Know your rights under the Mental Capacity Act 2005


The Mental Capacity Act 2005 (MCA 2005) came into effect in 2007. The purpose of this Act is to offer protection to those who lack mental capacity (defined below). This article will explain how mental capacity is defined under the Act, the role of mental capacity assessments, your options if deemed incapacitated and the procedure for disputing a capacity assessment outcome.

What is mental capacity?

The Act defines mental capacity as a person’s ability to make decisions for themselves. As a form of guidance, the MCA 2005 listed four criteria when determining capacity during a mental capacity assessment. If:

  1. you do not understand the information provided about the decision or what making the decision means,
  2. you cannot retain information needed to make the decision,
  3. you cannot process the information needed to make the decision or weigh up the positives and negatives,
  4. you cannot communicate their decision,

then it is likely that you will be deemed as lacking capacity. Communication does not need to be through words but could be through signs or other non-verbal cues and taking a long time to communicate does not matter – the Act emphasises the need to consider individual circumstances.

Mental incapacity can arise any time and unexpectedly, for example from a sudden accident, stroke, dementia, severe learning disability or severe mental health problem; and can be temporary or permanent depending on the individual’s medical circumstances. A person who lacks capacity is excluded in law to perform certain things, for example: make a valid will, sign important legal documents and consent/refuse medical treatment.

The role of mental capacity assessments

When assessing mental capacity, the starting point is to always assume you have the mental capacity to make decisions for yourself, unless established otherwise. The person who may lack capacity must also be supported to make as many decisions as they can for themselves.

A mental capacity assessment involves a relevant person carefully following the five main principles of the MCA 2005 and the Code of Practice to determine whether the adult who may lack capacity can make decisions themselves.

These five principles are:

  1. Until proven otherwise, it should be presumed that all individuals have capacity.
  2. A person is not to be treated as being unable to make a decision unless all practicable steps have been taken to help him make that decision themselves.
  3. A person is not to be treated as being unable to make a decision merely because they make an unwise decision.
  4. Any decision made or act done under the MCA on behalf of a person who lacks capacity must always be in their best interests.
  5. Before the decision is made, or the act is done, there must be due consideration as to whether the purpose for the decision or act can be achieved as effectively in a way that is less restrictive of the person’s rights and freedom of action.

Although the Act states that health or social services professionals or solicitors can conduct formal assessments, in reality, it is carers and family members who usually conduct informal assessments on a day-to-day basis. These principles should be strictly adhered to by those conducting the assessments as they are integral to protecting the rights of the person who may lack capacity. Until the assessment shows the person lacks capacity, this person retains their right to make decisions for themselves.

Per the Act, the purpose of carrying out a mental capacity assessment is to answer two crucial questions:

  1. Does the affected person have an impairment or disturbance of brain function? The MCA stated that this can include brain illnesses, injuries such as concussion, mental illness, or drug and alcohol use
  2. Does the impairment or disturbance inhibit the affected person from making a specific decision when they need to make it, and no support can help them make the decision?

The Code of Practice is comprehension guidance on how to undertake a mental capacity assessment and what to consider when making decisions. More information can be found here:

Making decisions when lacking capacity

If you are deemed to lack capacity, you cannot consent to or refuse medical treatments. This means someone else will have to make these decisions on your behalf. This person must make decisions that are in your best interest – and in doing so, must perform what is known as the ‘best interests test’. This person can be formally elected by yourself in advance while you still have the capacity (known as a Lasting Power of Attorney) or by your medical/healthcare professional, and you can appoint more than one person as an attorney under an LPA. You can also write up an advance decision that will be applied after you lose mental capacity.

When deciding whether something is in the individual’s best interest, the MCA 2005 set out a non-exhaustive checklist to consider, some examples given are:

  • encourage participation – do whatever’s possible to permit or encourage the person to take part
  • identify all relevant circumstances – try to identify the things the individual lacking capacity would take into account if they were making the decision themselves
  • find out the person’s views – including their past and present wishes and feelings, and any beliefs or values
  • avoid discrimination – do not make assumptions on the basis of age, appearance, condition or behaviour
  • assess whether the person might regain capacity – if they might, could the decision be postponed?

The Act also states that it is vital to consult with others about what is in the individual’s best interests, for example:

  • anyone previously named by the individual
  • anyone engaged in caring for them
  • close relatives and friends
  • any attorney appointed under a Lasting Power of Attorney
  • any deputy appointed by the Court of Protection to make decisions for the person

This person must also consider any advance decisions/statements made by you. As defined by the Act, an advance statement is a written statement that sets down a person’s preferences, wishes, beliefs and values regarding their future care. Although this statement is not legally binding, it will give the decision maker a better idea of what might be in your best interests. On the other hand, an advance decision is a legally binding decision that allows someone aged 18 or over, while still capable, to refuse specified medical treatment for a time in the future when they may lack the capacity to consent to or refuse that treatment.

As an advance decision is legally binding, there are criteria to fulfil in order for it to be valid. These are that: it must be in writing, signed and witnessed, and must state clearly that the decision remains applicable even if the person’s life is at risk. It must also be applicable in the current circumstances. One example where advance decisions/statements can prove particularly helpful is when deciding whether to end life-sustaining treatment – if you have specifically stated that you do not wish to be on life-sustaining treatment in an advance decision, then the person deciding on your behalf must respect this decision.

Procedures for disputes

The Court of Protection oversees the operation of the MCA 2005 and deals with all issues, including financial and serious healthcare matters, concerning people who lack mental capacity. This means that a case concerning the MCA 2005 will not go to the Crown Court/High Court – it goes directly to the Court of Protection. Any appeals from the Court of Protection will go to the Court of Appeal or Supreme Court.

You or your representative will need to apply to the Court if permission is needed to make decisions about your health, welfare, financial affairs or property. The court also aims to resolve all disputes where there are disagreements as to what’s in the person’s best interests, be it treatment choices or welfare. Some examples of the cases dealt with by the Court of Protection are: whether the NHS should withdraw treatment, whether a serious medical treatment decision is in a person’s best interests, or whether it’s in a person’s best interests to be deprived of their liberty.

Family members, as well as advocates and healthcare professionals involved in the decision-making process, can start a claim at the Court of Protection. There is a cost for bringing a claim, however, you might be able to get an application fee exemption under certain circumstances, and provided if you are eligible, legal aid can also cover any legal expenses in this area of law.

For more information on this topic, please see:


To summarise, this article covers the basics of the Mental Capacity Act 2005 by explaining what mental capacity means under the Act, the role of mental capacity assessments, decision-making when you lack capacity and how to start a dispute arising out of the MCA 2005 at the Court of Protection. As mentioned above, a person can lose capacity at any time, and sometimes unexpectedly. Therefore, knowing your rights under this Act is important for you and those around you.

This article is intended for guidance only and ‘must not’ be relied upon for specific advice.


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