ANGELA CHEN v. WAI WAI CHEN

HCAP 10/2020

[2026] HKCFI 1269

IN THE HIGH COURT OF THE

HONG KONG SPECIAL ADMINISTRATIVE REGION

COURT OF FIRST INSTANCE

PROBATE ACTION NO 10 OF 2020

________________________

________________________

BETWEEN

________________________

________________________

D E C I S I O N

________________________

INTRODUCTION

1.  This probate action concerns the estate of the late Madam Yang Foo-Oi. The plaintiff and the defendant are her two daughters. There have been a number of interlocutory applications taken out since the action was commenced in 2020. As in the previous decisions, I shall call the parties by their first names, Angela (the plaintiff) and Vivien (the defendant), and the deceased “Mother”. I shall call the late Dr Chen Din Hwa, the father of Angela and Vivien, “Father” below. Dr Chen was the founder of the Nan Fung group. He and Mother were married until their divorce in 2011.

2.  In this action, Angela seeks to propound the will executed by Mother on 15 February 2008 (“the 2008 will”) which left all her assets to Angela and appointed her as the sole executrix.

3.  Vivien, on the other hand, seeks to propound an earlier will made by Mother dated 27 October 2004 (“the 2004 will”) under which there would be an equal division of assets between the two daughters, and Vivien would be appointed as a co-executrix.

4.  For the background of the action and a broad overview of the parties’ pleaded cases, see, eg, the decision of Wilson Chan J at [2024] HKCFI 962, paras 7 to 24.

5.  This is the decision on the summons dated 31 March 2025 taken out by Vivien to strike out various paragraphs in the three reports made by Angela’s psychiatric experts. The reports are all dated 24 March 2025. The three experts are:

(1) Dr Wong Chung Kwong (“Dr CK Wong”);

(2) Dr Cheung Kin Leung Ben (“Dr Ben Cheung”); and

(3) Dr Wong Yee Him John (“Dr John Wong”).

6.  I shall refer to the above three reports collectively as “the Reports” below.

7.  In my view, the application turns on a proper interpretation of the following:

(1) the order made by Wilson Chan J on 16 July 2024 (as subsequently re-amended) in which leave was granted to parties to adduce psychiatric expert evidence (“the Order”); and

(2) the report of Dr Pramod Prabhakaran, Vivien’s psychiatric expert, dated 27 January 2025.

THE ORDER AND THE EXPERT REPORTS

8.  The Order was made upon a summons taken out by Angela dated 8 April 2024 and a summons taken out by Vivien dated 22 April 2024.

(1) In Angela’s summons, she sought expert directions in respect of Mother’s testamentary capacity.

(2) In Vivien’s summons, in addition to the above issue, she also sought expert directions on Mother’s susceptibility to undue influence or fraud by reason of her medical condition as pleaded by Vivien.

9.  After a contested hearing, the Order was made. I highlight the following directions.

10.  Leave was granted to parties to adduce psychiatric expert evidence on two issues: (1) Mother’s testamentary capacity, and (2) Mother’s susceptibility to probate undue influence by reason of her medical condition as pleaded in para 47 of Vivien’s re-amended defence and counterclaim: para 1 of the Order. I shall refer to the two issues as “the first issue” and “the second issue”, respectively, below.

11.  On the first issue, leave was granted to Angela to rely on 16 historical reports made variously by Dr Ben Cheung, Dr CK Wong and Dr John Wong during the period between October 2007 to May 2014. I should point out at the outset that Dr Ben Cheung was the psychiatrist who examined Mother before she executed the 2008 will and the will was executed in his presence. His report in respect of that examination is one of the 16 historical reports. Vivien was granted leave to adduce evidence from her own psychiatric experts. See paras 1 to 3 of the Order. What should be highlighted here is that no leave was granted to Angela to file any reply evidence in respect of the first issue after Vivien filed her report.

12.  On the second issue, Angela was granted leave to rely on the same 16 historical reports: paras 1 and 2 of the Order. Vivien was granted leave to adduce evidence from her own psychiatric experts: para 3 of the Order. As for Angela, there was a further leave granted in para 6, which is the presently material paragraph. It provided:

“Leave be granted to the Plaintiff to adduce additional expert evidence on the 2^nd Expert Issue (if so advised) from P’s Experts and to file and serve the report(s) in relation thereto within 35 days from the service of D’s Expert Reports, and to adduce such reports as expert evidence at trial (“P’s Additional Expert Report(s)”)” (underline added)

13.  What should be highlighted here is that, first, no leave was granted to Angela to file further reports in addition to the 16 historical reports before Vivien is to file hers; and, second, the evidence to be filed subsequently by Angela was described as “additional” evidence. Mr Benjamin Yu, SC, appearing with Mr Bernard Man, SC, Mr Keith Lam and Mr Danny Tang for Angela, submits that, by reason of such description, para 6 grants leave to Angela to adduce expert evidence generally on the second issue, as opposed to only evidence in response to Vivien’s expert evidence. I shall return to this submission below.

