Montgomery (Appellant) v Lanarkshire Health Board (Respondent) (Scotland)

1. Case Citation and Basic Information

Full case name: Montgomery (Appellant) v Lanarkshire Health Board (Respondent) (Scotland)
Citation: Montgomery v Lanarkshire Health Board [2015] UKSC 11; [2015] AC 1430
Court: Supreme Court of the United Kingdom
Date of judgment: 11 March 2015
Bench: Lord Neuberger, Lady Hale, Lord Kerr, Lord Clarke, Lord Wilson, Lord Reed and Lord Hodge. The principal judgment was delivered by Lord Kerr and Lord Reed, with whom Lord Neuberger, Lord Clarke, Lord Wilson and Lord Hodge agreed. Lady Hale gave a concurring judgment. 

2. Introduction

Montgomery v Lanarkshire Health Board is a landmark decision in medical negligence and informed consent. The case transformed the legal duty of doctors to disclose risks before medical treatment. Before Montgomery, disclosure of risk was often assessed through professional medical practice, particularly under the influence of Bolam v Friern Hospital Management Committee and Sidaway v Board of Governors of the Bethlem Royal Hospital. The Supreme Court rejected that paternalistic model and placed patient autonomy at the centre of consent. The case is significant because it established that doctors must take reasonable care to ensure that patients are aware of material risks and reasonable alternatives. Its lasting importance lies in shifting the law from doctor-centred judgment to patient-centred decision-making.

3. Facts of the Case

Nadine Montgomery was a pregnant woman of small stature who had diabetes. Her pregnancy was managed by Dr Dina McLellan, a consultant obstetrician employed by Lanarkshire Health Board. Maternal diabetes was clinically significant because it increased the risk that the baby would be larger than average and that vaginal delivery might be complicated by shoulder dystocia. Shoulder dystocia occurs when the baby’s shoulders become stuck during delivery after the head has emerged. It is an obstetric emergency and can lead to oxygen deprivation, physical injury, cerebral palsy, or death.

During Mrs Montgomery’s antenatal care, the risk of shoulder dystocia was known to be around 9–10% in diabetic pregnancies. However, Dr McLellan did not inform Mrs Montgomery of that risk. She also did not advise her of the alternative possibility of an elective caesarean section. Dr McLellan’s evidence was that she did not routinely warn diabetic women about shoulder dystocia because, in her view, if they were told about the risk, most would request a caesarean section. She considered the risk of serious injury resulting from shoulder dystocia to be small and believed that vaginal delivery remained appropriate.

Mrs Montgomery later gave birth vaginally at Bellshill Maternity Hospital on 1 October 1999. During labour, shoulder dystocia occurred. The baby was deprived of oxygen and was born with serious disabilities, including cerebral palsy. Mrs Montgomery brought proceedings against Lanarkshire Health Board, alleging negligence by Dr McLellan. The central complaint was not that the vaginal delivery had been performed incompetently, but that Mrs Montgomery had not been properly informed of the material risk of shoulder dystocia or the reasonable alternative of caesarean delivery. She argued that, had she been warned, she would have chosen a caesarean section and the injury would have been avoided. 

4. Legal Issues

The Supreme Court had to decide the following legal issues:

1. Was Dr McLellan under a legal duty to inform Mrs Montgomery of the risk of shoulder dystocia associated with vaginal delivery?
2. Should the standard for disclosure of medical risks be governed by responsible medical practice under Bolam and Sidaway, or by the patient’s right to make an informed decision?
3. Was the risk of shoulder dystocia a “material risk” that a reasonable person in Mrs Montgomery’s position would likely consider significant?
4. Was caesarean section a reasonable alternative treatment option that should have been discussed?
5. If Mrs Montgomery had been properly informed, would she probably have chosen a caesarean section, thereby establishing causation?

5. Parties’ Arguments

5.1 Appellant’s Arguments

Mrs Montgomery argued that Dr McLellan had breached her duty of care by failing to warn her of the risk of shoulder dystocia and by failing to discuss caesarean section as an alternative. She submitted that the risk was material because it was significantly higher in diabetic pregnancies and because its consequences could be grave. She relied on the principle that a competent adult patient had the right to decide what medical risks to accept. Her case was that medical judgment could not justify withholding information simply because the doctor thought disclosure might lead the patient to choose a different course.

She further argued that, had she been advised of the risk and the alternative, she would have requested a caesarean section. On this basis, the failure to warn caused the injury.

5.2 Respondent’s Arguments

Lanarkshire Health Board argued that Dr McLellan’s conduct was consistent with responsible medical practice. It relied on the traditional approach in Bolam and Sidaway, under which a doctor would not be negligent if acting in accordance with a responsible body of medical opinion. The Board contended that the risk of serious harm from shoulder dystocia was small, even though the risk of shoulder dystocia itself was higher in diabetic pregnancies. It argued that Dr McLellan had exercised professional clinical judgment in not advising Mrs Montgomery of a risk that might cause unnecessary anxiety.

The Board also disputed causation. It maintained that even if Mrs Montgomery had been warned, she would not necessarily have chosen a caesarean section. Therefore, the alleged breach did not legally cause the baby’s injuries.

6. Judgment and Ratio Decidendi

The Supreme Court unanimously allowed the appeal. It held that Dr McLellan was under a duty to take reasonable care to ensure that Mrs Montgomery was aware of the material risk of shoulder dystocia and of the reasonable alternative of caesarean section. The Court rejected the application of the Bolam test to the issue of advice and disclosure of risks. While Bolam remained relevant to diagnosis and treatment, it did not govern the patient’s entitlement to information needed for autonomous decision-making.

