Informed Consent: Who knows what’s best?

26/01/2026

By Kriti Upadhyay and Sophie Holme

Earlier in 2025, the British Medical Association published an updated Ethics Toolkit, titled “Consent and refusal by adults with decision-making capacity.”¹
This toolkit provides comprehensive practical guidance to clinicians across the UK about the process of obtaining consent from adult patients, and is intended to apply any time the doctor wishes to initiate any examination, treatment or intervention. The guidance also covers situations such as sharing information with patients, consent in emergency situations and consent for medical research.
This article considers the BMA toolkit in the context of the current case law on consent, particularly following the Supreme Court decision in McCulloch v Forth Valley Health Board [2023] UKSC 26.

The law on materiality: from Montgomery to McCulloch

It is necessary, before turning to the BMA Toolkit, to first consider the current state of the law on informed consent, and three key decisions from the last decade: Montgomery, Duce and McCulloch.
Readers will be very familiar by now with the Supreme Court’s decision in Montgomery v Lanarkshire Health Board [2015] UKSC 11, which put forward the correct approach for clinicians to adopt when consenting a patient for treatment, including the discussion of risks and alternative treatment options.

The Supreme Court considered the history of the law in respect of consent and breach of duty, including the application of Bolam v Friern Hospital Management
Committee [1957] 1 WLR 582 (‘the Bolam test’) and the approach endorsed in Sidaway v Board of Governors of the Bethlem Royal Hospital and the Maudsley Hospital [1985], to determine whether a doctor’s failure to warn a patient of the risks of treatment was a breach of her duty of care, and was normally to be determined by the application of the Bolam test.

In Montgomery, the Supreme Court noted that the reality of the doctor-patient relationship implicit in the time of decisions such as Sidaway has shifted. The court considered in detail the more recent clinical guidance, including the GMC’s ‘Good Medical Practice’ and guidance on consent, which focused (by the date of the judgment) on a “basic model of partnership between doctor and patient” ², as opposed to the more paternalistic relationship of old. Lord Kerr and Lord Reed pointed out that the GMC advised that clinicians must tell patients if treatment might result in a serious adverse outcome, even if the risk in question was objectively very small, and that patients should be told about less serious complications if they occur very frequently.

Considering the social and legal developments that have taken place since the earlier decisions, including developments in human rights law, the Supreme Court unanimously held that there is a duty on the part of doctors to take reasonable care to ensure that a patient is aware of material risks of injury that are inherent in treatment:

“This can be understood, within the traditional framework of negligence, as a duty of care to avoid
exposing a person to the risk injury which she would otherwise have avoided, but it is also the counterpart of the patient’s entitlement to decide whether or not to incur that risk.”³

The court drew a distinction between on the one hand, the doctor’s role in considering the possible investigatory or treatment options which should be offered to the patient, and which are an exercise of professional skill and judgment on the part of the clinician, and on the other hand, the doctor’s role in discussing with the patient any recommended treatment and the possible alternatives as well as the risks of injury which may be involved. The court rejected the suggestion that the latter role is solely a matter of the exercise of medical skill, ignoring entirely the patient’s right to decide the risks to her health that she is willing to run, which is a decision that could be influenced by non-medical considerations.

The fundamental principle endorsed by the court in Montgomery was that an adult of sound mind is entitled to decide which, if any, 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’ was defined as “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.”⁴

The next key decision when considering the case law on informed consent is Duce v Worcestershire Acute Hospitals NHS Trust [2018] EWCA Civ 1307. Mrs Duce brought a claim for damages following a total abdominal hysterectomy and bilateral salpingo-oophorectomy, which left her with nerve damage and serious and permanent chronic post-surgical pain (‘CPSP’). The Court of Appeal considered the claimant/appellant’s case that she was not adequately warned of the risk of pain in relation to the procedure when she was consented for it.

At trial, the judge had considered the decision in Montgomery, and the test of materiality, but found in respect of breach of duty that the claimant had been well aware of the alternative treatment on offer; that as both sides’ expert gynaecologists agreed, there was no duty to warn her of the risk of developing CPSP in particular; that at the relevant time, in 2008, there was in fact no duty to warn a patient such as the claimant of the risk of developing either short term or long term chronic or neuropathic pain; and that the claimant understood, at the point where she was asked to consent to the procedure, that the operation would cause her some pain, and was specifically warned of the risk of 3–6 months of numbness or pain.

In respect of causation, the trial judge considered the history of the claimant’s condition, and the attempts by clinicians to steer her towards other treatment options prior to this procedure and rejected the case put forward On her behalf it was argued that if she had been warned of a risk of chronic pain or ‘nerve pain’, she would either have decided not to have the operation, had second thoughts, sought a second opinion, or at least put things off. The judge concluded that it was more likely than not that she would have proceeded to the operation on the day.

In their judgment on appeal, the Court of Appeal considered the application of Montgomery in respect of breach of duty to the claim, as well as the relevant principles on causation, including the test of causation set out in Chester v Afshar [2004] UKHL 41.

