Justice Ribeiro PJ
In these appeals, the proper approach to appointing a guardian ad litem in respect of a mentally incapacitated person falls to be considered.
A. The background
The plaintiff is a licensed money lender. It lent the defendant (“Mr Law”) $30,000 (with interest at 47.4% per annum). When he defaulted in making repayments, it brought proceedings in the District Court, obtaining judgment against him, a charging order on his flat and an order for vacant possession and sale, all in default of acknowledgment of service by Mr Law. After the plaintiff had obtained vacant possession and entered into a provisional agreement for the sale of the flat, Madam Cheung, Mr Law’s wife, approached the Court contending that Mr Law was a mentally incapacitated person. With the help of solicitors, she issued a summons seeking orders that she be appointed his guardian ad litem and that the judgment and consequential orders be set aside, claiming that Mr Law did not understand the loan transaction. Medical reports by a psychiatrist and a clinical psychologist were filed in support. Pending resolution of the dispute, the plaintiff agreed not to proceed with the provisional sale.
B. The decisions in the Courts below
Deputy District Judge R Yu summarised the effect of the medical evidence filed by Madam Cheung as follows:
It is the opinion of Dr Ng Fung Shing that the Defendant has a full scale IQ score of 62 which indicates he is a mild grade mentally handicapped person. He has been a slow learner since birth and has studied in special school before. Because of his impaired intelligence, he has poor ability in comprehension. He cannot do even simply calculation. He fails to tell the nature of a contract even in broad terms. Dr Ng is of the opinion that the Defendant failed to understand the exact nature of a loan agreement and lack the mental capacity to enter into any contract in the form of loan agreements. The psychologist Dr Ng Kee On also commented that the Defendant is suffering from a significant intellectual dysfunction, functioning in the mildly handicapped spectrum of intellectual ability. The Defendant is likely to encounter difficulty in his daily activity including the handling of simple financial transaction.
Subsequently, his Honour directed that Mr Law be examined by two psychiatrists, one (Dr Chung See Yuen) appointed by the plaintiff and the other (Dr Ng Fung Shing) by Madam Cheung, and that they produce a joint report. The effect of the joint report was summarised by the Judge as follows:
In essence, both doctors agreed that the Defendant has a full scale intelligence score of 62 and the Defendant has been functioning in the mild grade mentally retarded range. Dr Ng maintains his opinion that the Defendant is incapable of instructing lawyers in relation to the present proceedings because of his mental incapacity. Dr Chung opines that the Defendant is not incapable of managing and administering his property and affairs. Dr Chung believes the Defendant would understand the nature of the loan agreement and he is capable of instructing lawyers now in relation to the present proceedings.
If Mr Law was indeed a mentally incapacitated person, Order 80 r 2(1) of the Rules of the District Court would have precluded him from acknowledging service or defending the proceedings except by his guardian ad litem. However, in line with the plaintiff’s resistance to her appointment, the Judge refused to appoint Madam Cheung as guardian ad litem. In reaching that decision, he had regard to the joint psychiatric report and also viewed two videos showing communications between Mr Law and someone described as a referral agent who would assist him in getting loans. He rejected the view expressed in the report of Dr Ng in favour of that of Dr Chung and held that it had not been established that Mr Law was incapable of managing and administering his property and affairs or giving instructions to his legal advisors.
Since Madam Cheung was denied locus as Mr Law’s guardian ad litem, the Judge dismissed her application to set aside the default judgment and consequential orders.
On 23 April 2013, the Judge refused the plaintiff’s application to vary the costs order made and Madam Cheung’s application for leave to appeal, elaborating on the basis upon which he had refused to appoint her Mr Law’s guardian ad litem, to which I shall return.
The Court of Appeal (which subsequently granted leave) upheld the Judge’s decision.  Cheung JA, reviewed certain authorities and supported the Judge’s approach which involved considering whether Mr Law was capable of understanding the issues on which his consent or decision were likely to be necessary in the course of the proceedings, in the light of the medical and other evidence placed before the Court. His Lordship rejected the argument that the Judge had adopted an inappropriately high standard more apposite for other types of inquiry into mental capacity.
Leave to appeal to this Court was granted by the Appeal Committee on the basis that questions of the requisite importance arise on the appeal concerning:
the correct approach in law to deciding whether a person should be allowed to act as guardian ad litem with a view to protecting the interests of a person sued as defendant, who is alleged to be a mentally incapacitated person; and
the appropriateness of permitting the plaintiff in such cases to oppose such intervention by the proposed guardian ad litem.
