Authored By: Tanya Madziva
BPP University
Montgomery1 is the landmark decision of the UK Supreme Court, delivered in the joint judgment of Lord Kerr and Lord Reed, concerning the law of medical negligence and, specifically, the doctrine of informed consent in clinical practice. It reshaped the legal test governing a doctor’s duty to disclose risks associated with treatment, departing from the paternalistic standard established in Sidaway2, which itself derived from the Bolam test3, the test for assessing clinical negligence more broadly. The Supreme Court held that patients must be informed of any material risks inherent in the treatment, assessed from the perspective of a reasonable patient rather than a body of medical opinion. Montgomery moved the doctor-patient relationship away from paternalism and towards greater respect for patient autonomy, dignity, and self-determination. It remains a patient-centred standard that continues to influence medical law and consent today.
Facts of the Case
The appellant, Nadine Montgomery, was a patient of Dr McLellan, a consultant obstetrician and gynaecologist employed by Lanarkshire Health Board (the respondent). Mrs Montgomery was of small stature and suffered from insulin-dependent diabetes. This meant her pregnancy was high risk, and she therefore attended Dr McLellan’s clinic regularly.4 Diabetic mothers are more likely to carry larger babies, so the baby’s shoulders may become too wide to pass through in a vaginal delivery. This is known as shoulder dystocia (SD), which can occur in 9–10% of diabetic pregnancies and result in serious harm to mother and child.5
Mrs Montgomery underwent fortnightly ultrasounds.6 At her final scan, her baby’s estimated weight fell below the threshold at which Dr McLellan would normally offer an elective caesarean section (c-section).7 Throughout the pregnancy, Mrs Montgomery raised concerns about the size of her baby and her ability to deliver vaginally, but did not ask specific questions concerning risks.8 Dr McLellan only raised the risk of SD with diabetic patients if specifically asked. She deemed the risk minor and considered that disclosure would prompt women to request a c-section, which she regarded as contrary to their interests. Consequently, Mrs Montgomery was never informed of the risks or offered a c-section.9
Labour was induced on 1 October 1999, by which point the baby’s birth weight (4.25kg) exceeded Dr McLellan’s threshold for offering a c-section.10 During delivery, the baby’s head failed to descend naturally, requiring the use of forceps, after which the baby’s shoulder became impacted.11 Emergency measures followed before the baby was eventually delivered. During the twelve minutes between the baby’s head emerging and full delivery, the umbilical cord was occluded, depriving the baby of oxygen.12 As a result, the baby was born with cerebral palsy and Erb’s palsy.13 Mrs Montgomery subsequently raised proceedings, alleging that Dr McLellan had negligently failed to advise her of the risk of SD and of the alternative (c-section).14
Legal Issues
Issue 1: Whether the Bolam test continues to apply to a doctor’s duty to advise a patient of risks inherent in a proposed treatment.
Issue 2: Whether, in determining what risks a doctor must disclose to a patient, the test should be based on the perspective of the reasonable doctor or that of the reasonable patient.
Issue 3: Whether the “but for” test or the House of Lords approach in Chester15 should be applied when a patient has not been advised of a material risk which subsequently materialises.
Arguments Presented
The appellant contended that the Bolam test should no longer govern a doctor’s duty to advise patients of risks inherent in treatment. She invited the Court to depart from Sidaway16, relying instead on the reasonable-patient approach articulated by Lord Scarman in Sidaway and subsequently applied by Lord Woolf MR in Pearce17. She further relied on the High Court of Australia’s reformulation in Rogers18, which assessed materiality by reference to what a reasonable patient, or a patient known to the doctor to attach particular significance to a risk, would wish to know. On causation, she argued in the alternative that, even absent conventional “but for” causation, liability could be established under the approach in Chester19. She also invoked the value of personal autonomy underpinning Article 8 of the European Convention on Human Rights (ECHR).
The respondent defended Dr McLellan’s conduct by reference to Sidaway20 and the equivalent Scottish authority, Hunter21, arguing that non-disclosure of the risk of SD accorded with a responsible body of medical opinion and therefore satisfied the Bolam and Hunter standard. It relied on expert evidence supporting Dr McLellan’s clinical judgment that the risk of grave adverse outcome was minimal, and on the Lord Ordinary’s finding that Mrs Montgomery would not, in any event, have elected a caesarean section had she been advised of the risk. The Board further sought to distinguish Chester22 on the basis that childbirth, unlike elective surgery, could not be deferred, and it urged the Supreme Court to exercise restraint before disturbing concurrent findings of fact reached by the courts below.
