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Mental Capacity and Best Interest Decision Making


This guide is written for anyone who is involved in the care and treatment of individuals who, due to illness or disability, are unable to make decisions for themselves.

Our Care team believes in a fully informed, open and honest decision making. This benefits family members, care professionals and most importantly, the individual at the core of the process.

This is a complex and often misunderstood area of law, which can lead to disputes and sadly, court action. We can provide up-to-date information, representation and advice to families, carers and professionals to ensure that any concerns are clearly addressed, avoiding conflict, delays and court action wherever possible.

The Mental Capacity Act 2005 (“the Act”) sets out the law in relation to acting and making decisions on behalf of individuals who lack the mental capacity to make a particular decision for themselves.

The Mental Capacity Act supporting Code of Practice (“the Code”) was introduced in 2007 to provide practical guidance for those involved with incapacitated adults, including Deputies and Attorneys.

The Law is applied in cases brought before the Court of Protection.

The five stautory principles
The Act and the Code are underpinned by five statutory principles that should be borne in mind in any decisions that you make, or participate in, on someone’s behalf:

  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 him to do so have been taken without success.
  3. A person is not to be treated as unable to make a decision merely because he makes 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 his best interests.
  5. Before the act is done, or the decision is made, regard must be had to whether the purpose can be achieved in a way that is less restrictive of the person’s rights and freedom of action.

The Mental Capacity Act defines a person who lacks mental capacity as someone unable to make a decision for themselves because of an impairment or disturbance of the mind or brain. However, it is important to emphasize that whether someone does or does not have ‘capacity’ is not fixed. Under the Act and the Code, capacity is clearly linked to an individual’s ability to make a particular decision at a particular time.

This means recognising when the individual you act for may have capacity to make a decision, and enabling them to do so. It also means stepping in to make decisions when the individual does lack capacity. This will depend on the nature of the decision:

  • An individual may be able to make many everyday decisions such as what to buy at the local shop.
  • More significant decisions, such as where someone should live, should begin with the presumption of capacity. A more formal mental capacity assessment will take place to assess capacity in relation to that particular decision.

An individual is deemed to lack capacity to make a particular decision where they are unable to:

  • Understand the information relevant to the decision, including the reasonably foreseeable consequences of deciding one way or another, or failing to make the decision
  • Retain that information
  • Use or weigh that information as part of the process of making the decision, or
  • Communicate their decision (by any means)

The Code provides detailed information on applying the above factors. Where an individual does lack capacity, decisions must be taken using the best interests guidance set out under section 4 of the Mental Capacity Act.

his is a decision made on behalf of someone who lacks mental capacity to decide the particular issue themselves. As we have highlighted, the more significant the decision is, the more emphasis should be placed on taking careful and considered steps to reach the final decision. A written record should be kept, including minutes of any meetings.

People involved in the care and welfare of the individual should be asked to contribute their views, but the final decision is taken by one person who is referred to as the decision maker. This is a decision made on behalf of someone who lacks mental capacity to decide the particular issue themselves.

  • consider all the relevant circumstances
  • encourage the individual to participate in making the decision as far as they are able
  • consider delaying the decision if the individual is likely to regain capacity to make the decision
  • take account of the individual’s past and present wishes, feelings, beliefs and values
  • consider the views of other people close to the individual, or nominated by the individual to be consulted

Any decision made should not:

  • be based on assumptions about an individual’s appearance, health condition or behaviour OR
  • be a decision based on ‘substituted judgement’, where you make a decision based on what you think the individual would have done, if they had capacity – their views are considered, as one of many factors listed above.

Families are often surprised and upset to discover that their views of what their loved one wants is considered but not the overriding factor. This should be made clear to family members at the earliest opportunity and the decision making process should reflect how their views were incorporated into the final decision.

The decision maker should follow the principles and the above guidance to ensure that a balanced approach is taken to decision making.

This depends on whether any authority has already been given by the individual in the form of a Lasting Power of Attorney (LPA) or Advance Decision/Directive.

If there is an authority – and it covers the decision in question, the Attorney will be the decision maker. In some circumstances a Court Order appointing a Deputy will be in place. If so, this should be referred to, to see the extent of the Deputy’s authority. If an Attorney or Deputy does not have the authority to take the decision they should still be consulted and involved in any best interest decision taken.

There are additional factors to consider when making decisions about life sustaining treatment and you should refer to the Code of Practice for further, detailed guidance or contact a member of the team for advice.

Bill has Vascular Dementia and has recently been admitted to hospital following a fall. Health professionals and family members need to decide whether Bill is safe to return home, living alone. A mental capacity assessment has been completed and Bill does not have capacity to decide where he should live. This decision should be taken on a best interests basis.

Bill had appointed his daughter Jane under a Lasting Power of Attorney for Property and Finances, but has not done a Lasting Power of Attorney for Health and Welfare, or made any advance directives.

In reality, if family members and professionals agree, this decision is often taken quite informally. However, if there was a disagreement as to where Bill should live, a formal best interests meeting should be held. As no one has the legal authority to take the decision, agreement should be reached by those involved, using the best interest guidance. If it cannot, then a Court application may be necessary.

Once an agreement has been reached, if Bill has savings over the local authority limit and is therefore self funding, Jane will be left to choose and organise his care. Jane will effectively be the ‘decision maker’ in this regard. The authority to take this decision is not given to Jane by the Lasting Power of Attorney but Jane still has a duty to act in her Father’s best interests, following the guidance in the Act and the Code.

Where the Local Authority has a duty to contribute to the care package, further best interest meetings may need to be held to agree which care home will be appropriate for Bill.

These are Advocates appointed under the Mental Capacity Act, to represent the individual concerned in the best interest decision making process, where he/she has no appropriate family or friends to consult

They are given statutory powers to fact find and meet with the individual, to ensure that the individual has representation in the decision making process.

And finally - Our care team can support and advise you in all aspects of Mental Capacity and best interests decisions.

For family and friends - We provide legal advice, support and representation throughout the care process, including best interests decisions. We compile written submissions of information for use during the decision making process and provide representation at best interest meetings.

For professionals - We deliver bespoke training on the Mental Capacity Act and on the practical application of section 4 (best interest checklist) in light of recent case law. We provide guidance for staff, including meeting pro forma and supporting notes, to give you confidence in your approach to decision making.

These are some of the words and terms you may encounter:


A person appointed under a Lasting Power of Attorney. An Attorney has the legal right to make decisions on behalf of the Donor as long as those decisions are within the scope of their authority.

Court Appointed Deputy

A person appointed by the Court of Protection. A Deputy has the legal authority to make decisions about personal welfare and/or property and financial affairs.

Mental Capacity

A person’s ability to make a decision about a particular matter at the time the decision needs to be made.

Independent Mental Capacity Advocates (IMCA)

Independent support and representation for a person who lacks capacity to make specific decisions where the person has no-one appropriate to support them. The IMCA service was established by the Mental Capacity Act 2005 and is not the same as an ordinary advocacy service.

Best Interest Decision Maker

A decision maker is a person who is responsible for deciding what is in the best interests of a person who lacks capacity.

Best interest Decisions

Any act done or decision made on behalf of a person who lacks capacity must be done or made in their best interests.

Team members

Yvonne Chapman
Senior Solicitor

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