C. Errors in the judgments below
In my view, with respect, the Courts below:
adopted the wrong approach to, and the incorrect test of, mental incapacity in refusing to allow Madam Cheung to act as Mr Law’s guardian ad litem; and
erroneously allowed the plaintiff, whose interests are obviously adverse to those of Mr Law, to resist her appointment to defend the proceedings it had brought, so that the default judgment was upheld without the plaintiff’s claim ever being tested on its merits.
D. The correct approach to the appointment of a guardian ad litem
The appointment of Madam Cheung as guardian ad litem for Mr Law ought to have been simple.
RDC Order 80 provides for how a “person under disability” participates in legal proceedings. As we have seen, it precludes a person under disability from defending proceedings save by a guardian ad litem. It defines a “person under disability” as “a person who is a minor or a mentally incapacitated person”.
Order 80 r 1 then defines “mentally incapacitated person” to mean:
.... a mentally disordered person or a mentally handicapped person (within the meaning of the Mental Health Ordinance (Cap 136)) who, by reason of mental disorder or mental handicap, as the case may be, is incapable of managing and administering his property and affairs ....
By section 2 of the Mental Health Ordinance (“MHO”), “mentally handicapped person” is defined as “a person who is or appears to be mentally handicapped”, and “mental handicap” is defined to mean:
.... sub-average general intellectual functioning with deficiencies in adaptive behaviour, and ‘mentally handicapped’ shall be construed accordingly;
MHO section 2 goes on to define “sub-average general intellectual functioning” to mean:
.... an IQ of 70 or below according to the Wechsler Intelligence Scales for Children or an equivalent scale in a standardized intelligence test.
It was common ground that D had an IQ of 62. So Mr Law plainly fell within the statutory definition of “mentally handicapped person” and thus within the definition of “mentally incapacitated person” in Order 80 r 1.
Madam Cheung (who was unrepresented before the Judge) took the step of issuing a summons seeking an Order that she be appointed Mr Law’s guardian ad litem. However, such an Order was not needed. In their judgments, the Courts below do not mention Order 80 r 3(2) which provides:
Except as provided by paragraph (4) or (5) or by rule 6, an order appointing a person next friend or guardian ad litem of a person under disability is not necessary.
By the combined effect of Order 80 r 3(6)(c) and Order 80 r 3(8), a person under disability is entitled to appear by his guardian ad litem if specified documents have been filed in court. Most importantly, there must be a certificate made by the solicitor representing the person under disability stating that the solicitor knows or believes that the person in question is a mentally incapacitated person, giving the grounds of his knowledge or belief; and stating that the proposed guardian ad litem has no interest in the matter adverse to that of the person under disability.
As we have seen, Mr Law’s IQ of 62 being common ground, he was plainly a “mentally handicapped person”. The requirement that he was incapable of managing and administering his property and affairs by reason of such mental handicap, did not require an inquiry by the Court provided that the solicitor instructed by Madam Cheung was prepared to certify that he or she knew or believed Mr Law to be so incapable. As we have seen, the solicitor would have had ample grounds for so certifying on the basis of the opinions of Dr Ng Fung Shing and Dr Ng Kee On which were relied on in making Madam Cheung’s application to the Court. Madam Cheung had given her written consent to act as guardian ad litem and the solicitor would have been able to certify that she had no interest in the matter adverse to that of her husband, Mr Law.
Upon filing such documents in the Registry, Madam Cheung would, in accordance with Order 80 r 3(6)(c), have been entitled to appear as Mr Law’s guardian ad litem without any application to the Court. The statutory procedure is obviously designed to avoid unnecessary satellite litigation over mental capacity in ordinary cases involving persons under disability.
I might add in passing that the assumption by a next friend or guardian ad litem of that role without prior inquiry by the Court may of course not be final. If, for instance, it is subsequently discovered that the person assuming the role is not acting in good faith or is otherwise unsuitable, or indeed, for any other good reason, the Court may appoint someone else in substitution for the person previously assuming the role. Moreover, if the person said to be under disability disputes any mental incapacity on his part, an inquiry may then be justified and the Court may order removal of the next friend or guardian ad litem.
