Major shift in mental capacity law as the Supreme Court overrules Cheshire West judgment regarding deprivations of liberty and valid consent

On 2 June 2026, the Supreme Court handed down a long-awaited judgment on deprivations of liberty, mental capacity and valid consent, departing from its own 2014 ruling in Cheshire West. The case follows a reference by the Attorney General for Northern Ireland (the appellant) of a devolution issue under paragraph 34 of Schedule 10 to the Northern Ireland Act 1998.

In this judgment, the Supreme Court reconsidered the legal framework used to determine when a person is deprived of their liberty under Article 5 of the European Convention on Human Rights. The Court ultimately concluded that the approach adopted in P v Cheshire West and Chester Council [2014] UKSC 19 had become overly rigid and did not accurately reflect the requirements of Article 5. As a result, the "acid test" established in that case is now no longer the governing test for identifying a deprivation of liberty.

By way of reminder, the Supreme Court had originally held in Cheshire West that the “acid test” for a deprivation of liberty is whether an individual is subject to “continuous supervision and control” and “not free to leave.”

The conventional interpretation of the 2014 decision has been that, where a person lacks the mental capacity to decide where they should live and their living arrangements meet the “acid test” — namely, that they are subject to continuous supervision and control and are not free to leave — they will be regarded as deprived of their liberty for the purposes of Article 5.

The Court rejected the idea that deprivation of liberty can be determined primarily by asking whether a person is under continuous supervision and control and not free to leave. Instead, it held that the question requires a broader assessment of the individual's circumstances. No single factor is determinative. The task is to evaluate the overall nature and effect of the arrangements in place and to decide whether they amount to a deprivation of liberty when viewed in their full context. 

In carrying out that assessment, a range of considerations may be relevant. These include the degree of control exercised over the person, the extent to which their movements are restricted, the opportunities available to maintain relationships and participate in ordinary activities, the duration of the arrangements, their purpose and necessity, and whether less restrictive alternatives exist. The Court also emphasised that the individual's own experience of the arrangements should not be ignored. Their wishes, feelings, level of contentment, and any signs of objection may all assist in understanding the true nature of the restrictions imposed.

The court focused on 6 key factors in its ruling.

1. The “acid test” is not enough on its own to prove deprivation of liberty; courts must assess the person’s full situation, including the type, duration, effect and implementation of the restrictions. 
2. Compliance or lack of objection can be legally relevant, especially where the person can show, even tacitly, that they are content with their living arrangements. 
3. Article 5 protects physical liberty, not every restriction on movement, so the care setting matters; living at home or in supported accommodation is different from detention in prison or hospital. 
4. A person’s own physical or mental limitations must be considered, rather than treating all resulting restrictions as state-imposed deprivation of liberty. 
5. The purpose of the restrictions may be relevant, particularly where measures are imposed for care, support or protection. 
6. Lack of mental capacity does not automatically mean lack of valid consent; a person may still be able to express whether they are happy or unhappy with their arrangements. 

A central aspect of the judgment concerns the role of consent. The Court held that a person who lacks capacity to make a particular decision about residence or care may nevertheless be capable of giving valid, subjective consent to the arrangements in which they are living. This means that the absence of decision-making capacity under the Mental Capacity Act does not automatically lead to the conclusion that a person's compliance is legally irrelevant. Where a person genuinely accepts and agrees to their living arrangements, that fact may be highly significant when considering whether Article 5 is engaged.

The Court further stressed that capacity is decision-specific and that the law should recognise the distinction between being unable to make a formal legal decision and being able to understand and accept one's day-to-day circumstances. Accordingly, the views and experiences of the individual must form part of the overall analysis rather than being excluded from it.

This decision marks a substantial shift in the law. It moves away from a standardised test that often produced the same result regardless of the person's actual experience, and replaces it with a more nuanced evaluation focused on the reality of the individual's situation. Practitioners, public bodies and courts will now need to undertake a more detailed examination of the particular facts of each case when determining whether arrangements amount to a deprivation of liberty requiring Article 5 safeguards. 

A Reference by the Attorney General for Northern Ireland under paragraph 34 of Schedule 10 to the Northern Ireland Act 1998 judgment

A Reference by the Attorney General for Northern Ireland under paragraph 34 of Schedule 10 to the Northern Ireland Act 1998 press releases

3rd Jun 2026

Carolina Bax

Call 2023