Mental Capacity Act 2005

The Mental Capacity Act 2005 is the governing statute in England and Wales for decisions made on behalf of adults who lack the mental capacity to make those decisions themselves. It came into force on 1 October 2007 and provides the legal framework for Lasting Powers of Attorney, advance decisions to refuse treatment, the Court of Protection, and the rules for assessing capacity and making "best interests" decisions. [source: legislation-gov-uk/mental-capacity-act-2005-2026-05-02.html]

Five statutory principles sit at the heart of the Act (section 1):

1. A person is presumed to have capacity unless it is established otherwise.
2. A person is not to be treated as unable to make a decision unless all practicable steps to help them have been taken without success.
3. A person is not to be treated as unable to make a decision merely because the decision is unwise.
4. Anything done for, or on behalf of, a person who lacks capacity must be done in their best interests.
5. Before doing the act, regard must be had to whether the purpose can be effectively achieved in a way less restrictive of the person's rights and freedom of action.

The capacity test (section 2): a person lacks capacity in relation to a matter if, at the material time, they are unable to make the decision because of an impairment of, or a disturbance in the functioning of, the mind or brain. Section 3 sets out four limbs for inability: unable to understand the relevant information, retain it, use or weigh it as part of the decision-making process, or communicate the decision.

Lasting Powers of Attorney are introduced by sections 9–14 and Schedule 1; advance decisions to refuse treatment by sections 24–26; the Court of Protection by sections 45–63.

Northern Ireland equivalent: the Mental Capacity Act (Northern Ireland) 2016 is the corresponding statute, but as of 2026 it is only partially commenced — significant provisions are not yet in force. Scotland's equivalent regime is the Adults with Incapacity (Scotland) Act 2000, which uses different terminology (continuing power of attorney, welfare power of attorney, intervention orders, guardianship orders) and a different supervisory structure (the Office of the Public Guardian for Scotland).

→ Lasting power of attorney · Advance decisions and living wills

AfterLoss

See how AfterLoss handles planning mode for where decisions made under the Act (advance decisions, lasting powers of attorney) sit alongside the rest of someone's planning record.

Last verified: 2 May 2026 against legislation.gov.uk Mental Capacity Act 2005.