E. Where the Courts below fell into error
E.1 Distinction between debarring orders and protective appointments
The principal error made by the Judge and upheld by the Court of Appeal involved a misapplication of the Court of Appeal’s judgment in Ho Po Chu v Tung Chee Wah. That was a case where the defendant, having been sued by the plaintiff, obtained a court order staying the plaintiff’s action unless and until she was represented by a next friend and solicitors were instructed. This was done on the basis that under Order 80 r 2, a person under disability may not bring a claim except by his next friend. When considering what, if any, evidence was needed to trigger such prohibition, Yuen JA drew an important distinction between subjecting someone to an adversarial debarring order (such as that sought by Mr Tung Chee Wah) and allowing someone (like Madam Cheung) to act in the role of a protective next friend or guardian ad litem:
It is therefore clear in my view that the Court should adopt a flexible approach to the evidence of mental incapacity under O 80. Where mental incapacity is relevant because a debarring order is sought, the court would expect clear medical evidence to prove the mental incapacity because the effect of a debarring order is to restrict a person's direct access to the court. However, where mental incapacity is relevant because an action is started by the next friend (or defended by the guardian ad litem) of a person said to be suffering mental incapacity and that act is obviously for the person's benefit, the court would not initially require formal medical evidence, although it would of course be prudent for the next friend or guardian ad litem (and the solicitor acting under his instructions) to have medical evidence available before the event in case of challenge.
Recognizing that a debarring order has the serious consequence of denying someone direct access to the courts, her Ladyship considered it appropriate to adopt a high evidential threshold for the making of such orders. She decided that it was proper to adopt the stringent requirements laid down in Part II of the MHO for applications to the court for an inquiry into “whether any person .... who is alleged to be mentally incapacitated is incapable, by reason of mental incapacity, of managing and administering his property and affairs”, being a procedure that could lead to a decision under MHO, s10 which would “place the estate of the mentally incapacitated person out of his reach”. Her Ladyship stated:
Although a debarring order only stays the proceedings until a next friend is appointed and solicitors are instructed, and so has a less draconian effect than a s 10 decision, given the effect on the person's direct access to the court and the stigma involved, in my view the court should require medical evidence of the same quality (even if not with the same formality) before it would make a debarring order. Certainly I cannot envisage a court making a debarring order without any medical evidence.
Yuen JA recognized that, in contrast, the Rules do not require a judicial inquiry before appointment of a protective next friend or guardian ad litem:
.... O 80 r 3(8)(c)(i) shows that an inquiry is not needed before a mentally incapacitated person can sue by his next friend (or defend by his guardian ad litem). That rule sets out the documents that should be filed in the Registry before a person can appear by his next friend or guardian ad litem. It provides that if a person proposing to be next friend or guardian ad litem has not been authorised to act as such under Pt II MHO, there must be filed in the Registry a certificate made by the solicitor for the mentally incapacitated person certifying (amongst other things) that he believes the person to whom the certificate relates is a mentally incapacitated person, giving the grounds of his belief.
It is easy to see the basis for the distinction drawn by Yuen JA which, with respect, was clearly sound. A defendant sued by someone whom he considers to be mentally incapacitated seeks protection from being vexed by that plaintiff by asking the Court to debar him or her from proceeding save by a next friend acting through a solicitor. A defendant seeking such an order is obviously in an adversarial position vis-à-vis the plaintiff and, unsurprisingly, is required to provide “clear medical evidence to prove the mental incapacity because the effect of a debarring order is to restrict a person's direct access to the court.” On the other hand, a person in Madam Cheung’s position, seeks to be allowed to act as Mr Law’s guardian ad litem to protect Mr Law’s interests in the face of the plaintiff’s suit. Madam Cheung is not acting in an adversarial position vis-à-vis Mr Law, but protectively. As Yuen JA points out, in such cases, the court does not require medical evidence, a solicitor’s certificate being sufficient.
The Judge failed to appreciate this distinction. Madam Cheung was unrepresented, but counsel for the plaintiff submitted that before appointing her as guardian ad litem, “[the] medical evidence required should be of a comparable quality to the requirement for the purposes of a Part II inquiry under the Mental Health Ordinance”. The Judge then referred to Ho Po Chu, and noted that Yuen JA said “that the debarring order is less draconian than a section 10 decision. But the court should require medical evidence of the same quality before it would make a debarring order.” His Honour concluded:
In this particular case, the finding that the Defendant is a mentally incapacitated person is a bar to the Plaintiff from pursuing this action against the Defendant until the appointment of guardian ad litem and appointment of solicitors. I agree with Mr Cheung that the medical evidence that should be adduced before such a finding should be made should be of the same quality as for a debarring order.