The appeal failed, with the court considering that the judge was correct to find that in 2008 there was insufficient understanding among gynaecologists of the existence of a risk of ‘chronic pain, or of neuropathic (or nerve) pain, whether that was long term or short term’, to justify the imposition of a duty to warn of such a risk. This was held to be consistent with the Montgomery approach, because “a clinician is not required to warn of a risk of which he cannot reasonably be taken to be aware.”⁵ The question of materiality therefore only arises if the risk was one which was known.

The Court of Appeal interpreted Montgomery as creating a twofold test⁶:

1. What risks were or should have been known to the medical professional: this is a question for the experts;
2. Whether the patient should have been told about such risks by reference to whether they were ‘material’. This is a question for the court to determine, and not the subject of the Bolam test.

The court also rejected the claimant’s arguments in respect of causation. It was argued on behalf of the claimant that Chester created essentially an ‘alternative pathway to causation in consent cases,’ subject to three requirements, which were said to be satisfied in the present case: (i) the injury was intimately involved with the duty to warn; (ii) the duty was owed by the doctor who performed the surgery to which the patient had consented; and (iii) the injury was the product of the very risk that the patient should have been warned about when they gave their consent.

The Court of Appeal did not agree that Chester amounted to a departure from ‘but for’ causation, emphasising instead from that decision the need for proof that (i) there was a failure to warn of the relevant risk which did arise; and (ii) as a matter of fact, if the claimant had known of The actual risks of the proposed surgery, she would not have consented to the procedure on the relevant date. The approach in Chester was said to be a modification to the normal approach to causation, rather than a ‘free‑standing test’.⁷

The Supreme Court then had reason to revisit the issue of consent more recently in McCulloch v Forth Valley Health Board [2023] UKSC 26. In this appeal, the court considered what legal test should be applied to the assessment as to whether an alternative treatment is reasonable and requires discussing with the patient. Where a doctor fails to make a patient aware of an alternative treatment, in a situation where the doctor’s opinion is that the alternative treatment is not reasonable, and that opinion is supported by a responsible body of medical opinion, does that fall below the required standard of reasonable care? ⁸

Applying the principles set out in both Montgomery and Duce, the court emphasised that the identification of which treatments are reasonable alternatives, i.e. clinically appropriate, is as much a matter falling within medical expertise and professional judgment, and hence governed by the Bolam test, as the identification of risks associated with any treatment. The court noted that both are closely linked, and the risk of any given treatment will be a significant part of any analysis of alternative treatment options ⁹. Once reasonable alternative treatment options have been identified, the doctor is required at the second stage to inform the patient of the reasonable alternative treatments (which have been identified by the professional as clinically appropriate), and of the material risks of those alternative treatments.

The court was at pains to stress that “it is not being suggested that the doctor can simply inform the patient about the treatment option or options that the doctor himself or herself prefers. Rather the doctor’s duty of care, in line with Montgomery, is to inform the patient of all reasonable treatment options applying the professional practice test.” ¹⁰

The Supreme Court considered that this approach would be consistent with both Montgomery and Duce, and rejected the appellant’s submissions that the duty to take reasonable care to ensure that the patient is aware of ‘any reasonable alternative or variant treatments’ means all such treatments, or that what constitutes a reasonable alternative treatment is to be determined by the court, “unshackled from the professional practice test.” ¹¹

Both the BMA and the General Medical Council intervened in the appeal, emphasising the importance of clinical judgment in determining reasonable alternative treatment options. The BMA further pointed out, and the court accepted that, the doctor’s duty is not fulfilled by ‘bombarding’ the patient with every possible treatment option for every potential diagnosis, potentially ‘obstructing’ patient understanding ¹².

The Supreme Court also considered that rejecting the Bolam/professional practice test in determining reasonable alternative treatments might lead to an unfortunate conflict in the exercise of a doctor’s role, where the law might require a doctor to inform a patient about an alternative medical treatment which the doctor exercising his professional skill and judgment, and supported by a responsible body of medical opinion, would not consider to be a reasonable medical option ¹³.

Practical guidance: the BMA Toolkit

The 2025 BMA Toolkit on consent sits alongside the GMC’s ‘Decision making and consent’ professional standard ¹⁴, but helpfully incorporates the key guidance from the GMC. At twenty-one pages long, it is a comprehensive document.

The toolkit emphasises that doctors can apply their own professional judgement about the most appropriate way to seek consent, which will be dependent upon the specific circumstances of each decision, including:

• a. the nature and severity of the patient’s condition and how quickly the decision must be made;
• b. the complexity of the decision, the number of available options and the level of risk or degree of uncertainty associated with any of them;
• c. the impact of the potential outcome on the patient’s individual circumstances;
• d. what the clinician already knows about the patient, and what the patient already knows about their condition, the potential options for treating or managing it;
• e. and the nature of the consultation.

While consent does not always need to be in writing, the patient’s records should ‘usually’ include discussions about the treatment options, including potential harms and benefits of any treatment, any specific concerns the patient had and any other information that was given to them. Doctors are reminded that consent should be a continuing process rather than a one‑off decision, giving patients continuing opportunities to ask further questions and to review their decisions.

