C-8 Best Interests decisions
Last updated: 1 September 2025
All healthcare activities require consent from the patient, and any activity undertaken without permission is an assault. This remains true even if the person cannot consent. The Mental Capacity Act 2005 protects the person’s autonomy and protects the healthcare professional from being charged for assault by setting out a way to obtain consent. Many patients with more complex disabilities and high rehabilitation needs have cognitive impairment and lack the mental capacity to make decisions about their health and welfare; they will usually also lack the ability to make significant decisions about their financial and property affairs. Therefore, a rehabilitation professional must consider their patient’s mental capacity before initiating a treatment programme carrying significant risk or other costs; evidence shows that many patients evidently lacking capacity are not even assessed, and staff continue as if they can consent.
Crucially, they must also know how to legitimise their treatment using the Best Interests process in the Mental Capacity Act 2005. Every professional must possess this competency, and I outline the expertise required. The critical knowledge and skills are all part of good clinical practice: a patient-centred approach, shared decision-making and considering problems holistically. It does not require legal expertise as it is based on common sense and good clinical standards. I have discussed the use of the Mental Capacity Act in more detail in a blog post.
Table of Contents
The competency - Best Interests decisions
The competency is “Able to set up, chair, negotiate and document a best interests meeting (for a patient lacking mental capacity).” The competency is centred on one specific feature of the Mental Capacity Act 2005, chosen because it is observable and requires a good understanding of the Act. Still, it is intended to ensure compliance with the Act in all clinical practice, and the additional comment highlights this: “Needs full understanding and knowledge of Mental Capacity Act 2005. This applies to all decisions, not only major medical treatment decisions.” The Act does not require a meeting about every decision; in almost all cases, the professional can make nearly all decisions without any prolonged or broad discussion. A document detailing some indicative behaviours, knowledge, skills, and helpful references is available.
Introduction. Why is this competency needed?
Healthcare involves performing various tasks on patients, such as taking a medical history, conducting a clinical examination, drawing blood, undertaking more complex investigations, performing surgeries, administering medications, and teaching them how to walk, among others. These activities can only legally occur if the person consents. Consent can be implied and does not typically require a written document in most situations. Nonetheless, undertaking an activity without permission constitutes an assault, and consent legitimises the assault.
No one can consent on behalf of another unless the person has legally authorised them through a lasting power of attorney or a court has appointed a deputy to act on their behalf. A family member cannot grant permission, even if they claim to be “next of kin”; “Being identified as your next of kin does not, however, give anyone the right to make decisions about your care, or to give or refuse consent to treatment on your behalf.” [The Gazette Official Public Record] It is vital to realise that the ‘next of kin’ has no legal status.
The Mental Capacity Act 2005 provides a legitimate way to authorise healthcare actions when someone cannot consent. The person undertaking the activity should always consider whether the patient agrees. In most situations, this is straightforward. Nonetheless, every healthcare professional must be familiar with the main features of the Act, and this competency focuses on making significant decisions when someone lacks capacity. Similar Acts apply in Scotland and Northern Ireland.
Detailed information and guidance are readily available, such as a Code of Practice issued by the Lord Chancellor, Guidance for providers published by the Care Quality Commission in 2011, guidance from the NHS, a Mental Capacity Act toolkit from the BMA, and online courses, for example, from the Social Care Institute for Excellence. The Act itself is also available online.
Assessing capacity
I have written a review of capacity assessment, which provides more detailed information than is presented here.
Capacity is specific to the issue; it is not a generic matter, and someone may be able to make some decisions but not others. No standardised or ‘objective’ test of a person’s decision capacity exists. It is rarely necessary or appropriate to seek advice from a clinical psychologist or someone from outside the team. If required, it is advisable to seek a second opinion from a member of your team.
The Act also states that the default position is that someone has capacity until proven otherwise. The Act uses the word assume, but a more accurate term is, presume; assuming capacity without testing a person’s capacity is dangerous.
The Act sets out four questions that need to be considered, and if the person fails on any one test, they are judged to lack capacity:
- Can they understand relevant information?
- Can they retain it long enough to decide?
- Can they use or weigh up the information to make a decision?
- Can they communicate the decision?
Unsurprisingly, the most challenging question to answer, and the most contentious, is about the use of the information. One must accept that people are allowed to make unwise decisions. One approach to judging this is to ask the person to explain their decision. One can refer to it as a reasoned decision if they have used relevant evidence and not relied on unjustifiable beliefs or extraneous factors.
The best way to become good at assessing capacity is to practice on many patients, including those you think to have total capacity. You may find that your uncritical and untested assumption of capacity needs to be corrected. A Mind Map showing practical aspects of the Act is displayed below.