The Judge appears to have considered Madam Cheung’s application to be allowed to represent Mr Law an application to “bar the plaintiff from pursuing the action”, which was plainly erroneous. There was no question of the plaintiff being denied direct access to the courts. The question was whether Mr Law should be allowed a guardian ad litem to defend the plaintiff’s claim. It was quite inappropriate to require Madam Cheung to satisfy evidential requirements equivalent to those laid down by Part II of the MHO in relation to a process which could result in a third party taking over control of the mentally incapacitated person’s estate.
In the Court of Appeal, the complaint was made that the Judge had misapplied Ho Po Chu v Tung Chee Wah and so had “chosen to adopt a higher standard that is required for other types of inquiry”. However, Cheung JA’s response fails to address the crucial distinction which Yuen JA had emphasised in Ho Po Chu between an adversarial application for a debarring order and the protective appointment of a guardian ad litem under O 80. His Lordship merely stated:
This is not a case where the applicant intervened at an early stage of the proceedings. She only appeared after the judgment had been obtained and enforcement proceedings had been taken. Raising the issue of the defendant’s disability at such a late stage clearly required cogent evidence to be given. In any event, the provision of two experts was agreed to by the parties who were legally represented. I cannot see how the Judge’s decision can be faulted.
E.2 Equating the appointment of a guardian ad litem with exercise of the Court’s paternal and administrative jurisdiction
On 23 April 2013, the Judge handed down a further judgment dealing with the plaintiff’s application for a variation in the costs order and Madam Cheung’s application for leave to appeal. In the course of that judgment, with respect, his Honour appears to have further confused the role of the Court in relation to the appointment of a guardian ad litem in a case like the present, relying on a dictum of Viscount Haldane LC in Scott v Scott. That was a case where the House of Lords was concerned with the question whether the Probate Divorce and Admiralty Court had power to hear a nullity petition in camera, being an issue relevant to deciding whether publication of the details of the hearing by a party constituted a contempt.
It was held that there was no basis for ordering the hearing to be in camera and, in the course of his speech, Viscount Haldane LC contrasted the position regarding in camera hearings obtaining in different courts and contexts, including in the Court of Protection, stating:
The case of wards of Court and lunatics stands on a different footing. There the judge who is administering their affairs, in the exercise of what has been called a paternal jurisdiction delegated to him from the Crown through the Lord Chancellor, is not sitting merely to decide a contested question. His position as an administrator as well as judge may require the application of another and overriding principle to regulate his procedure in the interest of those whose affairs are in his charge.
In order to make my meaning distinct, I will put the proposition in another form. While the broad principle is that the Courts of this country must, as between parties, administer justice in public, this principle is subject to apparent exceptions, such as those to which I have referred. But the exceptions are themselves the outcome of a yet more fundamental principle that the chief object of Courts of justice must be to secure that justice is done. In the two cases of wards of Court and of lunatics the Court is really sitting primarily to guard the interests of the ward or the lunatic. Its jurisdiction is in this respect parental and administrative, and the disposal of controverted questions is an incident only in the jurisdiction. It may often be necessary, in order to attain its primary object, that the Court should exclude the public. The broad principle which ordinarily governs it therefore yields to the paramount duty, which is the care of the ward or the lunatic.
His Lordship was referring to the Court’s paternal and administrative jurisdiction over wards of court and persons then referred to as “lunatics”. Plainly, this has nothing to do with a defendant in ordinary civil proceedings being permitted or required to defend adversarial claims through a guardian ad litem. However, citing the two passages set out above, the Judge erroneously perceived the Court to be exercising the aforesaid jurisdiction, stating:
Therefore, when Madam Cheung made the application pursuant to Order 80, she meant to request that the Court exercise judicial power on the guardianship of the Defendant. The Court has no need to consider whether she has obtained the consent of the Defendant to this application. On the contrary, the Court has to consider and find, under independent medical advice, whether the Defendant can manage his own legal issues, and then determine who would be the most suitable one to be his guardian ad litem if he is found to be a mentally incapacitated person.