14.  The rest of the Order contained standard provisions covering the holding of a without prejudice meeting between the experts, the filing of a joint statement, and the signing of experts’ declarations: see paras 7 to 9.

15.  Pursuant to the Order, Vivien filed Dr Prabhakaran’s report which covers both the first and second issues. Angela then filed the Reports.

VIVIEN’S APPLICATION

16.  In her striking out summons, Vivien asks the court to expunge the following sections or paragraphs from the Reports:

(1) in Dr CK Wong’s report:

(i) the words “and Delusions” in para 36;

(ii) paras 161 to 213;

(iii) para 215; and

(iv) the words “and Delusions” in para 217;

(2) in Dr Ben Cheung’s report:

(i) Section A;

(ii) Section B;

(iii) Section E;

(iv) Section F; and

(v) para 87; and

(3) in Dr John Wong’s report:

(i) Section A; and

(ii) Section D5.

17.  Vivien puts forward two grounds.

18.  First, the matters covered in the above paragraphs concern the first issue (testamentary capacity), but not the second issue (Mother’s susceptibility to probate undue influence). In the Order, no leave was granted to Angela to file further evidence on the first issue. And para 6 of the Order allowed her to file additional reports on the second issue only. These paragraphs were therefore included without leave and should be expunged.

19.  The second ground applies to paras 185 to 196 in Dr CK Wong’s report. There, he gave opinion on the issue of when Father began to lose his mental capacity. Vivien’s position is that this is a novel expert issue, for which no leave was granted in the Order. Hence, independently of the first ground, those paragraphs should also be expunged for this reason.

DR PRABHAKARAN’S REPORT

20.  Dr Prabhakaran’s report is 53 pages long (not counting appendices). It is divided into Sections A to K.

21.  In para 2 of Section A, Dr Prabhakaran states his conclusion on the first issue:

“Based on my examination of the documents provided in this matter, in my clinical opinion and on the balance of probability, Mother, when she executed her Will on 15 February 2008, had a disorder of the mind within the terms of the Banks v Goodfellow judgement, namely vascular mild cognitive impairment and depression. This may well have affected her capacity to fully appreciate the consequences of her testamentary decisions. There is the possibility that Mother held irrational beliefs or insane delusions about her daughter, Vivien, which could have poisoned her affections towards her, and caused her to alter her testamentary deposition.”

22.  In para 3 of the same section, Dr Prabhakaran states his conclusion on the second issue:

“In my clinical opinion, and on the balance of probability, Mother would be considered vulnerable to undue influence due to her complex medical conditions, which included depressive illness, vascular mild cognitive impairment, coronary artery disease, hypercholesterolemia and hypertension.”

The first issue

23.  Dr Prabhakaran’s analysis of the first issue is to be found in Section I of his report. I highlight the following points.

24.  First, when Mother executed the 2008 will, she was suffering from two psychiatric conditions, namely vascular mild cognitive impairment (“vascular MCI”) and depression. These two conditions are a disorder of the mind and “could well have compromised her mental capacity”: see paras 64 and 67 of the report.

25.  Second, there is the possibility that Mother was suffering from insane delusions.

(1) There was inadequate exploration by Dr Ben Cheung as to Mother’s rationale for disinheriting Vivien in the 2008 will and there was no evidence that Dr Ben Cheung fully explored or challenged Mother’s views regarding Vivien to consider the potential of these beliefs being irrational or delusional in nature.

(2) Dr Prabhakaran therefore concludes that Dr Ben Cheung’s assessments “do not provide conclusive or reliable views regarding Mother’s testamentary capacity”: see paras 77 to 84 and 94 of the report.

(3) Dr Prabhakaran further opines that if the court decides that Mother’s views about Vivien were factually inaccurate, there is a possibility that Mother was harbouring irrational beliefs or insane delusions about Vivien which could have poisoned Mother’s affections towards the daughter and caused Mother to alter her testamentary disposition: see paras 86 to 89 and 95 of the report.

26.  Third, Mother’s insane delusions would be due to her vascular MCI and depression.

27.  Earlier, in the report, Dr Prabhakaran discusses in general the possible linkage between each of these two conditions and delusional thinking, at paras 65 to 67.

“65. Long-term depression can have serious effects on a person’s mental health, particularly in older people. This can sometimes lead to severe issues like having false beliefs … When someone is chronically depressed, it can change the way they think, causing them to see things in a more negative light than they really are. … In some extreme cases, these altered views can develop into delusional thinking, where a person strongly believes in things that aren’t true.

66. Vascular Mild Cognitive Impairment (VaMCI) … This condition can lead to frontal-subcortical circuit dysfunctions, which could manifest as executive dysfunction, impaired judgments, and, in some cases, delusions. …

67. … The long-term effects of [Mother’s] depression and vascular cognitive issues could well have led to delusional thinking, impacting her decision-making capabilities significantly when making her will.”

