The Trojan Horse of Therapeutic Privilege in Hii Chii Kok

By Naomi Koh Jie Min


The 2017 Court of Appeal case Hii Chii Kok v Ooi Peng Jin London Lucien1 [Hii Chii Kok] has been heralded as “[t]he end of the ‘doctors know best’ era” by commentators.2 In a landmark decision, a Coram of five Judges unanimously rejected the unapologetically paternalistic Bolam-Bolitho3 test for negligent advice in favour of a three-stage test based on the UK Supreme Court’s 2015 decision in Montgomery v Lanarkshire Health Board4 [Montgomery]. As the Court put it, a “seismic shift in medical ethics, and in societal attitudes towards the practice of medicine” necessitated an approach that balances beneficence with patient autonomy.5 Hii Chii Kok is indisputably a welcome addition to local case law on medical negligence, but it should not be welcomed uncritically. A key issue with Hii Chii Kok lies in the unclear scope of the defence of therapeutic privilege6 to a claim of negligent advice. In fairness to the Court of Appeal, the doctrine of therapeutic privilege, as Mulheron observes, “has suffered from an almost complete lack of judicial delineation in English law”7 and by extension, Singapore law. However, the cost of leaving therapeutic privilege undefined is high; it leaves the Hii Chii Kok test open to abuse.


A. Singapore: Gunapathy

To understand Hii Chii Kok, one must consider the state of the law that preceded it. Locally, Khoo James v Gunapathy d/o Muniandy8 [Gunapathy] stood for the position that a two-stage inquiry was required to determine whether a professional had breached his duty of care: namely, whether the expert (1) directed his/her mind to the comparative risks and benefits, and (2) reached a “defensible conclusion”9 after balancing risks and benefits. In other words, the Court of Appeal had adopted the Bolam test of the ordinary skilled man exercising and professing to have a skill,10 with the Bolitho addendum that the conclusion reached must have a logical basis.11 Further, and more pertinently, the Court accepted that the Bolam-Bolitho test applied to pre-treatment advice, following the House of Lords in Sidaway v Bethlem Royal Hospital12 [Sidaway].

B. UK: Sidaway Overuled in Montgomery

Montgomery amended the standard for risk disclosure to one where the doctor is:

“[U]nder 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.”13

In this decision, the House of Lords effectively overruled the test in Sidaway. Although, as Hobson observes, their Lordships tried to “frame Montgomery as a development of Sidaway ... to show that the development from Sidaway to Montgomery is smooth”,14 in principle Montgomery effectively displaces the concerns and policies that undergirded Sidaway’s stance that Bolam-Bolitho applied to medical advice.


In Hii Chii Kok, the Court acknowledged the increasing recognition of patient autonomy across common law jurisdictions.15 More specifically, the scope of patient autonomy is greater in relation to medical advice, which guides patients to make an active choice.16 Hence, the Bolam-Bolitho test was no longer applicable in relation to advice. Rather, the Court endorsed a three-stage test (referred to as the “Hii Chii Kok test”).

In the first stage of the Hii Chii Kok test, the Court answers the question of what information the doctor has a duty to disclose. This comprises of what a reasonable person in the patient’s position would wish to know, as well as information that the doctor knows or ought to have known would be important to the particular patient in question.17 The first stage therefore effectively echoes Montgomery.

At the second stage, the Court evaluates whether the doctor was in possession of the pertinent information. If answered in the negative, the Court then has to assess whether the doctor’s ignorance arose from negligence in diagnosis and treatment. This inquiry would fall under the ambit of the Bolam-Bolitho18 test.

If the second stage is answered in the affirmative, then the final question is whether the doctor’s withholding of information was justified. The Court declined to limit the scope of potential justifications, but identified emergencies, waivers, and therapeutic privilege as specific instances in which a doctor may withhold information from a patient.19 It is the exception for therapeutic privilege that is contentious as further explored below.


A. The Exception

Although Hii Chii Kok purports to eschew the Bolam-Bolitho test in favour of a more expansive paradigm with greater room for patient autonomy, questions have been raised as to the efficacy of the revised test in promulgating these goals. While the Hii Chii Kok test is a step forward with a more patient-focused approach, the wide yet murky scope of the therapeutic privilege exception creates a very real concern. If not properly defined, this exception leaves an opening for medical paternalism to reassert itself. As discussed below, doctors could infringe on a patient’s right to make an informed decision under the guise of the patient’s supposed inability to do so.

