounting to detention or deprivation of liberty for restricted patients lacking capacity. Following this judgment, the Secretary of State issued guidance in 2019 which suggested to place patients with capacity who required a conditional discharge, with conditions amounting to a deprivation of liberty, on long-term escorted leave of absence under s 17(3). This was challenged in a recent High Court case, Cumbria, Northumberland Tyne and Wear NHS Foundation Trust v EG [2021] EWHC 2990 (Fam), where the Court examined the situation of placing a person with mental health problems, but capacity to make their own accommodation and care choices, in a community placement that involved depriving them of their liberty. The Court ultimately ruled that s 17 (3) may be used for such patients and established that a restricted patient could not be lawfully discharged into a placement that amounted to a deprivation of liberty.

In short, the MHA cannot deprive P of their liberty under s 17 leave, unless it is authorised by the responsible clinician using s 17(3) – this applies whether P has capacity, or not.

It should be further noted that it is also possible to use s 17 leave and DOLS/COP alongside each other, for example a trial placement in a care home or where leave is granted to another hospital for treatment of physical disorder.

Case B – Conditional discharge

For patients who lack capacity to consent to deprivation of liberty and their mental disorder poses a risk to themselves, a conditional discharge under MHA is possible into community arrangements which of themselves amount to a deprivation of liberty, with the deprivation of liberty authorised by DOLS/COP. A conditional discharge may arise either following the decision of the responsible clinician, or on application to the Tribunal for discharge, which may impose conditions including the power of recall where appropriate. Often a conditional discharge will only be granted following periods of leave so that the Tribunal or RC are satisfied that the discharge is safe.

However, if the conditions of a conditional discharge would deprive the person of their liberty, COP/DOLS should be used if the criteria are met. This is an obvious area of overlap between the two regimes as the Tribunal cannot discharge with conditions amounting to a deprivation, and the authorisation of the COP must first be obtained.

Case C – Community Treatment Orders

The Supreme Court has ruled that Community Treatment Orders (CTOs) cannot include conditions that lead to the deprivation of liberty under MHA.

The case in question, Welsh Ministers v PJ [2018] UKSC 66, involved an individual with borderline learning disability and autistic spectrum difficulties placed under a CTO with highly restrictive conditions. Overturning the Court of Appeal’s decision, the Supreme Court emphasised that the MHA cannot be used to impose conditions resulting in deprivation of liberty. If the conditions of a CTO amount to a deprivation of liberty, and the patient does not have capacity to consent to arrangements that give rise to a deprivation of liberty, the appropriate channel will be DOLS/COP.

Case D – Guardianship

Guardianship cannot authorise a deprivation of liberty, but it is possible to have a deprivation of liberty sitting alongside guardianship.

In the case of KD v A Borough Council [2015] UKUT 251 (AAC), Charles J provided a framework for determining the appropriateness of guardianship or DOLS. KD, diagnosed with Korsakoff Syndrome, had been under guardianship since 2012 and argued for discharge, asserting that DOLS was less restrictive. The Upper Tribunal declined to decide if KD was being deprived of liberty, but importantly expressed a view that a deprivation of liberty during guardianship should be authorised under the MCA (where applicable). The case also set out that standard authorisation under DOLS can provide for it to come into force at a time after the time at which it is given, and the COP can authorise any deprivation from a date in the future (para 43).

Case E – where the patient is deprived of their liberty within a hospital setting

If the patient has capacity to consent to the detention, they can be detained in hospital under the MHA as the MHA is not based on capacity.

If the patient does not have capacity to consent to the confinement, the recent case of Manchester University Hospital NHS Foundation Trust v JS & Others [2023] EWCOP 33 clarified the questions which need to be asked by professionals. In this case, Theis J addressed the complexities of Schedule 1A and upheld both the initial judgment from HHJ Burrows and endorsed the criteria set by Charles J in GJ v The Foundation Trust & Anor [2009] EWHC 2972 (Fam) for determining whether someone could be detained under the MHA. Theis J outlined a structured approach for practitioners and judges to address the key questions in the following order:

  • Firstly, is the patient a ‘mental health patient’? Practitioners must determine whether the real reason the patient is in hospital is for assessment or treatment of a mental disorder, in which case they are a mental health patient, or if the real reason they are in hospital is for assessment or treatment of a physical health condition, in which case they are not a mental health patient.
  • Secondly, is the patient an ‘objecting’ mental health patient? This will apply if they object to be admitted under the MHA. In determining whether or not the patient is objecting, regard must be had to all the circumstances (so far as they are reasonably ascertainable), including the patient’s behaviour, wishes and feelings, views, beliefs and values.
  • Finally, could the patient be detained under the MHA?
    • If they can, you cannot use the MCA to authorise the detention.
    • If the patient cannot be detained under the MHA, the MCA can be used.


In the evolving legal landscape, understanding the intricate interface between the MHA and MCA is imperative for legal and social care professionals. Staying informed, adapting strategies, and advocating for individuals’ rights within this interface ensure effective representation in this nuanced legal terrain.

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