28.  Later, at para 96, Dr Prabhakaran confirms that if Mother suffered from delusional thinking, that would be due to the two psychiatric conditions. He writes:

“If the Court determines that Mother’s beliefs about Vivien Chen are false and would have caused her to alter her testamentary disposition, this would be due to a disorder of mind, in my opinion. The combination of medical factors namely vascular mild cognitive impairment and depression is likely to have affected mother’s thought process depriving her of the necessary clarity of thought to enable her to make a rational decision or affected her natural feelings for her daughter, Vivien Chen or her sense of right. …”

The second issue

29.  Dr Prabhakaran’s analysis of the second issue is to be found in section J of his report. I highlight the following points.

30.  First, he discusses in general a list of “red flags” which point to potential risk of undue influence. These include the social environment of the testator, vulnerability of the testator, and circumstances surrounding the making of the will: para 98 of the report.

31.  Second, he elaborates on the vulnerability factors and says that a number of mental disorders can increase vulnerability to undue influence. He says:

“100. … A range of mental disorders, including cognitive impairment, schizophrenia, paranoid and mood disorders, can predispose individuals to undue influence. Cognitive disorders can make individuals vulnerable to influence due to impaired judgment and altered perceptions of others.

101. Multiple health conditions, such as cognitive impairment, mental health disorders, and terminal illnesses, can increase vulnerability to undue influence.”

32.  Third, he points out that one should therefore evaluate a range of matters in order to determine the risk factors for undue influence, including medical and psychiatric history, personal history, will-making pattern, mental state, and cognition: para 106.

33.  Fourth, Dr Prabhakaran then discusses the red flags in Mother’s case. At para 111, he writes (in part, relying on Vivien’s pleaded allegations):

“… these factors include changes in trusted relationships, family conflicts, and psychological dependency on Angela. Limited social connections, coupled with cognitive or mood disorders, have been linked to increased susceptibility to influence. These factors seem relevant in Mother’s case. Consequently, they increase the likelihood that the testator (Mother) may comply with someone’s suggestions or wishes against their will.” (underline added)

34.  At para 113, Dr Prabhakaran concludes that Mother was a vulnerable person and had an increased susceptibility to undue influence because of, among other factors, “her multiple medical conditions, including depression and vascular mild cognitive impairment” at the time of the making of the 2008 will.

Two observations

35.  I wish to make two observations on Dr Prabhakaran’s report which are pertinent to the approach which the court should adopt when disposing of the striking out application.

36.  First, the two psychiatric conditions which Dr Prabhakaran says Mother suffered from, namely vascular MCI and depression, feature prominently in both the first and second issues, although they operate in different ways under the two issues.

(1) Under the first issue, the two conditions could have compromised Mother’s mental capacity.

(2) Also, under the first issue, the two conditions could have led to Mother’s insane delusions (subject to the court’s factual finding on Mother’s beliefs about Vivien being mistaken).

(3) Under the second issue, the two conditions, together with other non-medical “red flags”, made Mother more susceptible to undue influence.

37.  Second, the topic of insane delusion forms an important part of Dr Prabhakaran’s discussion of the first issue but does not feature and is not relied on in his reasoning under the second issue.

VIVIEN’S FIRST GROUND

38.  In this striking out application, the first ground put forward by Vivien is that the paragraphs in question focus on the first issue of testamentary capacity, in particular whether there is a disorder of the mind and insane delusion, with the latter being given a prominent focus. Under the Order, Angela was not granted to leave to file any further evidence under that issue. Hence those paragraphs ought to be struck out.

39.  In fact, in the Reports, Angela’s experts expressly accept that their task is to address the second issue only. However, they go on to say that in order to do so, they would have to address the first issue as there are overlaps between the issues. I quote the relevant paragraphs below.

40.  Dr CK Wong refers to Dr Prabhakaran’s discussion of Mother’s medical conditions under both issues:

“As I have been asked only to address the 2^nd Expert Issue, I will confine my opinions accordingly. … And for that matter, I would like to point out that there are overlaps between the 1^st Expert Issue and the 2^nd Expert Issue since the 2^nd Expert Issue asks about the susceptibility of Mother to undue influence by reason of her alleged medical conditions and the discussion of these alleged medical conditions featured prominently in Dr Prabhakaran’s opinion on the 1^st Expert Issue. Therefore, while I will focus myself on the 2^nd Expert Issue, my discussion of the Mother’s alleged medical conditions will invariably touch on the 1^st Expert Issue. Nevertheless, I will confine my expert opinions to the 2^nd Expert Issue.” (underline added) (para 37)

