Mental Capacity Act 2005: Capacity, Best Interests and Deprivation of Liberty
The Mental Capacity Act 2005 explained: the five principles, the two-stage capacity test, best-interests decisions and deprivation of liberty safeguards.
Quick answer
The Mental Capacity Act 2005 governs decisions for people in England and Wales who cannot decide for themselves. Its five principles: assume capacity unless the contrary is established; help the person decide before concluding they cannot; an unwise decision is not incapacity; act in their best interests; choose the least restrictive option. A person lacks capacity only if, at the material time, an impairment or disturbance of the mind or brain leaves them unable to understand, retain, or use and weigh the relevant information, or to communicate their decision. Best-interests decisions must weigh the person's past and present wishes, feelings, beliefs and values, and let them participate as fully as possible. Depriving someone of liberty requires a Court of Protection order or a Schedule A1 (DoLS) authorisation for hospital and care home residents. Where ongoing decisions are needed and there is no attorney, apply to the Court of Protection for a deputyship (£432 application fee, £266 if a hearing is needed).
Overview
The Mental Capacity Act 2005 (MCA) is the legal framework in England and Wales for making decisions on behalf of people who cannot make them for themselves. It is built on five statutory principles in s.1: a person must be assumed to have capacity unless it is established that they lack it; they must not be treated as unable to decide unless all practicable steps to help them have been taken without success; an unwise decision is not, by itself, evidence of incapacity; anything done for a person lacking capacity must be done in their best interests; and regard must be had to whether the purpose can be achieved in a way less restrictive of their rights and freedom of action. Capacity is decision-specific and time-specific: under s.2 a person lacks capacity only if, at the material time, they cannot make the particular decision because of an impairment of, or a disturbance in the functioning of, the mind or brain. The Act also strictly limits deprivation of liberty: s.4A says the Act does not authorise depriving anyone of their liberty except under a court order or a Schedule A1 (DoLS) authorisation for hospital and care home residents.
Who Can Use This Process
- You are caring for, or making decisions with or for, someone whose ability to decide is in doubt (dementia, brain injury, learning disability, mental illness, stroke, or temporary unconsciousness)
- You are a family member, attorney, deputy, or health or care professional needing to assess capacity for a specific decision
- You are planning ahead for someone or considering a Court of Protection deputyship because no attorney has been appointed
- The person is in England or Wales (Scotland and Northern Ireland have separate incapacity legislation)
Step-by-Step Process
Start from the presumption of capacity
Section 1 MCA requires that a person must be assumed to have capacity unless it is established that they lack capacity. The burden is on the person asserting incapacity, not on the individual to prove they can decide. Capacity questions only arise decision by decision — there is no such thing as being generally 'incapable' in law.
- Never infer incapacity from a diagnosis alone — a dementia or mental illness label does not itself establish anything
- Document why the question of capacity arose for this specific decision
Take all practicable steps to help the person decide
Under s.1(3), a person is not to be treated as unable to make a decision unless all practicable steps to help them do so have been taken without success. GOV.UK's guidance notes that mental capacity can come and go — for example with dementia and some mental illnesses — and that a person can also recover capacity, for example after a severe stroke. So choose the best time and setting, use simple language or visual aids, involve people the person trusts, and revisit the decision if capacity may return.
- Delay non-urgent decisions to a lucid time of day if capacity fluctuates
- Section 3(2) says a person understands if they can grasp an explanation given in a way appropriate to their circumstances — plain words, pictures or sign language
Apply the diagnostic limb of the two-stage test
Section 2(1): a person lacks capacity in relation to a matter if, at the material time, they are unable to make the decision for themselves because of an impairment of, or a disturbance in the functioning of, the mind or brain. Section 2(2) makes clear it does not matter whether the impairment or disturbance is permanent or temporary. Section 2(3) prohibits establishing lack of capacity merely by reference to a person's age or appearance, or a condition or behaviour that might lead others to make unjustified assumptions.
- Record the specific impairment or disturbance relied on and the evidence for it
- Intoxication, delirium and concussion can qualify as temporary disturbances — but the decision may simply need to wait
Apply the functional limb: the four abilities
Under s.3(1), a person is unable to make a decision if they cannot (a) understand the information relevant to the decision, (b) retain that information, (c) use or weigh that information as part of the process of making the decision, or (d) communicate the decision — whether by talking, using sign language or any other means. Failing any one limb because of the impairment means the person lacks capacity for that decision at that time.
- Retention only needs to last long enough to make the decision — short-term memory problems are not automatically decisive
- The 'use or weigh' limb is where most disputes arise; record how the person engaged (or could not engage) with the pros and cons
Never equate an unwise decision with incapacity
Section 1(4) states that a person is not to be treated as unable to make a decision merely because they make an unwise decision. GOV.UK repeats the point for lay decision-makers: you cannot decide someone lacks capacity because you think they have made a bad or strange choice. Capacity is about the process of deciding, not the outcome.
