The modern view of the relationship between doctor and patient is the main focus of the UK Supreme Court decision in Montgomery v Lanarkshire Health Board [2015] UKSC 11.

The Supreme Court has confirmed that there is a legal duty on medical practitioners to take reasonable care to ensure that a patient is aware of material risks of injury inherent in any proposed treatment. The decision confirms that the previous analysis of the law by the House of Lords in the 1985 case of Sidaway v Board of Governors of the Bethlem Royal Hospital is no longer to be applied.

In Sidaway the House of Lords had decided that the question of whether particular risks should be discussed with a patient was subject to the Bolam/Hunter v Hanley test. If it was established there was a body of medical opinion that would have chosen not to discuss the risks with the patient then a doctor would not be held negligent for deciding not to do so. As a result of the decision in Montgomery that is no longer the law.

The background

In 1999 Mrs Montgomery’s son was born with severe disabilities. Delivery had become complicated by the inability of the baby’s shoulders to pass through the pelvis (an event known as shoulder dystocia) and in dealing with that difficulty her son suffered both a deprivation of oxygen and a physical injury. As a result, following his birth he was diagnosed with both cerebral palsy and Erb’s palsy.

Mrs Montgomery claimed on the basis that, as a small, diabetic woman, she had not been warned about the risks involved in a vaginal delivery and, had she been warned, she would have opted for the safer option of a caesarean section.

Mrs Montgomery’s action against the consultant responsible for her care and delivery of her son failed in the Outer and Inner Houses of the Court of Session. She appealed to the Supreme Court.

The appeal

In allowing her appeal the Supreme Court held that changes in society and in the way that health care is provided mean that it is no longer appropriate to view patients as uninformed, incapable of understanding medical matters or as being wholly dependent on information from doctors. The law must treat patients as adults capable of understanding the uncertainty of medical treatment and of accepting responsibility for the taking of risks affecting their own lives.

The court distinguished the role of the doctor when considering possible investigatory or treatment options and her role in discussing the treatment and possible alternatives with the patient. Significantly, the court held that the question of whether a risk of injury or the availability of an alternative treatment ought to be discussed with the patient is not a matter of purely professional judgement.

The extent to which an individual doctor may be inclined to discuss risks with a patient is not determined by medical learning or experience so it is not appropriate to apply the normal Hunter v Hanley (or Bolam) test for professional negligence.

The need to explain the risks involved

Consent must be obtained from a patient before any treatment interfering with her bodily integrity is undertaken. In obtaining consent the doctor must take care to ensure that the patient is aware of risks involved in the recommended treatment and of the availability of any reasonable alternative treatment.

A risk will be considered material if, in the circumstances of the particular case, a reasonable person in the patient’s position would be likely to attach significance to the risk or if the doctor ought to be aware that the particular patient would be likely to attach significance to it.

The assessment of whether a risk is material is not merely a statistical exercise but must take into account the nature of the risk, the effect the occurrence of the risk would have on the patient, the importance to the patient of the benefits of the treatment, the alternatives to the treatment and the risks involved in those alternatives. The assessment will be fact sensitive and sensitive to the characteristics of the patient.

In Mrs Montgomery’s case there was a substantial risk of shoulder dystocia. Even if the risk of grave injury to the child was relatively small it involved significant risks to the mother’s health. The consultant was aware that Mrs Montgomery had concerns about giving birth vaginally and that consultant knew or ought to have known that the risks were such as to be likely to affect the decision of patients in Mrs Montgomery’s position.

As Lady Hale puts it: “One of the problems in this case was that for too long the focus was on the risks to the baby, without also taking into account what the mother might face in the process of giving birth.”


The question remained whether, had the risks been explained, Mrs Montgomery would have opted for a caesarean section or whether she would have proceeded with a vaginal birth.

The judge at first instance and the Inner House on appeal had found that, on the evidence, she would not have opted for caesarean section. However, those judgments had only considered the reaction Mrs Montgomery would have given had she been told of the minimal risks of grave consequences for her unborn child and did not take account of her likely reaction to the wider risks to her own personal health. That was an error which justified the court looking at the issue of causation again.

The evidence taken as a whole, including evidence given by the consultant herself, clearly allowed the court to conclude that Mrs Montgomery would in fact have opted for a caesarean section had the risks of shoulder dystocia been explained to her.

Since the pursuer was successful in establishing that “but for” the failure to advise of the risks she would have chosen to deliver her son by caesarean section it was not necessary for the Supreme Court to consider whether or not she might have been able to establish causation on some other basis.

She had run a separate argument which relied on the decision in Chester v Afshar [2004] UKHL 41; [2005] 1 AC 134 as establishing that it would have been sufficient to establish causation that a risk of grave adverse consequences, of which there was ex hypothesi a duty to advise, had in fact materialised. That argument will have to wait for another day.

Rare exceptions

Although it is accepted that there will be exceptions to the rule – for example where emergency treatment is to be provided or where disclosure of risks would be seriously detrimental to the patient’s health – those exceptions will be rare and doctors are warned not to seek to use them to subvert the general principle.

The Supreme Court recognises that not all healthcare providers will welcome the decision in Montgomery but they conclude that: “It is nevertheless necessary to impose legal obligations, so that even those doctors who have less skill or inclination for communication, or who are more hurried, are obliged to pause and engage in the discussion which the law requires.”

Assessing and discussing risk

The Supreme Court’s decision means that doctors will now legally be obliged to follow approach already set out in GMC guidance based on informed involvement of patients in their treatment. It is for the patient to weigh up the various risks of alternatives presented to her and to decide which, if any, of the treatment options she wants to accept.

Lady Hale suggests that this has been the position in English law for some time given that the English courts have tacitly sidelined the Sidaway approach in consent cases. The Montgomery decision puts that beyond doubt.


Douglas McGregor

Practice Development Lawyer