41.  Dr Ben Cheung describes the two issues as “clinically intertwined”. He writes:

“This report has been prepared to address the 2^nd Expert Issue in this case: whether Madam Yang was susceptible to probate undue influence by reason of her medical conditions. While the primary focus herein is on her vulnerability to such influence, it is essential to first address the related 1^st Expert Issue of her testamentary capacity, as these two matters are clinically intertwined. A thorough evaluation of Madam Yang’s susceptibility to undue influence requires understanding of her cognitive and emotional state, as well as her capacity to make independent and reasoned decisions about her will. Thus, addressing testamentary capacity is not only relevant but necessary to fully contextualize and assess the potential for undue influence.” (para 9)

42.  Similarly, Dr John Wong refers to the “intersect” of the two issues:

“I am fully aware that the objective of this report is to provide my expert opinion on Madam Yang’s susceptibility to probate undue influence by reason of her medical condition (or 2nd Expert issue). However, to adequately address this task, it is necessary for me to address certain medical considerations (eg presence of disorder of the mind) which may intersect with the 1st Expert issue. Consequently, while my comments will be confined to the 2nd Expert issue, minor overlaps with the 1st Expert issue may be unavoidable.” (para 5.5)

Complaint about Dr CK Wong’s report

43.  As regards Dr CK Wong’s report, Vivien takes issue with Part D of the report which is entitled “Delusions”. This part comprises 57 paragraphs, which takes up 24 pages.

44.  In this part, Dr CK Wong first sets out his understanding of Dr Prabhakaran’s opinion about delusions, and states, at para 167, that it is necessary for him to consider delusions as an independent topic.

45.  At para 168, the doctor comments that delusions must be due to one or more psychiatric disorders. It is notable that here Dr CK Wong comments that these disorders include neurocognitive disorder and depression, but then he says:

“As I have already ruled out these two disorders. I will not refer to them further in Part D.”

46.  At para 172, he goes on to identify two disorders which may be relevant in Mother’s case: delusional disorder and shared psychotic disorder. He acknowledges that Dr Prabhakaran has not mentioned them in his report:

“In this regard, I would like to point out that Dr Prabhakaran has not mentioned these two disorders. In other words, I am conducting an even more rigorous assessment into this case. This is a necessary assessment as delusion per se is a crucial consideration in cases of suspected probate undue influence.”

47.  Then, he refers to Mother’s changed thought about Vivien and considers the possibility that such changed thought was persecution delusion in nature and hence irrational: paras 173 to 184.

48.  It is in this context that Dr CK Wong comes to the view that this would require looking into when Father became a mentally incapacitated person and how severe his condition was. This is because one of Mother’s changed thought was that Vivien had taken advantage of Father’s deteriorated cognitive function. He is of the view that in order to evaluate whether this changed thought was irrational, one needs to appraise the change in Father’s cognitive function.

49.  I quote his reasoning at para 185:

“… my opinion is that the central theme of Mother’s changed thought about Vivien is that Vivien had taken advantage of Father’s deteriorated cognitive function. We need to ask the most salient question, i.e., whether Mother’s changed thought was irrational. In order to answer this question, we need to have a factual appraisal of the change in Father’s cognitive function. In conducting this factual appraisal, the question is not whether Father was an MIP (that Father was an MIP was an undisputed fact in this case; he was declared an MIP in November 2008, §101, AS) but when he became one and how severe was his condition.” (original emphasis)

50.  It is unnecessary to set out here Dr CK Wong’s reasoning in relation to the timing of Father’s mental incapacity and the rationality of Mother’s belief. At the end, he concludes that Mother’s changed thought about Vivien was not irrational: paras 197 and 202. He further concludes, at para 202, that Mother did not suffer from delusional disorder or shared psychotic disorder, and that her changed thought about Vivien was rational in nature.

51.  It is Vivien’s submission that when Dr Prabhakaran discusses delusion, he does so only in the context of the second issue of susceptibility to undue influence. However, Dr CK Wong deals with the issue of delusion plainly in the context of the first issue of testamentary capacity. That should not be allowed.

Complaint about Dr Ben Cheung’s report

52.  It is Vivien’s submission that in the paragraphs objected to, Dr Ben Cheung attempts to deal with the issue of disorder of the mind and insane delusion which impacted on Mother’s testamentary capacity. This clearly pertains to the first issue. Dr Ben Cheung also gives a point-by-point “defence” against Dr Prabhakaran’s critique of how he arrived at his conclusion in the historical reports covering his examination of Mother prior to her making the 2008 will. Again, that pertains to the first issue.

53.  For these reasons, Vivien contends that the paragraphs objected to should be expunged.

Complaint about Dr John Wong’s report

54.  Similarly, in Dr John Wong’s report, in the paragraphs in question, he states his views in relation to disorder of the mind and insane delusions. Both relate to the first issue and should be disallowed.

Discussion

55.  The Order was made after a contested hearing, in exercise of the court’s case management power. In the absence of any variation, its terms should be adhered to.