The Court found that the risk of shoulder dystocia was material. A reasonable person in Mrs Montgomery’s position would likely have attached significance to a 9–10% risk, especially given the possible severity of the consequences. The Court also accepted that caesarean section was a reasonable alternative. It held that, if properly advised, Mrs Montgomery would probably have chosen caesarean delivery. The appeal was therefore allowed and damages were awarded.

Ratio decidendi: A doctor is under a duty to take reasonable care to ensure that a patient is aware of any material risks involved in recommended treatment, and of any reasonable alternative or variant treatments. A risk is material if a reasonable person in the patient’s position would likely attach significance to it, or if the doctor knows or should reasonably know that the particular patient would likely attach significance to it.

The Court distinguished this binding principle from obiter observations about the broader culture of medical paternalism. Those observations explained the policy background but were not, by themselves, the legal rule required for the decision.

7. Critical Analysis

7.1 Significance of the Decision

The decision’s main contribution was its clear rejection of medical paternalism in consent law. Earlier authority, especially Sidaway v Board of Governors of the Bethlem Royal Hospital, had left disclosure heavily influenced by professional medical standards. Montgomery moved the law toward patient autonomy and dignity. It recognised that consent is not valid merely because a doctor acted according to medical custom. Consent requires meaningful participation by the patient.

The judgment also aligned law with modern ethical standards. The General Medical Council had already emphasised shared decision-making, and Montgomery brought legal doctrine closer to professional guidance. The GMC later described the decision as requiring a meaningful, clear conversation rather than simply overwhelming patients with information. 

7.2 Implications and Impact

The practical impact of Montgomery has been substantial. Doctors must now consider not only what the medical profession thinks should be disclosed, but what matters to the patient. Medical professionals must discuss material risks and reasonable alternatives, and clinical records must show that such discussions took place. The case affects all areas of healthcare, not only obstetrics.

The decision has also become central in clinical negligence litigation. Commentary five years after the judgment described it as the “first port of call” in claims concerning the adequacy of patient consent. Subsequent cases have applied and refined Montgomery, especially around what counts as a reasonable alternative treatment.

7.3 Critical Evaluation

The strength of the judgment lies in its principled foundation. The Court correctly treated patients as rights-bearing individuals rather than passive recipients of medical expertise. Its test of materiality is flexible because it combines an objective standard with sensitivity to the particular patient’s concerns.

However, the decision also creates practical difficulties. Doctors may struggle to know how much information is enough, especially where many risks are possible but unlikely. There is a danger that consent discussions become defensive and documentation heavy. The judgment insists that disclosure is not a mechanical list of risks, but in practice, clinicians may respond cautiously by giving excessive information.

A further criticism is that the judgment may understate the complexity of medical decision-making. Patients depend on professional interpretation of risk, and autonomy can be weakened rather than strengthened if information is presented without context. Nevertheless, these problems are not fatal to the reasoning. They show that Montgomery requires careful communication, not merely more disclosure.

8. Conclusion

Montgomery v Lanarkshire Health Board fundamentally reshaped the law of informed consent. The Supreme Court held that doctors must disclose material risks and reasonable alternatives so that patients can make informed choices about their own bodies and medical treatment. The key takeaway is that consent is judged from the standpoint of the patient, not solely by reference to accepted medical practice.

The judgment will be remembered for replacing a paternalistic model of medical advice with a patient-centred standard based on autonomy. Its continuing importance lies in its practical effect on healthcare communication, clinical negligence litigation, and professional medical standards. Future disputes are likely to focus on the boundaries of “material risk” and “reasonable alternative treatment,” but the central principle is now clear: patients must be treated as decision-makers, not merely as recipients of care.

Bibliography

Cases

Bolam v Friern Hospital Management Committee [1957] 1 WLR 582.

Canterbury v Spence 464 F 2d 772 (DC Cir 1972).

Chester v Afshar [2004] UKHL 41, [2005] 1 AC 134.

Montgomery v Lanarkshire Health Board [2015] UKSC 11, [2015] AC 1430.

Rogers v Whitaker (1992) 175 CLR 479 (HCA).

Sidaway v Board of Governors of the Bethlem Royal Hospital [1985] AC 871.

Legislation

Human Rights Act 1998.

Secondary Sources

Emily Jackson, Medical Law: Text, Cases, and Materials (5th edn, OUP 2019).

Jonathan Herring, Medical Law and Ethics (9th edn, OUP 2023).

Alastair Mullis and Ken Oliphant (eds), Tort Law: Text and Materials (6th edn, OUP 2021).

Margaret Brazier and Emma Cave, Medicine, Patients and the Law (7th edn, MUP 2023).

Sidney W DeLong, ‘The Disclosure Debate and Patient Autonomy in Medical Negligence’ (2016) 79 Modern Law Review 104.

General Medical Council, Consent: Patients and Doctors Making Decisions Together (GMC 2008).

General Medical Council, ‘Montgomery and Informed Consent’ (GMC, 2020) https://www.gmc-uk.org/professional-standards/learning-materials/blog—montgomery–judgement accessed 25 May 2026.

Supreme Court, ‘Montgomery v Lanarkshire Health Board [2015] UKSC 11’ https://www.supremecourt.uk/cases/uksc-2013-0136 accessed 25 May 2026.