Preparing for Adulthood: Deputyship for Young People Who Lack Capacity

March 24, 2026

When a child who lacks mental capacity approaches their 18th birthday, families face an important legal shift. At 18, the law treats them as an adult who is presumed to have capacity under the Mental Capacity Act 2005. Parental responsibility no longer gives parents automatic authority to manage finances, consent to medical treatment, or make welfare decisions. If the young person cannot make specific decisions themselves, the Court of Protection may need to appoint a Deputy to act on their behalf.

Why Turning 18 Matters for Decision-Making

Before adulthood, parents and carers can make most decisions for a child. After 18, decisions about finances, care, and medical treatment must either be made by the young person or by someone with legal authority. Capacity is assessed decision by decision, meaning a young person may be able to make some choices but not others. Where they lack capacity for specific decisions, deputyship ensures that decisions can continue to be made safely and lawfully.

The Court of Protection’s Role

For young adults who cannot make decisions, the Court of Protection can:

  • Confirm that the young person lacks capacity
  • Appoint a Deputy to make financial or welfare decisions
  • Authorise certain decisions, such as managing money or arranging care
  • Approve a Statutory Will if needed

Applications can be prepared when the young person is 17 so that deputyship is in place soon after their 18th birthday.

Types of Deputyship for Young Adults
  • Property and Financial Affairs Deputyship: Managing bank accounts, benefits, savings, and property. Many young adults with disabilities receive significant financial support, including benefits or personal injury settlements. A Deputy ensures these funds are managed responsibly and in the young person’s best interests.
  • Personal Welfare Deputyship: Making decisions about care, living arrangements, and medical treatment. These are rare and granted only where ongoing, complex decisions are needed.
When Families Should Consider Deputyship

If deputyship is not in place when a young person who lacks capacity turns 18, parents and carers can suddenly find themselves unable to make even the most routine decisions on their behalf. Banks, healthcare providers, schools, colleges, social services and care agencies are required to treat the young person as an adult, meaning they may refuse to discuss finances, share information, or act on instructions without proper authority.

This can delay access to benefits, disrupt care arrangements, and create difficulties in managing money, paying bills, or consenting to medical treatment. In some cases, essential decisions such as arranging specialist care or managing compensation funds cannot be

made at all until the Court of Protection appoints a Deputy, leaving families in a vulnerable and stressful position during an already significant transition.

However, deputyship is not always required. We help families understand whether deputyship is necessary or whether a less formal arrangement would meet their needs.

How Our Firm Supports Families

The transition to adulthood can feel overwhelming for families caring for a young person who lacks capacity. We help families prepare for this transition by guiding them through capacity assessments, deputyship applications, and the responsibilities that follow. Our team ensures that parents and carers have the legal authority they need to continue supporting their child into adulthood, with clear advice tailored to the young person’s needs. If your child is approaching 18 and you are unsure what legal steps are required, contact us to speak to a member of our Private Wealth and Inheritance Team.

Graeme Black
Partner, Private Wealth & Inheritance
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This reflects the law and market position at the date of publication and is written as a general guide. It does not contain definitive legal advice, which should be sought in relation to a specific matter.

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