56.  It is plain that no leave was granted in the Order to Angela to file further evidence on the first issue subsequent to Dr Prabhakaran’s report. Hence, where the Reports contain entire sections or parts (save for passing references in isolated paragraphs) which deal purely with the first issue, they are included without leave of the court and are liable to be struck out (unless fresh leave is granted). This must be the starting point of the present discussion.

57.  As a matter of fact, Angela’s experts all expressly acknowledge in the Reports that their task should be confined to discussing the second issue.

58.  Mr Paul Shieh, SC, appearing with Mr Alexander Tang and Mr James Man for Vivien, submits that if Angela wishes to go into areas beyond the permitted scope, what she ought to do is to seek further leave to admit such evidence. Whether the evidence should be admitted can then be properly debated based on general case management principles applicable to the grant of expert directions. I agree with this submission.

Discussion: the two psychiatric conditions

59.  Mr Shieh further submits that what Angela should not do, but has done, is to shoehorn very substantial amounts of expert evidence on an excluded issue into the permitted issue by putting forward various purported justifications, eg, that there is overlap between the excluded issue and the permitted issue.

60.  I do not entirely agree with this submission. I refer to the first observation which I have stated in para 36 above. There is indeed overlap between Dr Prabhakaran’s opinions expressed under the first and second issues – the two psychiatric conditions of vascular MCI and depression feature prominently in both issues. It follows that insofar as Angela’s experts are commenting on the two medical conditions, such evidence can properly be regarded as given in relation to the second issue. Such evidence would have an ultimate impact on the answer to be given to the second issue. For that reason, such evidence comes within the scope of the second issue and should be allowed.

61.  In this regard, I agree with what Dr CK Wong says in para 37 of his report (the underlined part, see para 40 above) where he explains why his discussion of the second issue would invariably touch on the first issue.

62.  It is Vivien’s position that she is not trying to shut out any substantive discussion of the underlying medical conditions of Mother. Furthermore, at the hearing on 3 September 2025, Mr Shieh accepted that where the paragraphs under objection discuss the two psychiatric conditions, they are relevant to the second issue, even though they are at the same time also relevant to the first issue. What Vivien finds objectionable is that the paragraphs in question are directed at ultimately answering the first issue of testamentary capacity, including whether insane delusion exists in the Banks v Goodfellow sense. That, Mr Shieh submits, is impermissible. He further submits that it would be for Angela’s experts to reformulate their reports in such a way that the two psychiatric conditions are discussed in the context of the second issue, and if done properly, they may come within the scope of the second issue.

63.  In a way, I can understand Vivien’s grievance. She feels that by making use of the opportunity to comment on the two medical conditions, Angela is having a second chance to put in more evidence to support her case of testamentary capacity when she has no leave to do so under the Order. However, in my view, the material point here is that, in light of Dr Prabhakaran’s opinions, the two conditions are indeed relevant to the second issue. For that simple reason, Angela’s experts should be allowed to discuss them, as permitted under the terms of the Order. I fail to see what can be gained by asking them to reformulate the Reports as suggested by Mr Shieh. One looks at substance rather than form.

64.  The hearing on 3 September 2025 was adjourned part-heard as there was not sufficient time for counsel to complete their submissions. I directed Vivien to submit a revised list of paragraphs to be expunged by taking out those paragraphs in which the two psychiatric conditions were discussed.

65.  In the revised list, Vivien maintains their original objection to Dr CK Wong’s report in whole. As regards Dr Ben Cheung, Vivien has substantially narrowed down their objection to only Section E of the report. As for Dr John Wong, she now only objects to Section D5 of his report.

66.  Applying the approach set out in para 60 above, I am of the view that the paragraphs removed from the original list should not be expunged.

Discussion: delusion

67.  Looking at the remaining items in the revised list, the major complaint made by Vivien is that Angela’s experts have devoted substantial parts of the Reports to the issue of insane delusions. This complaint applies in particular to Dr CK Wong’s report.

68.  In this regard, I refer to the second observation which I have stated in para 37 above. It seems clear to me that where the expert is dealing solely with the issue of delusion, ie not touching on, or by reference to, the two psychiatric conditions, that is evidence squarely within the first issue and has nothing to do with the second issue. Hence, they should be expunged as evidence filed without leave. This is the approach which I shall adopt below.

69.  In arriving at this conclusion, I have considered the contentions made by Mr Yu, based on which he submits that the opinions of Angela’s experts expressed on the topic of delusion should be admitted, as the opinions fall within the second issue. I do not agree with these contentions, which I would summarise under four points, and will now deal with them one by one.

70.  The first contention represents what Mr Yu described in his oral submissions as Angela’s primary position, which is this.

(1) Whether Angela’s experts should be allowed to discuss delusion does not turn on what Dr Prabhakaran has said in his report. This is because para 6 of the Order granted leave to Angela to adduce “additional” expert evidence on the second issue, and not only reply or responsive evidence. The scope of the second issue is therefore not dictated by what Dr Prabhakaran says.

