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The expert’s role

Chapter number:
Expert Evidence
Last updated:
01 August 2023


22.1 The Tribunal expects expert evidence in asylum and human rights appeals to meet the same general standards as apply in the civil courts. The rules about expert evidence are designed to increase the confidence which a court can place in an expert's opinion. In order to reduce the risk of your expert's opinion being wrongly rejected, it is therefore imperative that you ensure where possible that these standards are met.

22.2 However, asylum and human rights appeals do differ from civil litigation. One of the differences is the esoteric nature of the questions upon which expert evidence may be required. The only person able to give an authoritative opinion upon whether your client could have escaped detention in a particular manner may be a local human rights monitor who deals in life and death issues in a remote part of the country of origin, and who may even place himself at risk by assisting you. If you manage to obtain from him an informal fax that answers your point, that may be more persuasive than a perfectly presented expert report from someone in the UK who has less expertise. One would expect the Tribunal to understand in such circumstances that the reliability of the opinion was consistent with the informality of its presentation. In SSHD v NM and KY (Somalia) [2014] UKSC 30, Lord Carnwath noted that:

34 ... The practice directions contain valuable guidance on the general principles applying to expert evidence. To a large extent they follow the principles applicable in civil courts, designed (inter alia) to ensure that the expert provides truly independent assistance to the tribunal, does not assume the role of advocate, and sets out the facts and other material on which an opinion is based. ...As Lord Eassie acknowledged, the practice directions did not have to be rigidly applied.

35 In the civil courts, flexibility on such matters is routinely accepted under modern practice. For example, in Rogers v Hoyle (Secretary of State for Transport and International Air Transport Association intervening) [2014] EWCA Civ 257, the Court of Appeal confirmed the admission of a report by a body known as the Air Accident Investigation Branch, one objection having been that it failed to comply with mandatory rules (CPR Pt 35) relating to expert evidence. In support of a flexible approach to the rules, Christopher Clarke LJ at para 44 cited (inter alia) Sunley Gowland v White (Surveyors and Estate Agents) Ltd [2004] PNLR 257, in which

"this court regarded as admissible a draft soil report issued by a B company although the report was unsigned, provisional and did not carry the name or qualifications of the author. These were matters which Clarke LJ, with whom Longmore LJ agreed, treated as 'essentially going to weight'."

36 Such considerations apply with equal or greater force before tribunals

22.2A Similarly, in HK (Iraq) & Ors [2017] EWCA Civ 1871, while holding that a report from Amnesty International could not be treated as an expert report because it did not comply with the requirements of the Civil Procedure Rules for expert evidence, the Court of Appeal observed that:

It is relevant to add that both a court and a tribunal have extensive case-management powers which would enable them to dispense with all or some aspects of the rules under CPR Part 35 and section 10 of the Tribunal Practice Direction. For instance, expert evidence which comprises the views of a number of experts might be admitted in an appropriate case and where there is no unfairness involved: see MN (Somalia) v Secretary of State for the Home Department [2014] UKSC 30; [2014] 1 WLR 2064, [43] per Lord Carnwath JSC (with whom the other Justices agreed). However, if a court or a tribunal is to be asked to do this, it should be appreciated that it will have regard to the overriding objective to deal with cases justly and at proportionate cost. The party applying for dispensation from the usual rules governing admission of expert evidence will need to show good reason why that course should be taken and the court or tribunal will be concerned to ensure that this will involve no unfairness to the opposing party.

22.2B In PP (female headed household; expert duties) Sri Lanka [2017] UKUT 00117 (IAC), while criticising the experts (and those instructing them) for failing to comply with the requirements for expert evidence in their written reports, the Tribunal nonetheless accepted that the witnesses were experts, admitted their evidence, and gave it weight.

22.3 On the other hand - and contrary to what is sometimes supposed - the fact that it is an asylum and human rights appeal rather than a civil case does not excuse the presentation of a similarly informal fax when the expert is an established UK academic. Most commonly, expert evidence contravenes the rules about expert evidence not through necessity, but because of lack of awareness on the part of the expert as to what is required flowing from lack of awareness on the part of the representative. In PP (Sri Lanka) [2017] UKUT 00117 (IAC), the Tribunal felt that primary responsibility for the multiple defects in the expert evidence lay with the appellants' representatives who did not appear to have drawn their attention to the guidance discussed below (para 27); see also R (on the application of Hoxha and Others) v Secretary of State for the Home Department (representatives: professional duties) [2019] UKUT 00124 (IAC). See chapter 23 for further discussion of your responsibilities in respect of expert evidence.

22.4 Unless the expert's circumstances render it inappropriate or impractical to follow the ordinary rules applicable to expert evidence, the gravity of the issues in asylum and human rights appeals renders it more rather than less important that these rules are complied with. The effect of compliance ought to be to increase a court's confidence in your expert evidence, and therefore to reduce the risk of a wrong decision.

