“…social and legal developments ….. point away from a model of the relationship between the doctor and the patient based upon medical paternalism…” (at )
” …An adult person of sound mind is entitled to decide which, if any, of the available forms of treatment to undergo, and her consent must be obtained before treatment interfering with her bodily integrity is undertaken. 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.” (at )
Published yesterday was the decision of the United Kingdom Supreme Court in Montgomery v Lanarkshire Health Board  UKSC 11. The decision appears to formally shift UK law to the 1992 Australian position since Rogers v Whitaker, such that the Bolam test ought not be applied in warning cases: .
The primary judgment was written by Lord Kerr & Lord Reed, with four others agreeing. Lady Hale wrote supplementary reasons, also agreeing, but the comments below are taken from the primary judgment.
The asserted need to give a warning about the risk of shoulder dystocia in vaginal delivery was the factual background: . At  –  the Court discussed Rogers v Whitaker, describing as ‘undoubtedly right’ the attention to proactive and reactive duties in the Australian decision.
The substantive discussion beginning at . At  the Court comments on the rise of personal autonomy:
Since Sidaway, however, it has become increasingly clear that the paradigm of the doctor-patient relationship implicit in the speeches in that case has ceased to reflect the reality and complexity of the way in which healthcare services are provided, or the way in which the providers and recipients of such services view their relationship. One development which is particularly significant in the present context is that patients are now widely regarded as persons holding rights, rather than as the passive recipients of the care of the medical profession. They are also widely treated as consumers exercising choices: a viewpoint which has underpinned some of the developments in the provision of healthcare services. In addition, a wider range of healthcare professionals now provide treatment and advice of one kind or another to members of the public, either as individuals, or as members of a team drawn from different professional backgrounds (with the consequence that, although this judgment is concerned particularly with doctors, it is also relevant, mutatis mutandis, to other healthcare providers). The treatment which they can offer is now understood to depend not only upon their clinical judgment, but upon bureaucratic decisions as to such matters as resource allocation, cost-containment and hospital administration: decisions which are taken by non-medical professionals. Such decisions are generally understood within a framework of institutional rather than personal responsibilities, and are in principle susceptible to challenge under public law rather than, or in addition to, the law of delict or tort.
Quantifying the relevant risk is discussed at , the court noting that the risk relevant here was the risk of shoulder dystocia, not the risk of a particular injury from it. Like in Australia, the threshold risk cannot be reduced to a percentage: 
Interestingly at  the Court comments obiter that a person can of course decide that she does not wish to be informed of risks of injury (just as a person may choose to ignore the information leaflet enclosed with her medicine); and a doctor is not obliged to discuss the risks inherent in treatment with a person who makes it clear that she would prefer not to discuss the matter.
The therapeutic privilege issue is discussed at , framed by reference to a serious belief that disclosure would be detrimental to a patient’s health. A warning of its limited scope appears at .
Causation and hindsight bias issues were discussed briefly, the court concluding at  that had the mother been told of the risk of shoulder dystocia and had there been discussed with her dispassionately the potential consequences, and the alternative of an elective caesarean section, she would probably have elected to be delivered of her baby by caesarean section.
A short video summary of the Supreme Court decision, read by Lord Reed, is available online.