(2) Hence, even if (which is not accepted) Dr Prabhakaran does not expressly mention delusion in his discussion of the second issue, it does not matter. As long as Angela’s expert opinions on delusion are relevant to the second issue, they should be allowed.

(3) Here, the topic of delusion is clearly relevant to the second issue because Vivien, in her pleadings, relies on Mother’s allegedly delusional beliefs for both lack of testamentary capacity and undue influence: see paras 90A to 90B and para 125 of the re-re-amended defence and counterclaim, respectively. The issue of delusion is therefore an issue raised on the pleadings in relation to undue influence.

71.  I do not agree with each of the sub-points made under this first contention.

(1) I think that too much is being read into the word “additional” in the Order. When one looks at the overall structure of the Order, it is quite clear that any further evidence to be filed by Angela should be responsive to Vivien’s evidence. In the first round of the evidence, Angela was to rely on the 16 historical reports for the second issue. In other words, Angela had already had her say on the second issue by relying on the contents of those 16 reports. It seems unlikely that the court intended to then give her a free hand in the second round to adduce evidence unrelated to what Vivien’s expert says. This is not the usual way in which the court gives expert directions. There seems no good reason why Angela would be allowed to “wait and see” and be at liberty to produce evidence in the second round which she could have given (if she wanted to) in the first round.

(2) Hence, I find that, as a matter of proper construction of the Order, Angela may only file responsive evidence under para 6. Hence, where a topic is not canvassed by Dr Prabhakaran, Angela is not permitted to file evidence on the topic.

(3) In any event, if I am wrong about this, I take the view that the topic of delusion is not relevant to the issue of undue influence. This is not an issue raised on the pleadings. Vivien’s pleaded case on undue influence, as contained in Section H of her re-re-amended defence and counterclaim, is that Mother held various mistaken and irrational beliefs. It is not part of the pleaded case that these beliefs were delusional beliefs at the same time. This is so notwithstanding that there is a reference in para 125 (on which Mr Yu relies) to one of the beliefs as being an insane delusion.

(4) At the hearing, Mr Shieh confirmed that the above reflects the pleaded case of Vivien. Furthermore, it was confirmed on behalf of Vivien that it is not part of her case that the (alleged) fact that Mother was suffering from delusion would cause her to be more susceptible to undue influence.

(5) Given the above interpretation of the pleadings and Vivien’s express confirmation regarding her case on undue influence, I am in a position to conclude now that Mother’s alleged delusion is not relevant to Vivien’s case of undue influence. Therefore, Angela should not be allowed to put in evidence regarding delusion under the second issue.

72.  The second contention made by Vivien is what Mr Yu described in his oral submissions as Angela’s secondary position, which is that if Angela can only file reply evidence in response to Dr Prabhakaran’s report, Dr Prabhakaran is being ambiguous as to whether he is relying on delusion in the second issue. In the circumstances, Angela’s experts should be allowed to discuss the issue of delusion too under the second issue.

73.  I believe that this submission may have been made on the strength of what Dr CK Wong says in para 35 of his report. In short, while Dr CK Wong acknowledges that Dr Prabhakaran only mentions vascular MCI and depression in his discussion of the second issue, given the extensive discussion of delusions in the earlier parts of Dr Prabhakaran’s report, Dr CK Wong considers that Dr Prabhakaran is in effect also relying on delusion when opining on the issue of susceptibility to undue influence. This is what Dr CK Wong says:

“35. … Hence, it seems to me that Dr Prabhakaran is of the opinion that at the material time when Mother made the 2008 Will, she was under the effects of two active psychiatric conditions, i.e., depression and vascular mild cognitive impairment, and she probably also had delusional thinking, and his conclusion was that Mother was probably susceptible to probate undue influence. Dr Prabhakaran may like to clarify if he thinks I have misunderstood him.

36. Thus, to explain why I disagree with Dr Prabhakaran and why I do not think Mother was susceptible to probate undue influence, I need to discuss three major psychiatric topics, in response to the three psychiatric conditions put forward by Dr Prabhakaran as referred to in the previous paragraph. The three major psychiatric topics are: the Neurocognitive Disorders; Major Depressive Disorder; and Delusions. …” (original emphasis)

74.  I refer to the second observation which I have stated in para 37 above. For that reason, I agree with Mr Shieh’s submission that Dr CK Wong is misinterpreting Dr Prabhakaran’s opinion under the second issue. As Dr Prabhakaran does not rely on delusion in the second issue, Angela’s experts should not be allowed to discuss delusion in their reports.

75.  The third contention is as follows. Dr Prabhakaran’s diagnosis that Mother suffered from delusions is based on the same two health conditions on which he relies to find that Mother was vulnerable to undue influence, namely vascular MCI and depression, there is therefore clearly a close connection between delusions and the second issue. It is submitted on behalf of Angela that it is difficult to see how Vivien can seek to shut out the discussion by Angela’s experts on these issues.

