What is deputyship for a young adult who lacks capacity?

Deputyship is a Court of Protection appointment that lets you make decisions for a young adult (16+) who can't make them themselves: it covers either finances (common) or health and welfare (rarely granted). The court appoints you under the Mental Capacity Act 2005 (section 16) once your child has been assessed as unable to make a particular decision. It is not about a diagnosis. The test is whether they can make the specific decision, assessed under the Act, so deputyship can apply whatever the condition.

Why this comes up at 16 and 18

The Mental Capacity Act presumes that a person can make their own decisions from age 16. Your legal parental responsibility ends when your child turns 18. From that point you have no automatic right to manage an adult child's bank account, benefits, tenancy or medical care, even if you have always done so. As the charity Contact explains for families approaching adulthood, this is the cliff edge many parents only notice when a bank or the DWP suddenly stops talking to them.

The two types of deputy

GOV.UK sets out two kinds of deputy:

• Property and financial affairs: managing money, benefits, savings and assets. This is the common route, usually needed to deal with bank accounts and benefits once your child is 18.
• Personal welfare: decisions about care and medical treatment. The court grants these rarely, and you cannot be a welfare deputy for someone under 16.

Either way, a deputy is supervised by the Office of the Public Guardian and has to send it a report every year.

You may not need it at all

This is the qualifier most pages leave out. The court has to prefer a single one-off decision to handing someone ongoing control, and a deputy's powers must be as limited as is reasonably practical (section 16(4)). Welfare deputyships are rare for exactly this reason. On top of that, day-to-day decisions about care, routine treatment and everyday money can usually be made in your child's best interests without any court order, under section 5 of the Act. Many families of a young adult with lifelong needs find they do not need deputyship for those. Where it is most often genuinely needed is property and financial affairs, to unlock bank accounts and benefits. Unlike a Lasting Power of Attorney, deputyship can be set up after capacity is already lost, which is why it is the route families of young people with lifelong conditions tend to use.

For the decisions you can and can't still make, see whether you still make decisions after they turn 18 and what a mental capacity assessment at 16 involves.

What it costs in 2026

The application fee is £421, with a £100 assessment fee for new deputies and a further £259 if the court holds a hearing. Annual supervision is then £320, or £35 for a property-and-affairs deputy managing under £21,000. Fee reductions and exemptions are available on a low income, and you can check the current figures on the GOV.UK fees page before you apply.

This page is general information, not clinical or legal advice.