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Mental Capacity Act 2005

The Mental Capacity Act 2005 provides a statutory framework for people who may lack capacity to make decisions for themselves. 


Section 1 of the Mental Capacity Act sets out the 5 ‘statutory principles’ – the values that underpin the legal requirements in the Act. The Act is intended to be enabling and supportive of people who lack capacity, not restricting or controlling of their lives. It aims to protect people who lack capacity to make particular decisions, but also to maximise their ability to make decisions, or to participate in decision-making, as far as they are able to do so.

The 5 statutory principles are:

  1. A person must be assumed to have capacity unless it is established that they lack capacity.
  2. A person is not to be treated as unable to make a decision unless all practicable steps to help them to do so have been taken without success.
  3. A person is not to be treated as unable to make a decision merely because they make an unwise decision.
  4. An act done, or decision made, under this Act for or on behalf of a person who lacks capacity must be done, or made, in their best interests.
  5. Before the act is done, or the decision is made, regard must be had to whether the purpose for which it is needed can be as effectively achieved in a way that is less restrictive of the person’s rights and freedom of action.

The MCA Code of Practice provides clear guidance about how the Mental Capacity should be put into practice.

Mental capacity should usually be assessed by the person (a family member or professional) who would be responsible for that decision if that person were found to lack capacity. When assessing capacity, certainty is not required. The law requires a reasonable belief that, on the balance of probabilities, the person has, or has not, got capacity for that specific decision.

The Court of Protection

The Court of Protection oversees the operation of the Mental Capacity Act and can deal with issues, including financial and serious healthcare matters, concerning people who lack the mental capacity to make their own decisions. It can resolve disputes, such as when the person's family and the professionals involved disagree about what is in the person's best interests.

Office of the Public Guardian

The Office of the Public Guardian helps protect people who lack mental capacity to make decisions for themselves. It registers Lasting Powers of Attorney and supervises Court-Appointed Deputies. It provides evidence to the Court of Protection and guidance to the public. The Office of the Public Guardian works with a range of agencies, such as the police and adult care services to help ensure the Mental Capacity Act is followed.

The Independent Mental Capacity Advocate Service (IMCA)

Independent Mental Capacity Advocates (IMCAs) must be independent from the allocated workers that support people. IMCAs help uphold people’s rights and the wishes of people who lack the capacity to make decisions about serious medical treatment and changes of accommodation. They may be allocated if, at the time such decisions need to be made, the person has no-one else (other than paid staff) to support or represent them or be consulted.