76.  I do not agree with the contention. There is overlap between Dr Prabhakaran’s answers to the first and second issues. I have set out the precise scope of the overlap in my first observation (see para 36 above). Notwithstanding that, I repeat my second observation, namely that delusion is not relied on by Dr Prabhakaran in arriving at his conclusion in the second issue, there is therefore nothing wrong to disallow Angela’s experts to talk about delusion under the same issue.

77.  The fourth contention is that Dr Prabhakaran applies a holistic approach to the issue of susceptibility to undue influence, without being limited to the medical condition pleaded by Vivien. Angela’s experts cannot be criticised for addressing the issue of Mother’s susceptibility to undue influence by also adopting a holistic approach of considering all factors which are relevant in the individual expert’s professional opinion, including the issue of delusion.

78.  I do not consider this to be a valid argument. I repeat my second observation. The short point here is that under the terms of the Order, Angela is not entitled to adduce expert evidence which is not in response to Dr Prabhakaran’s report.

79.  Furthermore, as Dr Prabhakaran is not relying on Mother’s (alleged) delusion to show her susceptibility to undue influence, in the circumstances, one must wonder why Angela’s experts would want to spend time to disprove the delusion in order to show that Mother was not susceptible to undue influence due to delusion.

80.  It is, in my view, illogical to allow Angela’s experts to discuss something which Dr Prabhakaran does not rely on. On this point, I refer to Dr CK Wong’s own remark as quoted in para 46 above. He takes the initiative to talk about two disorders which Dr Prabhakaran does not mention, and ultimately reaches the conclusion that the two disorders do not apply to Mother. I appreciate that this may be an attempt on Dr CK Wong’s part to provide the court with a comprehensive and holistic analysis on delusion. However, as a matter of case management, the court applies a focused approach and deals only with issues which are in dispute. The holistic approach, which Vivien says her experts are adopting, is not necessary for the proper conduct of the action.

81.  In short, evidentially, the issue of delusion in the context of undue influence simply does not arise. The court should not allow the parties to spend time and incur costs on adducing expert evidence on a non-issue.

Rulings under Vivien’s first ground

82.  Applying the approach which I set forth in paras 60 and 68 above, I now make my rulings in respect of each of the Reports.

83.  As regards Dr CK Wong’s report, the paragraphs under objection deal with the issue of delusion. That is squarely evidence which comes under the first issue only. Those paragraphs should be expunged.

84.  As regards Section E in Dr Ben Cheung’s report, Vivien’s complaint is that it deals with the issue of testamentary capacity and should therefore not be allowed.

85.  It is true that a large part of the section is devoted to responding to, and defending against, Dr Prabhakaran’s criticisms of the mental assessment conducted by Dr Ben Cheung for the 2008 will. That assessment was of course conducted for the purpose of ascertaining Mother’s testamentary capacity. That amounts to evidence under the first issue. However, as the assessment was about whether Mother suffered (or did not suffer) from any psychiatric condition, the discussion surrounding the assessment also comes within the second issue, applying the approach set out in para 60 above.

86.  I quote below some of the discussions regarding Mother’s medical conditions as examples:

“… These assessments also confirmed her stable mental status, as evidenced by consistent MMSE scores of 28-29, absence of psychiatric illness, and precise recall of her family history. …” (underline added) (para 59)

“… Madam Yang displays no indication of mental illness. Her thought processes were intact, without disorder or delusions. Her cognitive functions were consistent with her age. In my professional opinion, there is no mental disorder present that would compromise her ability to understand and manager her personal affairs …” (underline added) (para 60)

“Therefore, Madam Yang’s testamentary capacity on 15 February 2008 is well-supported by her consistent cognitive stability, rational decision-making, and selective disclosure reflecting autonomy. My assessment adhered to Banks v Goodfellow standards, balancing clinical diligence with respect for her privacy.” (underline added) (para 73)

87.  It appears to be the case that in some of the paragraphs in the reminder of the section, Dr Ben Cheung discusses matters relevant to the other Banks v Goodfellow criteria which do not concern the mental condition of Mother. As such, it may be said that such evidence is evidence solely under the first issue. However, in this application, the burden is on Vivien to single out these paragraphs for striking out, instead of asking the court to expunge the entire section. She has not done so, whether at the time of taking out the summons or subsequently when given a chance to revise her list during the part-heard adjournment.

88.  All things considered, I think the proper thing to do is to allow the whole section to stay.

89.  Lastly, as regards Dr John Wong’s report, the section which is still being objected to is Section D5. In this section, the doctor expresses his opinion that Madam Yang was not under the effect of an insane delusion when she executed the 2008 will. In the main, his reasoning does not touch on, or refer to, Mother’s psychiatric conditions. Applying the approach set out in para 68 above, that is evidence squarely within the first issue and has nothing to do with the second issue. Hence, they should be expunged.

