Background What action should palliative care clinicians take if they feel that a medical treatment is ineffective but carers disagree? In the case of incapacitated adults in England and Wales, it is only lawful to withhold life sustaining treatment is it is judged to be futile or overly burdensome to the individual. Disagreements as to an individual’s best interests may involve recourse to the courts.

Methods This paper reviews the case law in this area, charting 25 years of judicial decision making on behalf of incapacitated patients receiving life-sustaining treatment.

Results Recent cases illustrate a evolution; from a deference to medical decision making to a rejection of a biomedical ‘best interests’ decision-making model. Courts now show a willingness to scrutinise what clinicians mean when they invoke the term “futile” to withhold life-sustaining treatment in a person’s best interests. The UK Supreme Court’s recent narrow interpretation of futility; “ineffective or being of no benefit to the patient ” has the potential to skew treatment decisions in favour of interventions that have little chance of producing a meaningful improvement in clinical condition.

Conclusion By rejecting the ‘medical’ view of futility the right of an incapacitated individual to have burdensome or minimally beneficial treatments withdrawn is now interwoven with the judicial interpretation of their best interests. Removing these decisions from the bedside adds additional complexity to end of life decision-making as clinicians may no longer know with certainty that their decision to withdraw life sustaining treatment is a lawful one.