- A pattern of out-of-character, risky decisions can justify a proper capacity assessment — but the assessment must still apply the s.2/s.3 tests
If capacity is lacking, decide in the person's best interests
Section 4 governs best-interests decisions. The decision-maker must not decide merely on the basis of age, appearance or condition; must consider all relevant circumstances; must consider whether the person is likely to regain capacity and when; must, so far as reasonably practicable, permit and encourage the person to participate; and must consider the person's past and present wishes and feelings (especially any relevant written statement made when they had capacity), their beliefs and values, and the views of carers and anyone they named to be consulted. For life-sustaining treatment, the decision-maker must not be motivated by a desire to bring about death.
- Record the balance-sheet of factors — best-interests decisions are the most commonly challenged part of the MCA
- Choose the option that achieves the purpose in the way least restrictive of the person's rights and freedom of action (s.1(6))
Check who has legal authority — attorney, deputy or the Court of Protection
Day-to-day care decisions can often be made under the MCA's general defence, but significant property, financial or welfare decisions need formal authority: a registered Lasting Power of Attorney made while the person had capacity, or a deputy appointed by the Court of Protection if no LPA exists. Applying to become a deputy costs a £432 application fee, plus £266 if the court decides the case needs a hearing. Once appointed, deputies pay annual supervision fees — £320 for general supervision or £35 for minimal supervision (some property and affairs deputies managing less than £21,000) — and new deputies pay a £100 assessment fee.
- Fee remission or exemption may be available on low income — check the OPG deputy fees guidance before paying
- If the person still has capacity, making an LPA now is far cheaper and quicker than a deputyship later (see the lasting power of attorney guide)
Make sure any deprivation of liberty is authorised
Section 4A is emphatic: the Act does not authorise any person to deprive another of their liberty. There are only narrow gateways — giving effect to a Court of Protection welfare order under s.16(2)(a), or a deprivation authorised under Schedule A1 (the Deprivation of Liberty Safeguards) for hospital and care home residents. If a person who lacks capacity is under continuous supervision and control and not free to leave a care home or hospital, the arrangements must be authorised through DoLS (or a court order) — otherwise the detention is unlawful.
- Ask the care home or hospital who holds the DoLS authorisation and when it expires
- Family members can challenge an authorisation — the person has a right to a representative and to bring the matter before the Court of Protection
Costs
Important Warnings
Capacity is decision-specific and time-specific — a person may have capacity for one decision and lack it for another on the same day. Blanket 'lacks capacity' labels are unlawful.
You cannot establish incapacity from age, appearance, condition or behaviour that merely invites assumptions (s.2(3)), nor from a decision you consider unwise (s.1(4)).
Depriving a person of their liberty without a court order or Schedule A1 (DoLS) authorisation is unlawful — s.4A expressly withholds that power from carers, families and professionals alike.
Useful Links
Frequently asked questions
- What are the five principles of the Mental Capacity Act?
- Section 1 sets them out: (1) a person must be assumed to have capacity unless it is established that they lack it; (2) they are not to be treated as unable to decide unless all practicable steps to help them have been taken without success; (3) they are not to be treated as unable to decide merely because they make an unwise decision; (4) anything done for a person lacking capacity must be done in their best interests; (5) regard must be had to whether the purpose can be achieved in a way less restrictive of their rights and freedom of action.
- How is mental capacity assessed?
- By the two-stage test. Stage one (s.2): is there an impairment of, or disturbance in the functioning of, the mind or brain — permanent or temporary? Stage two (s.3): because of it, is the person unable to understand the information relevant to the decision, retain it, use or weigh it in making the decision, or communicate the decision by any means? The test is applied to the specific decision at the specific time; age, appearance and assumptions about a condition are expressly excluded as grounds.
- Can I decide someone lacks capacity because their decision seems foolish?
- No. Section 1(4) says a person is not to be treated as unable to make a decision merely because they make an unwise decision, and GOV.UK's guidance repeats that you cannot find incapacity because you think someone has made a bad or strange decision. What matters is whether the deciding process (understanding, retaining, weighing, communicating) is intact, not whether the outcome is sensible.
- Is lack of capacity permanent?
- Not necessarily. Section 2(2) states it does not matter whether the impairment or disturbance is permanent or temporary — but equally, GOV.UK notes that mental capacity can come and go (for example with dementia and some mental illnesses) and can be recovered (for example after a severe stroke). Decisions should be timed to the person's best functioning, and best-interests decision-makers must consider whether and when capacity is likely to return.
- What are the Deprivation of Liberty Safeguards (DoLS)?
- The MCA does not authorise anyone to deprive another person of liberty (s.4A). The exceptions are a Court of Protection welfare order under s.16(2)(a), or an authorisation under Schedule A1 — the Deprivation of Liberty Safeguards — covering hospital and care home residents. If someone lacking capacity is under continuous supervision and not free to leave, the arrangement must be authorised through one of those routes or it is unlawful detention.
- How much does a Court of Protection deputyship cost?
- The application fee is £432, plus £266 if the court decides the case needs a hearing. Deputies then pay annual supervision fees of £320 for general supervision, or £35 for minimal supervision (which applies to some property and affairs deputies managing less than £21,000), and new deputies pay a £100 assessment fee. Fee remission or exemption may be available on low income.