Best Interests
Deciding in a person’s best interests uses the same process as good clinical practice and shared decision-making. It is no different from determining a treatment or course of action with a patient who has capacity, except that you put yourself in the person’s place and use their thought processes and factors they would consider essential.
I have reviewed the different approaches available when making decisions on behalf of someone lacking the capacity, and I concluded that the UK best interests process was the best option. The review outlines how to make a best interests decision, focusing on the most challenging cases, but also applies to all decisions when a person cannot agree. Several essential principles should guide your daily practice.
Proportionality
The effort devoted to the process must be proportionate to the risks, benefits, irreversibility of action, and other factors involved. Giving morphine for postoperative pain or paracetamol for a headache are minor decisions and rarely require any process. Most routine care interventions are not subject to controversy.
In contrast, deciding not to continue a life-sustaining treatment is a significant decision. Some decisions, such as inserting a gastrostomy tube in an unconscious patient, may be substantial, depending on the context. It may necessitate long-term gastrostomy feeding for the patient. One must consider not only immediate risks and benefits but longer-term implications.
Sources of information.
If there is one, an appropriately appointed deputy (attorney) is the only required source. In all other situations, when seeking information to guide a decision, one must consider as wide a range of sources as feasible, given the circumstances and context. No one is a preferred source, and no one can restrict you from approaching whom you want. This does not mean you ask anyone; it does mean you consider whether some other people should be approached. Remember that no privilege is given to people who self-identify as next of kin.
Information can be in any form: written, copies of letters, emails or text messages, video recordings, or what someone tells you. Informants should not be asked to sign anything, but it does help if they write down what they know. Always ask if there is an Advance Decision to Refuse Treatment or Advance Statement.
The MindMap below provides additional guidance.
Strategic decisions.
The Act concentrates on making a single decision. The number of decisions made every day on patients lacking capacity is enormous. One invaluable way to resolve this is to make strategic decisions for anyone whose incapacity is likely to be prolonged. This is similar to Advance Care Planning, where one considers actual or potential future situations in which decisions must be made if they arise.
Two examples may help:
- Investigating a new symptom of a potentially serious but treatable condition.
A strategic decision should be made on whether to start an investigation. If an inquiry with potential treatment is agreed upon, all future actions on the pathway can also be considered in the person’s best interests. This should be reviewed if new information arises, altering the initial considerations but otherwise allowing the process to continue. - Limiting response to acute illness.
A strategic decision can be made about the extent of intervention. This might include, for example, not transferring someone from home to the hospital or into an intensive care unit within a hospital. This will have an associated plan for good palliative care under all circumstances, which can be reviewed. This is a version of the ReSPECT process.
Recording information.
Much valuable information is provided by others spontaneously as they interact with staff. Any information provided informally should be recorded in the clinical record. It may save much effort or be helpful in an emergency, and it is less prone to bias as it is given spontaneously.
Ideally, the medical record should have a section devoted to information about the person so that it can be found quickly.
Justifying the decision.
Typically, if a record of a significant best-interest decision made in a meeting is kept —and often it is not —it is challenging to discover how the decision was made, why this decision and not the other. It may be obvious to anyone present, but it will be a mystery to anyone reviewing or questioning the decision.
Judges deciding on continuing medical treatment in people with prolonged disorder of consciousness explicitly explain their reasoning and justify their conclusion. A recent decision by the Honourable Mr Justice Mckenrick in a case ([2025] EWCOP 17 (T3) re: PK), sets out in paragraph 62 an exemplary justification for his decision. We should do the same.
However, in my discussion of his case and one other (see Holistic best interests in court), I point out that we have no systematic approach to the “other factors that he would be likely to consider if he were able to do so”. I suggest, in the context of life-sustaining treatment, one systematic approach, but it does not generalise to most decisions. I hope a check-list of other factors may be developed.
Embedding the Mental Capacity Act in practice.
Unfortunately, the Mental Capacity Act has become inextricably associated with two specific circumstances: the application of the Deprivation of Liberty Safeguarding (DOLS) process and the withdrawal of clinically assisted nutrition and hydration (CANH) from people in a prolonged disorder of consciousness (PDOC). It is also associated with hospital consent forms, usually focused on operations.
It should be integral to all clinical activities. Some reasons it is not embedded are illustrated in the MindMap below.
Conclusion
All rehabilitation professionals need to know, understand and use the Mental Capacity Act 2005, if only because it is the only way to legitimise their actions with any patient who cannot give consent. This competency focuses on one activity required by the Act: deciding a person’s best interests. However, this involves familiarity with all aspects of the Act. The Act serves as a formal legal guide to best clinical practice, ensuring that a decision considers the person’s past and present wishes, feelings, beliefs, values and other factors; it also considers the views of carers. The greatest challenges in more complex cases are finding the documented evidence needed to arrive at a decision and then understand how the people present reached their decision.