22.5 Unless you are instructing an expert who is trained or experienced in providing expert evidence for litigation, he will need guidance as to what the court requires from an expert. He cannot be expected to guess this, yet ignorance of the rules governing expert evidence can result in wholly avoidable criticism of your expert by the Tribunal. During the three month hearing of the asylum appeals of the victims of the Afghan aircraft hijacking, Home Office counsel cross-examined the appellants' expert on whether he was aware of the rules governing expert evidence laid down in the Ikarian Reefer (National Justice Compania Naviera S.A. v Prudential Assurance Co. Ltd) [1993] 2 Lloyds Rep 68. The Tribunal will similarly expect an expert to be aware of these duties (see e.g. MOJ and Others (Return to Mogadishu) Somalia CG [2014] UKUT 00442 (IAC), at [23] – [27], MS (Trafficking – Tribunal's Powers – Art. 4 ECHR) Pakistan [2016] UKUT 00226 (IAC) and AAW (expert evidence – weight) Somalia [2015] UKUT 00673 (IAC)) and of the duties in the Practice Direction. In AAW (expert evidence – weight) Somalia [2015] UKUT 00673 (IAC), the Upper Tribunal made clear that a failure to comply with the Practice Direction will affect the weight to be given to an expert's report (see also PP (female headed household; expert duties) Sri Lanka [2017] UKUT 00117 (IAC)).

22.6 Much of this guidance is of general application and can be recycled whenever you instruct a new expert. (If you cannot produce your own guidance covering the following points, you could even provide the expert with this chapter.) You should always provide an expert with the relevant extract from the Tribunal's Practice Direction and the Upper Tribunal has said that it expects experts to be provided with a copy of the guidance at paragraphs 23-27 of MOJ and Others (Return to Mogadishu) Somalia CG [2014] UKUT 00442 (IAC) as a matter of course in every case: see MS (Trafficking – Tribunal's Powers – Art. 4 ECHR) Pakistan [2016] UKUT 00226 (IAC).

The role of the expert and his duty to the court

22.7 Unless your expert is familiar with the asylum appellate process, you should start by explaining to him what is going on. An expert may not even realise that his evidence will be considered at an adversarial hearing. This is not only a courtesy to the expert, but should mean you get a better report due to his better understanding of his role and what is expected of him. You may want to refer him to the Best Practice Guide to Expert country evidence in asylum and immigration cases in the United Kingdom, by Professor Anthony Good and Dr Tobias Kelly of the University of Edinburgh.

22.8-22.12 […]

22.13 In MOJ and Others (Return to Mogadishu) Somalia CG [2014] UKUT 00442 (IAC), the Upper Tribunal summarised these duties in the following terms:

(i) to provide information and express opinions independently, uninfluenced by the litigation;

(ii) to consider all material facts, including those which might detract from the expert witness' opinion ;

(iii) to be objective and unbiased;

(iv) to avoid trespass into the prohibited territory of advocacy;

(v) to be fully informed;

(vi) to act within the confines of the witness's area of expertise; and

(vii) to modify, or abandon one's view, where appropriate.

The boundaries of expert opinion

22.14 This matter consistently troubles the Tribunal. It is central to the practical presentation of expert evidence, but it is impossible to deal with it effectively (both advising the expert and rebutting objections to his evidence) without some consideration of the relevant legal issues.

22.15 You may hear it claimed that an expert's opinion infringes the 'ultimate issue rule'. This 'rule' was developed by the courts from the 18th Century. It was said to prohibit an expert from expressing an opinion on an issue which the court would ultimately be called upon to decide - the rationale was that an expert must not usurp the role of the Court as ultimate decision maker. It has been described as 'a mere bit of empty rhetoric' (Evidence (Chadbourn rev) para 1920) since a court is always free to disagree with the expert (provided its decision is open to it on the evidence as a whole). Its application has been described by the Court of Appeal (R v Stockwell (1993) 97 Cr App R 260) as 'vexed'. It is not hard to see why. Plainly, the court will have to reach a conclusion on all issues which are pertinent to the case. And an expert might be forgiven for thinking that his usefulness in the case rests upon the degree to which he can proffer expert opinion upon the most pertinent issues.

22.16 You may still on occasion find the 'rule' being invoked by HOPOs to dispute the admissibility of a particular expert opinion. It is useful, therefore, to point out that it was actually abolished in civil proceedings by the Civil Evidence Act 1972 (M and R [1996] 4 All ER 239). Although that Act did not apply to criminal proceedings, the Criminal Division of the Court of Appeal has effectively abandoned it. In Stockwell (1993) 97 Cr App R 260, Lord Taylor LCJ said that:

The rationale behind the supposed prohibition is that the expert should not usurp the functions of the jury. But since counsel can bring the witness so close to opining on the ultimate issue that the inference as to his view is obvious, the rule can only be... a matter of form rather than substance. In our view, an expert is called to give his opinion and he should be allowed to do so. It is, however, important that the Judge should make clear to the jury that they are not bound by the expert's opinion, and that the issue is for them to decide.