Court Reasoning and Analysis
The Court’s reasoning proceeds in identifiable stages. First, Lord Kerr and Lord Reed re-read the five speeches in Sidaway, showing that the case was never a unanimous endorsement of Bolam in the disclosure context. Only Lord Diplock applied it without qualification, while Lord Scarman and Lord Templeman reasoned from patient autonomy toward an independent materiality test, and Lord Bridge occupied an unstable middle position. This disaggregation undermines the assumption, relied on by the Scottish courts below, that Sidaway settled the law in favour of professional judgment.
Second, the Court identifies internal weaknesses in the Bolam model itself. The “questioning exception” is logically unstable: if medical opinion determines what must be disclosed, a patient’s question cannot rationally alter that opinion, so the exception silently contradicts the rule it modifies. The Court also finds the reliance on patient questioning perverse in practice, since the patients least equipped to ask precise questions are those most in need of information. This matters because the Court demonstrates that Bolam-based reasoning collapses under its own logic, rather than merely preferring a rival precedent.
Third, the Court turns to social context, which justifies the shift: patients have moved from passive recipients of care to autonomous rights-holders, a change reinforced by the values of self-determination underlying Article 8 ECHR. The competing public interest, that disclosure could produce defensive medicine and unpredictable litigation, is acknowledged but balanced in favour of autonomy, with reduced predictability accepted as a tolerable cost. The “therapeutic exception” survives as a narrow safety valve, but not to override patient choice.
Finally, the Court reframes causation. The lower courts asked whether Mrs Montgomery would have chosen a c-section had she been warned only of rare, grave consequences. This was the wrong counterfactual, since the duty now extends to the risk of SD itself. Finding the Lord Ordinary’s causation analysis flawed for failing to consider Dr McLellan’s own evidence, the Court establishes “but for” causation on the corrected framework, expressly declining to resolve whether Chester23 could ground causation more broadly.
Decision
The Court ruled unanimously for Mrs Montgomery. The ratio decidendi is that an adult patient of sound mind is entitled to decide which of the available forms of treatment to undergo. Therefore, a doctor is under a duty of care to ensure that the patient is informed of material risks involved in treatment, and of any reasonable alternatives. A risk is material if a reasonable person in the patient’s particular position would likely attach significance to it, or if the doctor is or should be aware that the patient would. The Bolam test does not govern this duty. The duty is subject only to two limited exceptions: (1) where the doctor reasonably considers disclosure seriously detrimental to the patient’s health (the therapeutic exception), and (2) circumstances of necessity, such as an unconscious patient or an emergency.
Critical Analysis
Montgomery replaced professional paternalism with a patient-centred materiality test.24 Academic commentary has broadly welcomed this shift. Hobson describes the decision as closing the door on Bolam in the disclosure context, correcting what had become an increasingly artificial application of a professional standard to what a patient should be told.25 Reid similarly frames the case as vindicating “the rights of the reasonable patient,” situating it within a longer trajectory of autonomy-based reasoning traceable through Chester and Article 8 jurisprudence.26
Lord Kerr and Lord Reed openly acknowledge that English courts had already quietly abandoned Bolam in practice since Pearce, and that Montgomery simply confirms a shift the lower courts had already made.27 This transparency strengthens the decision’s legitimacy as an incremental development of the common law rather than a judicial leap, though it also invites the observation that the Supreme Court was, in some respects, catching up with practice rather than leading it.
Strength of Reasoning
The reasoning is not without weaknesses. Commentators have criticised as inaccurate the Court’s analogy between patients and “consumers exercising choices.”28 Consumer law scholars suggest that disclosure regimes frequently fail to produce genuinely informed decisions, given asymmetries of expertise, time pressure, and emotional strain, conditions equally present in a delivery room. If the analogy is imperfect commercially, its transplant into medical consent may overstate what disclosure alone achieves, particularly for patients who are frightened, in pain, or lack the literacy to weigh a 9–10% risk meaningfully.
There has also been clinical criticism of the judgment’s evidentiary basis. The Chauhans argue that the Court’s reasoning engages only limitedly with the epidemiological evidence on SD, and they question how “informed consent” can be operationalised consistently without corresponding clinical guidance on what must be disclosed.29 This is a genuine practical gap between the legal standard and clinical protocol, leaving front-line application uncertain.
Wider Impact and Subsequent Retreat
The clearest test of Montgomery’s durability came in McCulloch30, where the Supreme Court was asked whether the Montgomery test governed which “reasonable alternative treatments” a doctor must discuss with a patient. The Court held that what counts as a reasonable alternative in the first place remains governed by Bolam, with Montgomery’s patient-centred materiality test applying only once a treatment has already been identified as reasonable. Commentators have described this as a reversion and a limiting of Montgomery’s reach, with the risk of subtly reintroducing “doctor knows best” by giving clinicians a Bolam-protected function over which options reach the patient.31
More than a decade on, the balance between autonomy and professional judgment remains genuinely unresolved. Montgomery succeeded in redefining how risks are communicated, but McCulloch shows that the profession retains substantial control over which options are communicated in the first place.