If a patient asks for treatment that the clinician does not think would be clinically appropriate for them, their reasons for requesting it should be discussed with them. “Any significant factors for the patient should be explored further, including non‑clinical factors such as their beliefs or views. Following this, if you still consider that the treatment is not clinically appropriate, you do not have to provide it.” However, the reasons for the refusal should still be explained clearly to the patient, as well as other options available to them including seeking a second opinion.

The toolkit also sets out a very comprehensive list of matters that the doctor should provide them with ‘sufficient, clear and accurate information’ about, in respect of any proposed course of action or treatment. This includes the purpose of the investigation or treatment, details and uncertainties of the diagnosis, options for treatment, including the option of no treatment, the likely benefits and probabilities of success of each option, the risks and potential side effects or adverse outcomes, the name of the doctor with overall responsibility for their care, and their reasons for any recommended treatment options.

The discussions should be tailored according to the nature and complexity of the proposed course of action, the level of risk associated with it, and the individual’s own concerns, wishes, values, and their understanding of their condition and prognosis.

Information should only be withheld from the patient in the very limited scenario where the doctor has a reasonable belief that providing the information would cause the patient serious harm, but the exception should not be abused.

Doctors should take all reasonable steps to maximise the patient’s ability to understand, consider options and make a decision. This includes steps such as taking time to understand the patient’s values, wishes, preferences and knowledge of their own condition, using clear and consistent language when discussing risks of harm and potential benefits, encouraging patients to ask questions, supporting patients with additional needs to have the time and any reasonable adjustments they need, giving the patient time to reflect, before and after they make a decision, providing the opportunity for patients to discuss their options with others, and considering whether the patient might need more time with the doctor or others in the healthcare team.

Essentially, the main takeaway from the toolkit is that one size does not fit all when it comes to the process of obtaining consent from a patient for a particular treatment/procedure, or indeed when discussing the available options with the patient before a particular option is ultimately consented to. The toolkit attempts to put forward a series of comprehensive guidelines to assist clinicians with the process, in a way that reduces the risk of paternalism and promotes greater equality within the doctor-patient relationship.

From the patient’s perspective, however, one might be concerned that there is no particular hierarchy of factors: it would appear to be for the clinician to determine which factors they prioritise above the others. One clinician, when considering the specific circumstances for a particular decision to be made, might prioritise the severity of the patient’s condition and the need for urgent treatment, while another might be more persuaded by the patient’s concern that they cannot afford a lengthy recovery period. In practice, even the same treatment options might be presented to the patient in a very different way, depending upon what each clinician chooses to prioritise.

The other practical difficulty with the toolkit is the fact that all of these discussions realistically require sufficient time, if the doctor is to genuinely comply with the guidance. That may be more available in the hospital context, particularly for non-urgent surgical procedures where there is a consent form to be signed, and/or long courses of treatment where a patient might be seen by the same consultant on an ongoing basis. Unfortunately, a busy locum NHS GP, seeing a patient in a 5–10 minute appointment, is likely to have limited opportunity to properly get to the know the patient, or to be able to give them enough time to ask questions or reflect.

It might be suggested that the ‘nature and complexity’ of GP consultations is not on the same level as a surgeon discussing proposed surgical procedures with a patient, so the lack of time is less significant in that context. However, given that GPs are often managing and treating a range of conditions within the community, and that for many patients, the majority of their clinical interactions will be with their GP, the importance of an effective and inclusive consent process even within the busy and time-limited general practice consultation should not be underestimated.

Similar concerns may well apply to other clinician interactions where consent needs to be obtained from a patient under some time pressure, such as in the middle of labour: to what extent is the need for a swift decision to be made going to be allowed to override many of the more patient-centred aspects of the guidance?

Overall, while the toolkit is to be commended for its comprehensive and detailed guidance that appears to cover all the key points arising from recent case law, it remains to be seen how effectively in practice the already overstretched clinicians in many parts of the NHS are going to be able to apply its principles.

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1. https://www.bma.org.uk/media/txrnpo3s/consent-and-refusal-by-adults-with-decision-making-capacity-guidance-updated-2025.pdf ↩︎
2. Montgomery, per Lord Kerr and Lord Reed at [78] ↩︎
3. Ibid, at [82] ↩︎
4. Ibid, at [87] ↩︎
5. Duce v Worcestershire Acute Hospitals NHS Trust [2018] EWCA Civ
   1307, per Lord Justice Hamblin at [43] ↩︎
6. Ibid, at [33] ↩︎
7. Ibid, at [51]-[66] ↩︎
8. McCulloch v Forth Valley Health Board [2023] UKSC 26, per Lord
   Hamblen and Lord Burrows at [3] ↩︎
9. Ibid, at [64] ↩︎
10. Ibid, at [58] ↩︎
11. Ibid, at [60] ↩︎
12. Ibid, at [73] ↩︎
13. Ibid, at [71] ↩︎
14. https://www.gmc-uk.org/-/media/documents/gmc-guidance-for-doctors—decision-making-and-consent-english_pdf-84191055.pdf ↩︎