The inappropriateness of importing Court of Protection inquiry procedures into O 80 next friend or guardian ad litem decisions was recognized by the English Court of Appeal in Masterman-Lister v Brutton Co (Nos 1 and 2). Kennedy LJ stated:
.... it has to be recognised that someone who is treated as a patient for the purposes of Ord 80, r 1, who litigates by a next friend, is not necessarily and may never become accepted by the Court of Protection as a patient pursuant to section 94(2) of the 1983 Act. As is clear from the wording of section 94(2) the jurisdiction of the Court of Protection is only exercised when, after considering medical evidence, a nominated judge issatisfied as to the person's incapacity. Under Ord 80, r 1 no judicial officer has to consider medical evidence or be satisfied as to incapacity before a person can be treated as a patient.
E.3 Reliance on Ng Hong Ki v Leung Fong Kiu
As I have already pointed out, the present case is one where a judicial inquiry into Mr Law’s mental incapacity was not needed provided the solicitor’s certificate and other documents referred to in Section D above were filed. However, both the Judge and the Court of Appeal considered it necessary to conduct an inquiry, examining the medical and other evidence. They did so relying on the Court of Appeal’s earlier decision in Ng Hong Ki v Leung Fong Kiu and in particular on the following passage in the judgment of Kwan JA:
For the purpose of an appointment of a guardian ad litem under O 80, the test of mental incapacity is ‘issue-specific’ and the test that has to be applied is ‘whether the party to legal proceedings is capable of understanding, with the assistance of such proper explanation from legal advisers .... the issues on which his consent or decision is likely to be necessary in the course of the proceedings’. The focus of the enquiry is on the litigation under consideration rather than the whole of that person's property and affairs. Complete incapacity is not required to be established (Masterman-Lister v Brutton & Co (Nos 1 and 2)  1 WLR 1511, paras18, 27, 62, 75). These features were identified in a person that would lead the Court to conclude that he was a person under disability for the purpose of O 80: ‘.... he had no insight at all into his own mental state. He was not capable of instructing a solicitor properly. He certainly was not capable of exercising any reasonable judgment on a possible settlement.’ (Kirby v Leather  2 QB 367, 384; see also Tang Kam Sheung v Tang Kit Yee (unrep, HCA 677/2007,  HKEC 1599), Carlye Chu J, para 16).
As is apparent, Kwan JA was basing herself essentially on Masterman-Lister v Brutton & Co (Nos 1 and 2), a case in which the Court of Appeal affirmed the need for any inquiry into the alleged patient’s mental incapacity to be “issue-specific”, applying the test “in relation to the particular transaction (its nature and complexity) in respect of which the question whether a party has capacity falls to be decided.” The context of the English Court of Appeal’s decision is therefore important.
Masterman-Lister was a case in which the plaintiff suffered head injuries in a traffic accident in September 1980 and issued a Writ against the defendant in December 1980. In 1987, on the advice of counsel and solicitors, the action was settled for £76,000 plus costs. In 1993 the plaintiff sought, notwithstanding the usual limitation periods,
to re-open the settlement entered into in 1987 and
to sue his former solicitors for negligence.
He could only succeed as to (i) if he was a person under disability when settling the action in 1987 since O 80 r 10 provided that a settlement with such a person was not valid without the approval of the court (which had not been obtained). And he could only succeed as to (ii) if he was shown to be under a disability for the purposes of the Limitation Act 1980 so that time for bringing proceedings was extended. In other words, it was undoubtedly the case that the plaintiff’s mental capacity was being debated in an adversarial context: he was seeking to deprive the original defendant of the benefit and finality of a settlement agreement; and to deprive his former solicitors of a limitation defence. It is therefore unsurprising that he had the burden of showing his mental incapacity after an adversarial judicial inquiry.
