On 12 March 2015, the Supreme Court in London delivered arguably the most significant decision in the field of medical negligence for a generation. The case ofMontgomery v Lanarkshire Health Board has resulted in a momentous advancement in relation to the court's consideration of arguments surrounding consent to medical treatment.

Although the facts of the case relate to a complex and high value birth damage claim and the issue of whether a Caesarian Section should have been offered to a high-risk diabetic mother, the decision is applicable in all medical negligence claims where a patient's consent requires to be obtained before treatment can be undertaken.

Put briefly, the court has stated that a doctor is under a duty to take reasonable care to ensure that their patient is aware of any material risks involved in any recommended treatment and of any reasonable alternatives. When assessing whether something is material, it is for the court to look at the particular circumstances and assess whether a reasonable person in the patient's position would be likely to attach significance to the risk, or the doctor is (or should be) reasonably aware that this particular patient would be likely to attach significance to the risk.

By allowing the Appeal, it has been recognised that the Supreme Court is reflecting what the General Medical Council (GMC) has been setting out in its guidance on consent to medical treatment for many years - to fully advise a patient of the options for treatment, the risks of each option and the benefits of the option, and it is then for the patient, not the doctor, to advise which option they wish to choose.

A "patient-focused test", as it has been called, is not something the Supreme Court has applied retrospectively when reaching this decision. The court has simply applied the standards of the GMC at the relevant time to the facts of the case and concluded that no longer is the relationship between the doctor and the patient one of medical paternalism. Instead, it is a relationship where the patient is treated as an adult capable of understanding the potential benefits, risks, burdens and side-effects of each available option together with the doctor's recommendation for a particular option, before the patient accepts responsibility for making a decision and will require to live with the consequences of that decision.

 In terms of what the future will hold, this decision is likely to result in a number of existing medical negligence actions being developed to introduce a consent argument and new actions being raised, either based solely on the consenting process or adding this claim to the allegations of negligence made against a medical professional.