22.17 This does not, however, mean that the expert is entitled to relay any opinion that he has formed on the case or your client. The additional scope it gives the expert to comment renders it all the more important that he understands and respects the limits of his expertise. But it does enable the expert to focus, unencumbered by technicalities, on the real test: does he possesses expertise on the issue beyond what may be expected from the court?

22.18 This test does not (any more than the ultimate issue rule would have done) entitle him to offer an opinion on whether someone is a refugee. His expertise may extend across a range of factual issues by which it is determined who the appellant is, what happened to him in the past, and what may happen to him in the future. But after all these factual issues are resolved, there remains the task of applying the legal standard to those findings of fact. As the Tribunal has pointed out, it remains the judge's 'duty to test and evaluate the evidence in accordance with the legal criteria contained in the 1951 Refugee Convention. An expert is not a judicial decision-maker' (Gomez v SSHD (00/TH/02257)).

22.19 That principle applies equally to constituent elements of the legal definition. The expert should not offer a conclusion on whether the treatment your client faces amounts to 'persecution' (or in an article 3 case, whether it amounts to 'inhuman or degrading treatment'). Determining what factual events will or might occur is only the first stage in answering this question. The second stage is applying to that factual assessment legal standards which are dependent upon an understanding of refugee and human rights caselaw. The expert may well possess expertise beyond that of the court in conducting the first stage, the factual assessment. However, he should strive to convey all the opinions that his expertise permits without trespassing upon the second stage of applying the legal standard.

22.20 The distinction is not always straightforward to apply. Whether a claimant has a 'well-founded fear' of a particular event occurring depends on whether there is in fact a 'real risk' that it will happen. (The same 'real risk' threshold applies to article 3 claims.) So this issue is a constituent part of the test both for refugee status and article 3 protection. However, the probability that a particular event will occur in the country of origin in a given scenario is a matter which may well call for expert evidence. What needs to be determined is whether there is a real risk that it shall occur - an ordinary English phrase. Asking the expert to use a different formula in expressing his opinion simply through fear of treading on the court's toes is liable only to obfuscate his evidence on the question. The expert's opinion in this regard does not of course prevent the Tribunal from reaching a different opinion as to whether there is a real risk, including by reference to the caselaw interpreting and applying that term in the particular legal context. As the Supreme Court put it in Kennedy v Cordia (Services) LLP [2016] UKSC 6 (which gave much guidance on expert evidence of direct relevance to asylum and human rights appeals):

…while on occasion in order to avoid elusive language the skilled witness may have to express his or her views in a way that addresses the ultimate issue before the court, expert assistance does not extend to supplanting the court as the decision-maker. The fact-finding judge cannot delegate the decision-making role to the expert.

22.21 What distinguishes the issue 'is there a real risk that x will happen' from the issue 'does x constitute persecution' is that upon the former it is not possible - or useful - to draw a clear division between the assessment for which the expert may draw upon special expertise and the conclusion upon the legal test which the court must apply.

22.22 Another example is whether prison conditions meet international standards. To some extent, this involves applying legal standards found in international human rights law, but it involves other factors as well and is a test, for example, which the US State Department routinely applies in its country reports. Where your expert is a human rights monitor, it will not therefore be inappropriate to express an opinion on the question.

22.23 Similar scenarios arise in other jurisdictions. Even prior to the abandonment of the 'ultimate issue rule', experts in the criminal courts were regularly permitted to pronounce upon whether or not the defendant was suffering from 'diminished responsibility' - even though that was the final question for the court (DPP v A and B Chewing Gum [1968] 1 QB 159). The modern view, as appears from Stockwell (1993) 97 Cr App R 260, is that so long as the court remembers that the final decision is for it, 'the expert is called to give his opinion and should be allowed to do so.' In Pora v R [2015] UKPC 9, the Privy Council emphasised that:

It is the duty of an expert witness to provide material on which a court can form its own conclusions on relevant issues. On occasions that may involve the witness expressing an opinion about whether, for instance an individual suffered from a particular condition or vulnerability. The expert witness should be careful to recognise, however, the need to avoid supplanting the court's role as the ultimate decision-maker on matters that are central to the outcome of the case

22.24 The expert ought then to go as far as necessary - but no further - in order to provide the court with such assistance as his expertise qualifies him to give. The expert should ask at each stage 'In expressing this opinion, am I drawing upon expertise that the court cannot be expected to possess?'

22.25 That analysis also assists in addressing the particularly problematic issue of the extent to which an expert is entitled to offer an opinion relating to the appellant's credibility.