Nothing in Masterman-Lister throws doubt on the distinction drawn by Yuen JA in Ho Po Chu v Tung Chee Wah. Indeed, at §66 of Masterman-Lister, Chadwick LJ acknowledged the effect of O 80 r 3 (which was in identical terms to our rule):
Order 80, r 3(2) provided that (save in particular cases) an order appointing a person as next friend or guardian ad litem was not necessary. That, as it seems to me, is of some significance. The rule making body plainly contemplated, and intended, that the question whether a party was required to act through a next friend or guardian ad litem (as the case might be) should, in the ordinary case, be determined by the party himself or by those caring for him; perhaps with the advice of a solicitor but without the need for inquiry by the court. Order 80, r 2(3) required that a next friend or guardian ad litem must act by a solicitor; and rule 3(8)(c)(i) required that, in such a case, the solicitor was to file a certificate certifying that he believed the party to be a patient, with his grounds of belief. But there was no requirement, as such, in the rules for the filing or consideration of medical evidence. If the rule is to work in practice, the test of mental capacity should be such that, in the ordinary case, the need for a next friend or guardian ad litem should be readily recognised by an experienced solicitor.
Kirby v Leather, referred to in the passage from Ng Hong Ki cited above, was likewise a personal injuries case involving the adversarial issue of whether the plaintiff ought to be allowed to start proceedings after expiry of the usual limitation period on the ground that he was under a disability since the date when the cause of action accrued.
The other decision mentioned, Tang Kam Sheung v Tang Kit Yee, was likewise concerned with ascertaining mental capacity in an adversarial situation. The plaintiff, an elderly lady, brought proceedings alleging that the defendant had misappropriated monies belonging to her and was met with a defence (inter alia) questioning her mental capacity to commence and carry on the proceedings on the ground that she was suffering from dementia. The Court was concerned with an attempt by the defendant to obtain a debarring order, staying the proceedings until a next friend was appointed. Chu J accordingly held that, as in Ho Po Chu, such a challenge called for an inquiry into the plaintiff’s mental capacity before denying her direct access to the Court.
It follows that none of the authorities drawn upon by Kwan JA were concerned with the appointment of a guardian ad litem to protect the interests of the defendant in circumstances where no inquiry is needed.
The true focus of Ng Hong Ki lies elsewhere. The plaintiff landlord in that case served notice of termination on the defendant and brought summary judgment proceedings for possession of the premises. The defendant’s brother filed an affirmation on the defendant’s behalf stating that the defendant was suffering from schizophrenia and had been a patient under psychiatric hospital care since 1998. The brother was allowed to make oral submissions to the Master and so was informally treated like a guardian ad litem. As no substantive defence was raised, the Master gave summary judgment for the landlord. On appeal, it was sought to suggest by way of defence that the defendant was not the tenant, but the Judge considered that suggestion incredible and dismissed the appeal. However, he granted the brother’s application to be appointed guardian ad litem, being satisfied on the basis of a medical report that the defendant was a mentally incapacitated person for O 80 purposes.
On appeal to the Court of Appeal, it was sought to be argued on the defendant’s behalf that the Judge should have set aside the order for summary judgment since the proceedings had been conducted without a guardian ad litem and so were in breach of O 80 r 2(1) of the RDC, it being submitted that the substantive steps taken before the appointment of the guardian ad litem were nullities. This was the focus of Kwan JA’s judgment. Her Ladyship was not concerned with deciding whether or on what evidential basis a guardian ad litem should be appointed as one was already in place. Her Ladyship upheld the appointment made by the Judge although he had done so on “scanty” medical evidence. The issue for the Court of Appeal was whether the preceding proceedings were a nullity. Her Ladyship answered in the negative, holding that the Court had power to regularise the position retrospectively. It is in this context that the passage relied on in the Courts below should be placed. It does not provide a basis for supporting the approach adopted below.
E.4 Permitting the plaintiff to oppose appointment of a guardian ad litem for Mr Law
It was, in my view, inappropriate to allow the plaintiff, acting in furtherance of its own interests, to seek to deprive Mr Law, a mentally handicapped person, of the protection of a guardian ad litem, especially since the plaintiff’s success meant that its default judgment would not be challenged on the merits.
I have already quoted Chadwick LJ’s comment that:
.... the question whether a party was required to act through a next friend or guardian ad litem (as the case might be) should, in the ordinary case, be determined by the party himself or by those caring for him; perhaps with the advice of a solicitor but without the need for inquiry by the court.
One might add a fortiori, not determined by the court on the basis of opposition from the other side.