VIVIEN’S SECOND GROUND

90.  The second striking out ground relates to paras 185 to 196 of Dr CK Wong’s report only. They are part of Part D (“Delusion”) and contain a discussion of when Father lost his mental capacity and the severity of his condition. The rationale for Dr CK Wong embarking on this discussion is set out in para 49 above.

91.  The discussion goes to the issue of delusion, and does not concern the two psychiatric conditions which Dr Prabhakaran says affected Mother. Hence, applying the approach set out in para 68 above, the paragraphs are evidence under the first issue, which is outside the scope of the Order. For that reason, they should be expunged.

92.  If I am wrong about this in that they are within the scope of the Order, they still should not be allowed to stay since it is obvious that the issue of Father’s mental condition is itself a standalone topic, for which express leave ought to have been (but was not) sought. There can be no dispute that an investigation into the specific questions of when Father began to lose his mental capacity and how severe his condition was would be a substantial exercise, with significant time and costs to be spent by both sides (and the court) on examining his medical history and voluminous medical records. It can also be expected to be a hotly contested issue. I do not believe that all these factors relevant to whether leave should be granted for these specific questions had been canvassed at the hearing before Wilson Chan J. When making the Order, his Lordship could not have intended to allow the experts to embark on such an investigation.

93.  In any event, no leave ought to be granted to parties to adduce evidence on these issues concerning Father as the exercise is plainly disproportionate when one considers the usefulness of such evidence against the costs needed to be spent on obtaining the evidence.

94.  I am prepared to accept that the objective fact of the timing and severity of Father’s mental condition would in theory be relevant to ascertain Mother’s subjective perception of his condition. For instance, if Father’s outward appearance shows a clear-cut case of someone plainly losing his mental capacity, then this must have a bearing on how Mother perceived his condition to be. But, as things stand, how Father had behaved and interacted with others is hotly disputed, as a matter of factual evidence. The issue itself being a controversial one, it is doubtful how helpful it would be to make use of this evidence to evaluate Mother’s subjective perception. Given that significant time and costs will have to be spent on adducing evidence on Father’s mental condition, it is clear to me that the exercise is going to be a disproportionate one and should not be allowed.

ANGELA’S ALTERNATIVE POSITION

95.  Lastly, I should deal with Angela’s alternative position, which is stated in the last paragraph of her skeleton submissions. She asks that if the court rules that the paragraphs under objection are to be expunged, for those which are relevant to the first issue, the court should grant retrospective leave to Angela to include them in the Reports, and on that basis these paragraphs can be adduced both for the purposes of the joint meeting of the experts and the joint report, and for the purposes of the trial.

96.  I decline to accede to this suggestion.

97.  In this application, the stance of Angela, as expressed by her experts in the Reports and through counsel’s submissions, is that the paragraphs under objection are within the scope of the Order. Both the written and oral submissions made on her behalf were devoted to substantiate that stance. I have ruled against that position. If Angela now wishes to seek leave to include those paragraphs, there should be a proper debate of the applicable case management considerations governing expert directions before the court makes a decision.

98.  It is not enough for Angela to simply assert that the evidence is relevant (to the first issue) and hence should be admitted. Relevance is of course a prerequisite. But it is not the only criterion. The court would need to be satisfied that the expert evidence is required for the just resolution of the issues before the court: see, eg, Chok Yick Interior Design & Engineering Co Ltd v Lau Chi Lun HCA 1480/2008, 5 May 2010, para 9. In answering this question, one would consider how helpful the evidence is going to be to assist the court to arrive at a decision: see, eg, Wong Hoi Fung v American International Assurance Co (Bermuda) Ltd [2002] 3 HKLRD 507 at para 12. Balanced against the usefulness of the proposed evidence, the court also needs to come to a view on whether the time and costs expected to be spent on the exercise would be worthwhile and proportionate.

99.  All these factors are not explored by Angela in respect of the paragraphs under objection. It is not a simple matter of just allowing these paragraphs to stay in the Report. One needs to consider whether Vivien then has a right to respond. In the end, one also asks the question whether it is justifiable for time and costs to be spent on such evidence at the trial. All these matters are not discussed. In the circumstances, it is not proper for me to grant retrospective leave to admit them into the evidence.

CONCLUSION

100.  In conclusion:

(1) The paragraphs which Vivien objects to in Dr CK Wong’s report should be expunged. I therefore order that para 1 of Vivien’s summons be granted.

(2) The paragraphs which Vivien objects to in Dr Ben Cheung’s report should stay. I therefore order that para 2 of the summons be dismissed.

(3) Section A of Dr John Wong’s report is allowed whereas Section D5 should be expunged. I therefore order that para 3(a) of the summons be dismissed and para 3(b) be granted.

(4) There be liberty to apply.

101.  Vivien succeeds in some of her requests and Angela succeeds in resisting the others. I consider that it would be appropriate to make the costs of the summons to be part of the costs of the action. I make a costs order nisi that the costs of the summons, including all reserved costs, be in the cause, with a certificate for three counsel.