What do we know about the therapeutic privilege exception? The Court of Appeal has suggested that it applies exclusively in “exceptional circumstances”,20 but has been vague on the precise details of the test. Ostensibly, it is an objective factual inquiry21 as to whether the patient is likely to be harmed disproportionally to the impact of being provided with the information in question. Showing advertence to the reality that the therapeutic privilege exception is prone to abuse, the Court explicitly stated that the exception should not preclude patients from making a choice merely because the patient’s decision appears contrary to their interests.22 However, and albeit discrepantly, patients who may choose not to undergo “relatively safe treatments that [could] drastically improve their quality of life” may be caught under the exception.23 Moreover, patients who possess mental capacity but also have impaired decision-making abilities are caught under this exception.24

The Court’s attempt to delineate the boundaries of therapeutic privilege is unsatisfying. For one, must the “serious physical or mental harm”25 be medically recognised? Further, would “physical or mental harm” capture scenarios where the anticipated harm arises from the patient’s anticipated refusal to undergo treatment? Given the Court of Appeal’s observation that therapeutic privilege would include “certain geriatric patients who … may be ‘easily frightened out of having even relatively safe treatments that can drastically improve their quality of life’”,26 this appears to be the case. However, this statement is problematic, especially in light of the potentially conflicting Mental Capacity Act27 [MCA] as discussed below.

The confusion that the therapeutic privilege exception generates is exacerbated by the reality that the three stages of diagnosis, advice, and treatment are not mutually exclusive. As the Court itself in Hii Chii Kok noted, “a single step in the medical care process will engage more than one aspect of the doctor’s duty, and the different aspects will then be in play concurrently”28. This permeability between stages is an issue given that it affects the test to be applied and consequently whether the therapeutic privilege exception would even come in play.

This problem was made apparent in Noor Azlin Bte Abdul Rahman v Changi General Hospital Pte Ltd29 [Noor Azlin]. In that case, one of the issues in dispute was whether the alleged negligence fell under the scope of diagnosis and treatment, or advice. The plaintiff argued that the defendants failed to advise her of the risk of cancer, such that she was unaware that other diagnostic options existed and did not make any further investigations. Nonetheless, the High Court found for the defendant. The lack of such advice stemmed from the defendants’ professional diagnosis that cancer was not a likely cause of the plaintiff’s complaints. Hence, the proper test to be applied was the Bolam-Bolitho test. Although the decision in Noor Azlin is not in itself controversial, the lack of a clear directive on how the stages are to be distinguished is troubling.

B. Therapeutic Privilege and the Mental Capacity Act

The MCA was enacted to regulate the decision-making process on behalf of those who lack capacity and hence are unable to make decisions for themselves. At first blush, the Hii Chii Kok test has no ostensible relation to the MCA; the former addresses the question of whether the patient’s consent was informed, while the latter deals with treatment in a situation where the patient is incapable of consenting.

However, it is unclear whether a doctor may evade liability for non-disclosure under the MCA in specific situations. More specifically, in light of the undefined boundaries of the therapeutic privilege exception, the implications of the MCA on the Hii Chii Kok test should be explored given that both fundamentally affect whether the principle of patient autonomy can be overridden by the patient’s lack of decision-making capacity. Under the Hii Chii Kok test, therapeutic privilege is explicitly raised as a defence to a charge of negligent advice where “beneficence comes to the fore”,30 echoing the MCA requirement that the decision be made in the “best interests”31 of the incapacitated individual.

Under s 7(2) of the MCA,32 a defendant doctor would not incur liability for an act done in connection with the care and treatment of the plaintiff, assuming that his or her act would not have attracted liability if the plaintiff hypothetically could and did consent. The defendant medical professional must take reasonable steps to establish whether the plaintiff lacks capacity. In addition, he or she must have reasonably believed that the plaintiff lacks capacity, and that it is in the plaintiff’s best interests that the act be done.33 It is conceivable that the “act” in this situation would extend to non-disclosure on the basis of therapeutic privilege. Which acts, therefore, would fall under the ambit of the MCA, and which would fall under the ambit of the Hii Chii Kok test?

The distinction between the two appears to be one of degree. For the therapeutic privilege exception, the Court suggested that it “should extend to cases where although patients have mental capacity, their decision-making capabilities are impaired to an appreciable degree34 [emphasis added]. In contrast, the MCA arguably requires total incomprehension35 or total inability36 to use or weigh information in the process of decision-making. Ultimately, however, the outcome regardless of which is applied is the same: both act to relieve the defendant of tortious liability.

Crucially, however, the MCA explicitly provides that a person is not to be treated as unable to make a decision merely because said decision is unwise.37 This point has been made earlier by Low, who argues that an “informed decision is not synonymous with [a] good decision”.38 This stands in stark contrast to the principle of patient autonomy apparently espoused by Hii Chii Kok – namely, that a doctor may justify omissions on the basis that he or she believed that the patient would be “frightened out of having even relatively safe treatments that can drastically improve their quality of life”.39

Clearly, a successful finding that the patient was fully incapacitated under the MCA is significantly more onerous than the finding that the patient was of a class to trigger the therapeutic privilege exception under Hii Chii Kok. Consequently, it should stand to reason that the corresponding boundaries of the test in Hii Chii Kok should be narrower. Since both exculpate a doctor facing a charge of negligence, it would be logically inconsistent to allow a doctor to prove less under the Hii Chii Kok test.


