This chapter outlines for multi-agency practitioners what ‘best interests’ are in relation to an adult who lacks mental capacity.

Click here to view Mental Capacity Act Policy and Procedures Including Deprivation of Liberty Safeguarding (Trafford Strategic Safeguarding Partnership)


Mental Capacity


Making Decisions, SCIE

A Brief Guide to carrying out Best Interests Assessments, 39 Essex Chambers

February 2020: This chapter was amended to include a link to the most recent version of A Brief Guide to carrying out Best Interests Assessment published by 39 Essex Chambers, as linked above.

1. Introduction

If a person has been assessed as lacking capacity, any action taken or any decision made or on behalf of that person, must be made in their best interests. This is the fourth principle of the five principles of the Mental Capacity Act 2005 (MCA) (see Mental Capacity).

The person who has to make the decision is known as the ‘decision maker’. This is usually the carer responsible for day to day care, but may be a professional such as a doctor, nurse or social worker where decisions about treatment, care arrangements or accommodation have to be made.

2. What are ‘Best Interests’?

The law requires a number of factors to be considered when deciding what is in the best interests of a person who lacks capacity. The checklist below details these factors. This list is not exhaustive and the MCA Code of Practice should be referred to for more details.

  • It is important not to make assumptions about someone’s best interests merely on the basis of his or her age, appearance, condition or any aspect of their behaviour.
  • The decision maker must consider all the relevant circumstances relating to the decision in question.
  • The decision maker must consider whether the person is likely to regain capacity (for example after receiving medical treatment). If he or she is likely to, can the decision or act wait until then?
  • The decision maker must involve the person as fully as possible in the decision that is being made on their behalf.
  • If the decision concerns the provision or withdrawal of life sustaining treatment the decision maker must not be motivated by a desire to bring about the person’s death.

The decision maker must in particular consider:

  • the person’s past and present wishes and feelings (in particular if these have been written down);
  • any beliefs and values of the person (for example religious, cultural or moral) that would be likely to influence the decision in question and any other relevant factors.

As far as possible, the decision maker must consult other people if it is appropriate to do so and take into account their views as to what would be in the best interests of the person lacking capacity, especially:

  • anyone previously named by the person lacking capacity as someone to be consulted;
  • carers, close relatives or close friends or anyone else interested in the person’s welfare;
  • any attorney appointed under a Lasting Power of Attorney (LPA);
  • any deputy appointed by the Court of Protection to make decisions for the person;
  • the Independent Mental Capacity Advocate (IMCA), if appointed (see Independent Mental Capacity Advocate Service).

The decision maker must take the above steps, amongst others, and weigh up the above factors when deciding what decision or course of action is in the person’s best interests.

For decisions about serious medical treatment or certain changes of accommodation and where there is no one who fits into any of the above categories, the decision maker may need to instruct an IMCA.

3. Where there is a Dispute about Best Interests

Family and friends may not always agree about what is in the best interests of an individual. Case records should record any details of disputes, must clearly demonstrate that decisions have been based on all available evidence and have taken into account all the conflicting views. If there is a dispute, the following courses of action can help in determining what is in a person’s best interests:

  • involve an advocate who is independent of all the parties involved;
  • get a second opinion;
  • hold a formal or informal case conference;
  • go to mediation;
  • as a last resort, an application could be made to the Court of Protection for a ruling.

4. Recording

Comprehensive recording is key in all cases, but particularly in safeguarding adults cases which are likely to be the most complex and present the highest levels of risk. In such cases, full records of best interest decision making should be kept, including:

  • how the decision about the person’s best interests was reached;
  • the reasons for reaching the decision;
  • who was consulted to help decide the best interests;
  • what particular factors were taken into account;
  • if written requests from person concerned were not followed, why not;
  • the content and results of any disputes;
  • what has been decided in the person’s best interests and reasons for that decision.

People lacking mental capacity have the same rights as those with capacity to have their outcomes realised. Although it may be challenging, a good best interest decision reflects the wishes, feelings, values and needs of the person.

This can also be included as an outcome measure on the safeguarding adult return forms (see Safeguarding Adults Data Returns).

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