Mental capacity and the law in England and Wales

The Mental Capacity Act 2005 aims to protect people who cannot make a decision for themselves.

The Mental Capacity Act 2005

The Mental Capacity Act 2005 came into force in 2007. It applies to people aged 16 and over in England and Wales.

The Act aims to protect people who are not able to make a decision for themselves. It means a person can plan ahead, in case they are ever in that situation in the future. It explains:

  • who can make decisions for them
  • in which situations they can make decisions
  • the process to follow when making decisions.

There are many parts to the Act, including information on lasting power of attorney and advance decisions to refuse treatment.

The Act states that a person lacks capacity if they are unable to make a decision for themselves about a specific matter. This may be because of an impairment of, or a disturbance in, the functioning of the mind or brain.

A person lacks capacity if they cannot do one of the following:

  • understand information about the decision
  • remember the information
  • use or consider the information as part of the decision-making process
  • communicate their decision by talking, using sign language or any other means.

Managing your care if you have not planned ahead

Best interests decisions

Usually, your carers and family are involved in making everyday decisions about your care. However, sometimes a decision may need to be made about your medical care or treatment.

In this case, a senior healthcare professional makes the decision. They base this decision on their experience and what they know about your situation. They will discuss the decision with your family, friends and anyone else involved in your care. These decisions are called best interests decisions.

The Mental Capacity Act 2005 lists factors that need to be considered when someone is making a best interests decision. These include considering:

  • all the relevant circumstances
  • your past and present wishes
  • your values and beliefs
  • the views of people caring for you, such as a family member, friend or carer.

A best interests decision must not be based on your age, condition, appearance or any aspect of your behaviour. This is stated in the Mental Capacity Act. The Act also ensures that those who make decisions think about all the relevant circumstances about your care. It also makes sure that the motives of the person making the decision are correct and in your best interests.

Decisions made by healthcare professionals

If a best interests decision is about life-sustaining treatment, a health professional cannot be motivated by a desire to bring about someone’s death. They should look at the appropriate treatment options available to make sure that the best interests of a person are met.

The views of family members and friends are considered in a best interests decision. But the person making the decision has the final responsibility. This is usually a senior healthcare professional. Sometimes this means that what the family wants is not what happens. In this situation, the healthcare professional should explain the law regarding best interest decisions and their reasons for the decision.

Independent Mental Capacity Advocates

In some situations, medical staff may need to appoint someone as an Independent Mental Capacity Advocate (IMCA). This person acts as your advocate and represents your interests, if you cannot do so yourself. This usually only happens if you do not have:

IMCAs are usually appointed if you need a non-urgent decision on your behalf about serious medical treatment, such as:

  • giving a new treatment
  • stopping treatment that has already started
  • withholding treatment that could be offered.

In this situation, the IMCA considers how these actions will affect you. They think about whether your life is likely to be made better or worse. For example, a new treatment may cause side effects such as sickness and pain, but only give you a few more weeks to live. The IMCA works with your medical team to make sure that your civil, human and welfare rights are respected. They consider all the options before making a decision.

IMCAs may also be appointed if an NHS body or local authority suggests a change of accommodation that means you will:

  • stay in hospital for longer than 28 days
  • stay in the care home for more than 8 weeks.

IMCAs may also be appointed to help make decisions in relation to care reviews and adult protection cases. You can find out more information about the IMCA service from