AGNI Supreme Court decision

Written by Sibs trustee and solicitor Carol McBride:

Explaining the AGNI Supreme Court decision (2026) and what it means for siblings

“In June 2026, the UK Supreme Court handed down an important ruling which fundamentally changes when a disabled person is considered to be “deprived of their liberty” in care settings. The case is commonly referred to as AGNI (as it was brought by the Attorney General for Northern Ireland).

For over a decade, the law had followed an earlier case called Cheshire West which said that a person was deprived of their liberty if their care arrangements entailed continuous supervision, they were not free to leave and there was an element of state involvement —regardless of whether they seemed happy or settled. This meant that many people with disabilities in care homes, hospitals, or supported living were automatically treated as deprived of their liberty and were given legal safeguards (such as formal authorisation, rights to independent review and a route to challenge their care arrangements in the courts).

The AGNI decision has changed this approach in two key ways:

• First, the Supreme Court rejected the old “acid test” referred to in Cheshire West and said that deprivation of liberty must now be assessed using a broader, multi-factor approach. This means looking at the person’s whole situation—such as the type of restrictions, how long they last, and their impact—rather than applying a simple rule.
• Secondly, the Court said that a person can sometimes be treated as consenting to their care arrangements even if they lack formal mental capacity, if their wishes and feelings show they are content.

What this means for people with a disabled brother or sister

For families, this is a very significant shift. Previously, if your brother or sister lacked capacity and was under close supervision, the law would almost always treat them as deprived of their liberty. That triggered safeguards—regular reviews, rights to challenge their placement, and access to advocacy.

Now, some people in exactly the same situations may no longer legally count as deprived of their liberty, especially if they appear settled or do not object.

This can have mixed consequences:

• On one hand, it may mean less bureaucracy and fewer formal legal processes where the person is genuinely happy and well cared for.
• On the other hand, it means fewer automatic safeguards. Some individuals who would previously have had independent oversight of their care may no longer receive those protections. This can also affect their eligibility to legal aid and legal representation.

Why it matters

The law is now less clear-cut and more dependent on interpretation. Whether someone is deprived of their liberty will depend on a detailed, case-by-case assessment rather than a simple test, and it is likely that further case law will follow. Because there was no individual at the heart of the Attorney General’s application to the Supreme Court, there is no route of appeal to the European Court of Human Rights. There is also no ‘grace period’ so professionals are being expected to apply the new test immediately. While the Department of Health and Social Care has offered interim guidance [UK Supreme Court 2026 judgment on what constitutes a deprivation of liberty – GOV.UK] it is likely to take some time for practitioners and families to work through the implications of the ruling.

For siblings, the key impact is that the responsibility may shift more towards families and professionals to actively check that care arrangements are appropriate and sufficiently person-centred.”

More support for siblings

It can be extremely difficult for siblings when a change like this happens. Siblings worry about how they will be impacted, what the future will hold and what it means for the safety of their disabled or neurodivergent brother or sister. If this is you, please know that you are not alone and you deserve support.

Here are some options:

• First and foremost, look after yourself. Read our advice on coping with worry, see your GP if you’re struggling with anxiety and keep prioritising your own self-care wherever you can (like sleep, eating well, exercising, doing things you enjoy).
• Connect with other siblings on our private Facebook community #Siblife and at an adult sibling support group to meet others who share your feelings and experiences.
• Get more information as it can make you feel more empowered. Learn more about mental capacity from our guide on decision-making. If you’re concerned about abuse or neglect, read our advice on taking actions on safeguarding concerns. If you’re not sure how to speak up about care that doesn’t meet your brother or sister’s needs, take a look at our guide on how to make a complaint.