In Folks v Faizey, after referring to the passage just cited, Pill LJ criticised opposition by the respondent to appointment of a litigation friend (or next friend) for the protection of the appellant as “intermeddling for no sound reason”:
In this case, those advising the respondent, without any plausible reason in terms of protecting the respondent's own position, have sought to interfere in a procedure with which they were only minimally concerned. Indeed, the appointment of a litigation friend would give [....] protection to them as well as to the appellant and his advisors. I should not wish to describe the opposition as an abuse of the process of the court but in my judgment it is an intermeddling, for no sound reason, which the judge, on the evidence available, ought not to have tolerated.
The same criticism applies in this case. It would plainly have been appropriate and much fairer to allow Madam Cheung to assume the role of guardian ad litem and then to have her application to set the default judgment aside properly tried. If it was suggested that Mr Law lacked mental capacity to enter into the loan contracts, psychiatric and other evidence bearing on that issue could then be fully canvassed, the “issue-specific” questions then relating to his understanding of the transaction. There is no question of any issue estoppel being raised against the plaintiff in relation to the substantive action merely by reason of a guardian ad litem coming onto the record for the defendant. That is indeed a good reason for the defendant not to “intermeddle”. By taking the course followed in the Courts below, the issue of Mr Law’s mental capacity to enter into the moneylending contracts was never properly reached.
Moreover, it is suggested in the appellant’s printed case (and was suggested in affirmations filed by Madam Cheung) that appointment of a guardian ad litem would enable other possible lines of defence to be explored:
.... it is the Applicant’s position that in addition to the point about the Defendant’s capacity to enter into the Loan Agreement, the Defendant has other arguments to support the application for setting aside the default judgment, eg
There may or may not be substance in these suggestions, but refusing Mr Law a guardian ad litem and dismissing the application to set aside the default judgment meant that those issues have not been aired.
As is often remarked, where a defendant is mentally incapacitated, it is usually in the interests of a plaintiff to be able to deal with a guardian ad litem who is able to ensure that the litigation is properly conducted and to engage in meaningful settlement negotiations. Since settlements by or on behalf of a person under disability are invalid without the Court’s approval, the input of a guardian ad litem in obtaining such approval will generally be crucial.
For the foregoing reasons, I would order that:
the applicant’s appeals be allowed;
the Orders of Deputy District Judge R Yu dated 25 October 2012 (dismissing the applicant’s application to act as guardian ad litem and ordering costs against her) and dated 23 April 2013 in DCCJ 736/2011 and DCMP 2062/2011 (dismissing the applicant’s application for leave to appeal and a stay pending appeal, and ordering costs against her) and the Orders of the Court of Appeal dated 28 January 2014 (dismissing the applicant’s appeal and ordering costs against her) be set aside;
the applicant be appointed guardian ad litem of the defendant and that the applications to set aside the default judgment and consequential orders obtained by the plaintiff against the defendant be restored to the list on a date and subject to such directions as the Registrar of the District Court may determine, with the title of such proceedings amended to refer to the applicant, acting as the defendant’s guardian ad litem;
that there be an order nisi that costs of these appeals, including the applications for leave to appeal, and of the proceedings below referred to in sub-paragraph (b) above be paid by the plaintiff to the applicant, with liberty to the parties to lodge written submissions on the question of costs within 14 days of the date of this judgment and, in default of such submissions, that this order as to costs do stand as an order absolute without further direction.
Justice Tang PJ
I agree with the judgment of Mr Justice Ribeiro PJ.
Justice Fok PJ
I agree with the judgment of Mr Justice Ribeiro PJ.
Justice Stock NPJ
I agree with the judgment of Mr Justice Ribeiro PJ.
Sir Anthony Mason NPJ
I agree with the judgment of Mr Justice Ribeiro PJ.
Justice Ribeiro PJ
The Court unanimously allows the appeal and makes the Orders set out in paragraph 49 above.
 DCCJ 736/2011 (25 October 2012).
 DCMP 2062/2011 (18 October 2011). The aggregate sum owing amounting to $101,754.25 as at that date.
 Now HH Judge R Yu.
 Judgment §9.
 Judgment §13.
 “A person under disability may not bring, or make a claim in, any proceedings except by his next friend and may not acknowledge service, defend, make a counterclaim or intervene in any proceedings, or appear in any proceedings under a judgment or order notice of which has been served on him, except by his guardian ad litem.” All references to Orders and Rules in this judgment are to the Rules of the District Court (“RDC”). They are in the same terms as Order 80 of the Rules of the High Court (Cap 4).
 Judgment §§74 and 75.