Ultimately, the therapeutic privilege exception as it stands is problematic because it is unclear. While it is meant to relate to “exceptional”40 situations, Hii Chii Kok does not provide a workable litmus test for when a situation would fall within its boundaries. Rather, Hii Chii Kok appears to take an expansive view of therapeutic privilege – perhaps more so than other jurisdictions. Pertinently, the House of Lords in Montgomery expressly rejected41 the defendant doctor’s argument in that case that it was “not in the maternal interests for women to have caesarean sections”42.

Granted, it is within the bounds of plausibility that a patient could be clearly and utterly incapable of making the required decision, but not trigger the provisions of the MCA. There reasonably is a space for the therapeutic privilege exception – but the current boundaries of the test are too wide. With respect, further clarification is essential.

In fairness to the Singapore Court of Appeal, the problems surrounding the doctrine of therapeutic privilege apply across jurisdictions. As Mulheron establishes, “the reality is that there is one clear instance of therapeutic privilege in English law”, and this rarity of application hampers the creation of a coherent, articulate doctrine.43

However, this rarity does not justify the continuing confusion surrounding therapeutic privilege. Locally, about 10% of the population suffers from anxiety and depressive disorders.44 This segment – along with the overly anxious, the hesitant to undergo medical procedures, and perhaps even the simply cautious – risk being caught unnecessarily by too expansive a doctrine. Ultimately, for Hii Chii Kok to truly represent a shift in medical ethics towards upholding the principle of patient autonomy, the therapeutic privilege doctrine must be re-considered.

[1] [2017] SGCA 38; [2017] 2 SLR 492.

[2] Hairul Hakkim and Kevin Ho Hin Tat, “The end of the ‘doctors know best’ era – from medical paternalism to patient autonomy”, Singapore Law Blog, (16 July 2017) online: <> accessed 10 June 2018.

[3] Supra note 1.

[4] [2015] UKSC 11; [2015] AC 1430.

[5] Ibid at [120].

[6] Also termed “doctor’s privilege” or “therapeutic exception” in some cases.

[7] Rachael Mulheron, “Has Montgomery Administered the Last Rites to Therapeutic Privilege? A Diagnosis and a Prognosis” (2017) 70:1 Current Leg Probs at 149.

[8] [2002] SGCA 25; [2002] 1 SLR(R) 1024.

[9] Defensible is not to be equated with reasonable. See Gunapathy, ibid at [65].

[10] Specifically, “[a doctor] is not guilty of negligence if he has acted in accordance with a practice accepted as proper by a responsible body of medical men skilled in that particular art” [emphasis added]: Bolam v Friern Hospital Management Committee [1957] 1 WLR 582 at 587.

[11] Yeo Peng Hock Henry v Pai Lily [2001] SGCA 72; [2001] 3 SLR(R) 555 at [16], as affirmed in Gunapathy at [52], [61].

[12] [1985] AC 871 (HL).

[13] Supra note 4 at [87].

[14] Clark Hobson, “No (,) More Bolam Please: *Montgomery v Lanarkshire Health Board*” (2016) 79(3) MLR 468.

[15] Supra note 1 at [116].

[16] Ibid at [93].

[17] Ibid at [137], [138].

[18] Ibid at [133], [147].

[19] Ibid at [134], [149] and [151].

[20] Supra note 1 at [153].

[21] Ibid.

[22] Ibid.

[23] Ibid at [152].

[24] Ibid at [153].

[25] Ibid at [152].

[26] Ibid.

[27] Cap 177A, 2010 Rev Ed Sing.

[28] Supra note 1 at [90].

[29] [2018] SGHC 35.

[30] Supra note 1 at [149].

[31] Supra note 28, s 6(10).

[32] Ibid, s 7(2).

[33] Ibid, s 7(1).

[34] Supra note 1 at [152].

[35] Supra note 28, s 5(1)(a).

[36] Ibid, s 5(1)(c).

[37] Ibid, s 3(4).

[38] Kee Yang Low, “Doctor’s duty of disclosure and the Singapore Court of Appeal decision in Hii Chii Kok: Montgomery transformed” [2017] 25:2 Tort L Rev 79 at 89.

[39] Supra note 1 at [152].

[40] Ibid at [153].

[41] Supra note 4 at [91].

[42] Ibid at [13].

[43] Supra note 7, at 186.

[44] Jaclyn Lim, “Anxiety in Singapore: Stats, Types and Who’s at Risk”, (blog), online: <> accessed 12 July 2018.