The Supreme Court decision in the case of Montgomery v. Lanarkshire Health Board [2015] UKSC 11, 11 March 2015 sounds the death knell for Sidaway. The Supreme Court comprised of 7 Law Lords has now unequivocally said that Sidaway should not be followed in medical cases where consent is in issue. Allowing the appeal from the Scottish courts by a woman whose baby suffered shoulder dystocia in labour, the Supreme Court held that women have a right to information about ‘any material risk’ in order to make autonomous decisions about how to give birth.

The facts

Mrs Montgomery was a pregnant woman with diabetes and small in build. She was carrying a large baby but was not informed by her obstetrician of the chance of shoulder dystocia. During delivery there was a 12 minute delay in freeing the baby’s shoulders during which her son was starved of oxygen. He sustained a brain injury and paralysis of his arm caused by the force used in pulling him out.

The claim

The principal claim was against her obstetrician for failing to give proper warnings. The mother said she should have been warned of the risks of shoulder dystocia, and her evidence was that, had she been so warned, she should have been offered and would have asked for a caesarean section.

The defence

Although the mother had repeatedly expressed concerns about giving birth vaginally, the obstetrician said that she routinely chose not to explain the risk of shoulder dystocia to diabetic women because the risk of serious injury to the baby was very small and that if she did explain it, ‘then everyone would ask for a caesarean section’, and in this she was supported by some of the experts who gave evidence at trial.

Sidaway revisited

The Scottish courts decided that Sidaway was determinative of the question but the Supreme Court undertook a comprehensive review of the law after Sidaway. Looking at cases such as Pearce and Chester v Afshar it was clear that there has been a move away from Sidaway and its adoption of the Bolam test. The decision brings English and Scottish law into line with that of the United States and other common law jurisdictions by separating the question of informed consent from the traditional test for clinical negligence.

‘Montgomery rules’

The Court expressed the legal duty on doctors as follows [87]:

The doctor is therefore under a duty to take reasonable care to ensure that the patient is aware of any material risks involved in any recommended treatment, and of any reasonable alternative or variant treatments. The test of materiality is whether, 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 the doctor is or should reasonably be aware that the particular patient would be likely to attach significance to it.’

It is no longer appropriate to assess the adequacy of a doctor’s advice or warnings according to the standards of a reasonable medical professional. The correct approach is whether the patient would attach significance to the risk. As stated in the judgment at [75]

….patients are now widely regarded as persons holding rights, rather than as the passive recipients of the care of the medical profession…..Gone are the days when it was thought that, on becoming pregnant, a woman lost, not only her capacity, but also her right to act as a genuinely autonomous human being.

Strasbourg jurisprudence also recognises the duty to involve a patient in treatment decisions (see Tysiac v Poland (2007) 45 EHRR 42)

Therapeutic exception

There is however, a limited exception to the rule in Montgomery when a doctor is entitled to withhold from the patient information as to a risk if she reasonably considers that its disclosure would be seriously detrimental to the patient’s health. The Court stressed that it should not be use to interfere with the autonomy of a patient where the doctor fears that the patient will make an unwise choice.


Having established a breach of duty, the claimant still has to show that if she had been properly informed of the risks, she would have made a different decision. The Court concluded that on a proper analysis of the mother’s and the obstetrician’s evidence, it was probable that the mother would have elected to undergo a caesarean section had it been offered to her with a full explanation of the risks of shoulder dystocia.

Expanding Litigation

A significant proportion of all NHS negligence claims according to NHS Litigation Authority, ’10 Years of Maternity Claims’ relate to obstetric and maternity care (>50%). In recognising the potential for a sharp increase in litigation the Supreme Court said this [93]:

‘…in so far as the law contributes to the incidence of litigation, an approach which results in patients being aware that the outcome of treatment is uncertain and potentially dangerous, and in their taking responsibility for the ultimate choice to undergo that treatment, may be less likely to encourage recriminations and litigation, in the event of an adverse outcome, than an approach which requires patients to rely on their doctors to determine whether a risk inherent in a particular form of treatment should be incurred.’

This approach suggests that proper disclosure of risks will protect health professionals from litigation. There is also a subtle shift of emphasis in that whilst respect for patient autonomy is paramount, this in turn means that patients are ultimately responsible for their own decisions.


This decision has laid Sidaway to rest. GMC guidance on consent was quoted with approval in Montgomery. The Court highlighted the following as being of particular importance when considering consent:

Material risks [89]: “The assessment of whether a risk is material cannot be reduced to percentages. The significance of a given risk is likely to reflect a variety of factors besides its magnitude: for example, the nature of the risk, the effect which its occurrence would have upon the life of the patient, the importance to the patient of the benefits sought to be achieved by the treatment, the alternatives available, and the risks involved in those alternatives. The assessment is therefore fact-sensitive, and sensitive also to the characteristics of the patient

Dialogue [90] the doctor’s advisory role involves dialogue, the aim of which is to ensure that the patient understands the seriousness of her condition, and the anticipated benefits and risks of the proposed treatment and any reasonable alternatives, so that she is then in a position to make an informed decision. This role will only be performed effectively if the information provided is comprehensible. The doctor’s duty is not therefore fulfilled by bombarding the patient with technical information which she cannot reasonably be expected to grasp, let alone by routinely demanding her signature on a consent form”.

The Supreme Court has now clarified the law and buried the doubts that arose in UK courts where Sidaway appeared to conflict with later authorities.  The case of Montgomery rules.

Written by Nageena Khalique QC