Conclusion
Montgomery decisively shifted the law of consent from professional paternalism toward patient autonomy, replacing Bolam with a reasonable-patient materiality test for risk disclosure.32 Its lasting contribution is the structural distinction between clinical judgment (still governed by Bolam) and advisory judgment (now patient-centred), achieved through rigorous internal critique rather than mere precedent preference. However, McCulloch33 has since confined this reach, restoring Bolam to determining which alternatives count as “reasonable”. This means doctors retain the meaningful gatekeeping power that Montgomery sought to dismantle.
Footnote(S):
1 Montgomery v Lanarkshire Health Board, [2015] UKSC 11.
2 Sidaway v Board of Governors of the Bethlem Royal Hospital [1985] AC 871.
3 Bolam v Friern Hospital Management Committee [1957] 1 WLR 582.
4 ibid [6 – 7].
5 ibid [8 – 9], [12 – 13].
6 ibid [14].
7 ibid [14 – 15].
8 ibid [17].
9 ibid [13], [17].
10 ibid [15 -16].
11 ibid [20].
12 ibid [22].
13 Ibid.
14 Ibid [1 – 2].
15 Chester v Afshar [2005] 1 AC 134.
16 Sidaway (n 2).
17 Pearce v United Bristol Healthcare NHS Trust [1999] PIQR P 53.
18 Rogers v Whitaker (1992) 175 CLR 479.
19 Chester (n 15).
20 Sidaway (n 2).
21 Hunter v Hanley 1955 SC 200.
22 Chester (n 15).
23 Ibid.
24 Montgomery (n 1) [86 – 87].
25 Charles Hobson, ‘No (,) More Bolam Please: Montgomery v Lanarkshire Health Board’ (2016) 79 Modern Law Review 488.
26 Elspeth Reid, ‘Montgomery v Lanarkshire Health Board and the Rights of the Reasonable Patient’ (2015) 19 Edinburgh Law Review 360.
27 Montgomery (n 1) [63], [86].
28 Emily Jackson, ‘Challenging the Comparison in Montgomery Between Patients and “Consumers Exercising Choices”‘ (2021) 29 Medical Law Review 595.
29 Rohan Chauhan and Suneet Chauhan, ‘Montgomery v Lanarkshire Health Board: A Paradigm Shift’ (2017) 124 BJOG 1152.
30 McCulloch v Forth Valley Health Board [2023] UKSC 26.
31 John-Paul Swoboda and Chris Fleming, ‘McCulloch v Forth Valley Health Board [2023] UKSC 26: Montgomery Revisited’ (Clinical Negligence Law, 18 July 2023); Weightmans, ‘McCulloch v Forth Valley Health Board [2023] UKSC 26 — Does “Doctor Know Best”?’ (20 July 2023).
32 Montgomery (n 1) [86 – 87].
33 McCulloch (n 30).
Bibliography
Primary Sources
Cases
Bolam v Friern Hospital Management Committee [1957] 1 WLR 582
Chester v Afshar [2005] 1 AC 134
Hunter v Hanley 1955 SC 200
McCulloch v Forth Valley Health Board [2023] UKSC 26
Montgomery v Lanarkshire Health Board [2015] UKSC 11
Pearce v United Bristol Healthcare NHS Trust [1999] PIQR P 53
Rogers v Whitaker (1992) 175 CLR 479
Sidaway v Board of Governors of the Bethlem Royal Hospital [1985] AC 871
Secondary Sources
Chauhan R and Chauhan S, ‘Montgomery v Lanarkshire Health Board: A Paradigm Shift’ (2017) 124 BJOG 1152
Hobson C, ‘No (,) More Bolam Please: Montgomery v Lanarkshire Health Board’ (2016) 79 Modern Law Review 488
Jackson E, ‘Challenging the Comparison in Montgomery Between Patients and “Consumers Exercising Choices”’ (2021) 29 Medical Law Review 595
Reid E, ‘Montgomery v Lanarkshire Health Board and the Rights of the Reasonable Patient’ (2015) 19 Edinburgh Law Review 360
Swoboda J-P and Fleming C, ‘McCulloch and others v Forth Valley Health Board [2023] UKSC 26: Montgomery Revisited’ (Clinical Negligence Law, 18 July 2023)
Weightmans, ‘McCulloch v Forth Valley Health Board [2023] UKSC 26 — Does “Doctor Know Best”?’ (Weightmans, 20 July 2023)
