All healthcare professionals should be aware of the decision of Montgomery v Lanarkshire Health Board, handed down by the Supreme Court on 11 March 2015.

The duty of a doctor to warn a patient of risks in treatment is not to be determined by reference to the actions of a reasonable and responsible body of clinicians. The test is one of materiality – in other words, whether the patient is aware of material risks. A risk is material if a reasonable person in the patient’s position would be likely to attach significance to the risk or if the doctor is or should be aware that the particular patient would be likely to attach significance to it. This is not an exercise of statistical possibilities, but a reflection of the impact of those risks on the patient.

This judgement aligns the law with the guidance on consent set out by the GMC, and reinforces the right of competent adults to make informed decisions about matters affecting their treatment, including the benefits and risks of alternative and variant treatments.

It is inevitable that the limits of the redefined duty will be further tested by the Courts. However, as matters stand it is necessary to ensure that healthcare professionals are aware of the need to discuss all risks and options which the patient considers, or is likely to consider, to be materially significant. Clear and unambiguous notes of discussions need to be maintained, and pro forma information leaflets may need to be reviewed.