Best interests must be centred on the person's needs not those of the family

The best interest approach was initially developed by the courts from cases concerning people who lacked mental capacity, which were brought before them for decisions on care and treatment (F v West Berkshire HA [1990]). The focus of the courts under this common-law approach was generally limited to the clinical needs of the patient, and nurses determining a patient's best interests were required only to consider the benefits of the proposed treatment against the risks and burden of the treatment.

In what is now the balance-sheet approach to best interests, if the benefits of treatment clearly outweighed the risks and burdens, then it was in the person's best interests to receive that treatment (Re A (Medical Treatment: Male Sterilisation) [2000]).

The concerns of the courts resulted in the introduction of the Mental Capacity Act 2005, which includes the following aims:

Under the Mental Capacity Act, the determination of a best interest is based on a more holistic approach, which requires nurses to consider the views and values of the person, and to consult with family and carers on their views about the person's best interests (Mental Capacity Act 2005, section 4).