While nurses may frequently refer to the patient’s ‘best interests’, it is not always clear what this means. The definition of best interests is often complicated by the fact that it can having different meanings depending on whether it is used in a legal or ethical sense (Taylor, 2016).

The Nursing and Midwifery Council’s (2018) Code encourages nurses to ‘act in the best interests of people at all times’. This requires nurses to understand:

This article considers the nature of best interests from a legal and ethical perspective and considers what this means for the decisions nurses make and the ways in which they might act in practise.

Legal best interests

Nurses must consider the legal meaning of best interests above any other considerations, since they may be held liable for their actions both professionally and under the law.

Under the Mental Capacity Act 2005, people with capacity over the age of 16 can make whatever decisions they deem fit about their own health and care, even if that decision may appear unwise to others, because everyone is assumed to have capacity unless it is proven otherwise. Staff working in health and social care cannot treat people differently even if they disagree with their medical choices. This means that people have the right to determine what is in their own best interests, as Lord Keith in Airedale NHS Trust v Bland [1993] stated:

However, when people are determined to not have capacity, any specific decision about their immediate or ongoing care has to be made by someone else. The Mental Capacity Act 2005 considers this and establishes some rules to guide the process of determining whether a person has capacity:

• the decision must not be based on any unjustified assumptions
• the decision should consider all relevant circumstances
• if the person might recover capacity and the decision can be delayed, it should be
• the person should be supported to be part of the decision making wherever reasonably practical
• the person’s known previous wishes, beliefs and values should inform the decision
• any legal representative or individual with an interest in the person’s welfare should be consulted if practical and appropriate

The law appears to identify best interests as a concept which is aligned with the values and beliefs of the individual rather than as an objective medical concept or the option that prolongs life. During Aintree University Hospitals NHS Foundation Trust v James [2013], it was established that it was not in the patient’s best interests to undergo futile treatment even if this decision results in their death.

In this ruling, Lady Hale established three elements which apply to the legal view of best interests:

1. the decision reflects a holistic view of the individual’s welfare
2. any decision should be person-centred, taking account of their likely attitude to the proposed treatment
3. it considers what the likely outcome will be for the person

The legal view of best interests is complex, with case law demonstrating that decisions are very situational and dependent on the nature of the case, the people involved and the relative importance of the decision being made (Clough, 2016).

Ethical best interests

In the ethical context, best interests can be difficult to define because they are personal to the individual. What one person considers to be in their best interests, another will consider to be the opposite. A commonly used example is that of an adult Jehovah’s witness who refuses a blood transfusion, because it is against their beliefs (Jehovah’s Witness, 2024). However, for most people who are in a life-threatening situation or undergoing surgery, accepting a blood transfusion would be considered to be in their best interests.

This example demonstrates the issues that can occur when defining best interests. While best interests can be personal and subjective, it can also be measurable and objective. In the previous example, the decision to refuse a blood transfusion is subjective and based on faith, whereas some may make the objective decision to accept a transfusion based on survival.

Singer (2015) explained objective best interests by saying that a stone cannot have interests because a stone cannot suffer, while a mouse may have interests because it can. It is reasonable to suggest that most living things would make decisions to maximise good and avoid pain (Moss et al, 2020). Nurses can make decisions for and with patients on a daily basis, for example how they choose to position someone in bed or in the provision of pain relief, and play a key role in supporting patients and families when meeting their best interests.

People may feel certain choice are in their best interests, which are not entirely objective and do not relate to medical decisions in the technical sense (Benjamin and Curtis, 2010). Medical interests in the technical sense are on the opposite spectrum to critical interests, which concern dignity (as defined by the patient), being thought well of, friendship and being able to make congruent life choices (Dworkin, 1978; Ellis, 2020). Critical interests are essentially the things that make us human.