 Judgment §79.
 DCMP 2062/2011 and DCCJ 736/2011.
 Cheung, Yuen and Chu JJA, CACV 127 & 128/2013 (17 February 2014).
 With whom the other Judges agreed.
 Court of Appeal §§7.1-14.
 Judgment §23.
 Order 80 r 2.
 Order 80 r 1.
 As appears from the Report of Dr Ng Kee-on dated 25 April 2009, this was the score arrived at using the Weschler Adult Intelligence Scale, Revised Version. The same applies to the Joint Report of Dr Chung See Yuen and Dr Ng Fung Shing dated 17 July 2012 (§35).
 Contrary to the submissions of counsel for the plaintiff, no basis exists for suggesting that there may have been doubts as to whether Mr Law suffered from “deficiencies in adaptive behaviour” for the purposes of the definition of “mental handicap”.
 The exceptions are not presently relevant.
 “.... a person under disability shall not be entitled to appear by his guardian ad litem on the hearing of a petition, summons or motion which, or notice of which, has been served on him, unless and until the documents listed in paragraph (8) have been filed in the Registry.”
 “The documents referred to in paragraph (6) are the following- (a) a written consent to be next friend or guardian ad litem, as the case may be, of the person under disability in the cause or matter in question given by the person proposing to be such friend or guardian; .... (c) .... a certificate made by the solicitor for the person under disability certifying – (i) that he knows or believes, as the case may be, that the person to whom the certificate relates is a minor or a mentally incapacitated person, giving (in the case of a mentally incapacitated person) the grounds of his knowledge or belief; and .... (iii) except where the person named in the certificate as next friend or guardian ad litem, as the case may be, is the Official Solicitor, that the person so named has no interest in the cause or matter in question adverse to that of the person under disability.”
 As recognized in Ho Po Chu v Tung Chee Wah  3 HKLRD 553 at §30.
 Order 80 r 3(4): “Where a person has been or is next friend or guardian ad litem of a person under disability in any proceedings, no other person shall be entitled to act as such friend or guardian, as the case may be, of the person under disability in those proceedings unless the Court makes an order appointing him such friend or guardian in substitution for the person previously acting in that capacity.” (Italics supplied) See Hong Kong Civil Procedure 80/3/10.
 Beall v Smith (1873) LR 9 Ch App 85; Howell v Lewis 65 LT 672; Fry v Fry (1890) 15 PD 50. A challenge as to mental capacity is envisaged in Ho Po Chu v Tung Chee Wah  3 HKLRD 553 at §52.
  3 HKLRD 553.
 At §52.
 MHO section 7(1).
  3 HKLRD 553 at §36.
 Ibid at §39.
 Ibid at §30.
 DCCJ 736/2011 (25 October 2012) at §24.
 Ibid at §§37 to 39.
 Ibid at §26.
 Ibid at §27.
 Court of Appeal at §§22-23.
 And to which, unfortunately, her Ladyship does not appear to have drawn attention in the Court of Appeal below.
 Court of Appeal at §24.
 DCCJ 736/2011 and DCMP 2062/2011.
  AC 417.
 At 437.
 DCCJ 736/2011 and DCMP 2062/2011 (23 April 2013) at §42.
  1 WLR 1511.
 At §12.
  1 HKLRD 435.
 DCCJ 736/2011 (25 October 2012) at §§21, 74 and 75; DCMP 2062/2011 (23 April 2013) at §15. Although the Judge stated that “all parties to the litigation agree” as to the test, Madam Cheung was at the time unrepresented.
 Court of Appeal §7.3, 8-9.
  1 HKLRD 435 at §34.
  1 WLR 1511.
 At §66, per Chadwick LJ.
  2 QB 367.
 Chu J, HCA 677/2007 (25 September 2009).
 At §16. Chu J also considered it potentially necessary to consider proceedings under Part II of the MHO.
 At §35.
 At §§37-40.
 Masterman-Lister v Brutton & Co. (Nos 1 and 2)  1 WLR 1511 at §66.
  EWCA Civ 381.
 At §20.
 At §72.
 Order 80 r 10.
Anson Wong SC, Albert Luk & Billy NP Ma, instructed by Ha & Ho, for the Applicant/Appellant.
Wallace Cheung, Leon Ho, instructed by Philip T.F. Wong & Co., for the Plaintiff/Respondent.
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