22.26 Traditionally, courts have held that whether or not a witness is telling the truth is a question upon which expert evidence will not be entertained. The justification was both that it would usurp the function of the court (in other words, the ultimate issue rule) and that the task was within ordinary experience so that no expert evidence was required. The courts were particularly concerned to ensure that a jury was left to determine credibility for itself.

22.27 Yet even in the criminal courts, barriers are now breaking down and psychiatric evidence relating to credibility (e.g. reliability of confessions) is increasingly admitted which would not have been admitted in the past. That is especially so where credibility is affected by issues such as age and mental condition which are outside the ordinary experience of a jury made up of ordinary adults. The same test applies: whether the opinion is based on expertise outside the ordinary experience of the court.

22.28 Both the Court of Appeal (para 19.5) and the Tribunal (para 1.5) have recognised that this will very often be the case in this jurisdiction where evidence comes from persons of very different cultures. The ordinary experiences of the refugee are also happily remote from those of a judge who is unlikely to have endured the effects upon the mind of persecution and flight.

22.29 That said, the expert should normally be able to convey his expert opinion without expressing a direct opinion on the appellant's honesty. Expert evidence may be eminently appropriate to rebut allegations about the plausibility of the appellant's account and to expose associated cultural misconceptions. The expert may conclude that something is plausible in light of conditions in the country of origin, and consistent with or explicable by cultural or mental factors. But the court considers it important to distinguish between such expert opinions and the further step of reaching a conclusion that the witness is credible (see further para 26.45 as to the role of a medical expert in expressing a view as to consistency with an account of torture, as distinct from whether or not he "believes" the appellant).

22.30 If an allegation of implausibility is the only basis upon which the account is questioned, then the inference to be drawn from rebuttal of that allegation will be clear. But it is still important that the expert leaves that inference for the court - that he goes no further than he must in order to convey his expertise. Such has been the concern in the Tribunal about experts overstepping the mark in this regard - and the connotations that the term 'credibility' has in this jurisdiction - that your expert will be wise to avoid the word altogether when commenting on such issues. (Without this advice, the expert may think he is acting perfectly within his expertise in concluding in the light of his own knowledge and expertise that an account is 'credible'.) The Court of Appeal's judgment in MF (Albania) v SSHD [2014] EWCA Civ 902 illustrates the dangers of inviting an expert to respond directly to arguments in the refusal letter. Moore-Bick LJ considered that this had led her to offer opinions beyond those that were justified by her expertise and "In effect, she ceased to act as an expert witness and took on the role of an advocate" (para 16).

22.31 There will be cases where it is idle to pretend that the expert is not offering a direct opinion on whether the appellant is telling the truth. A prime example is where nationality or ethnicity is in dispute. A judge is highly unlikely to have the expertise to resolve this based on questioning or observation. Typically therefore, an expert will interview the appellant and form a view based upon some combination of his answers, his language and dialect, and his appearance as to whether his claimed nationality or ethnicity is genuine. That is not objectionable, even where (as was the case in the past for Kosovan Albanian claimants) the conclusion is effectively determinative of the appeal. Indeed, the expert's input is particularly vital where mistakes on such issues can lead to refoulement. However, in SSHD v MN & KY (Somalia) [2014] UKSC 30, the Supreme Court was critical of the Sprakab analysts for expressing a view as to the manner in which the asylum seekers had answered questions about their nationality and home areas, and particularly of the comment that answers given by MN "sounded rehearsed", which it did not consider to be a matter for expert - or even witness - evidence at all. Their observations should have been limited - if they had the necessary expertise - to noting areas where the applicants lacked knowledge, or gave incorrect answers.

22.31A The Tribunal has also held that it is inappropriate for an expert to offer an opinion on how the appellant will behave on return to her country of origin (SW (lesbians – HJ and HT applied) Jamaica CG [2011] UKUT 251 (IAC), para 97). However, there may be some circumstances in which this is a matter on which it is appropriate for your expert to comment, such as where this might be influenced by cultural considerations. His comments should however be limited to how a person such as the appellant might be expected to behave, rather than how the appellant actually will.

22.32 In Mibanga v SSHD [2005] EWCA Civ 367, Wilson J (in a unanimous judgment) explained the duty to have regard to relevant expert evidence as an integral part of reaching a credibility finding, without the expert usurping the fact-finder's function:

24. It seems to me to be axiomatic that a fact-finder must not reach his or her conclusion before surveying all the evidence relevant thereto. Just as, if I may take a banal if alliterative example, one cannot make a cake with only one ingredient, so also frequently one cannot make a case, in the sense of establishing its truth, otherwise than by combination of a number of pieces of evidence... [T]he Secretary of State, argues that decisions as to the credibility of an account are to be taken by the judicial fact-finder and that, in their reports, experts, whether in relation to medical matters or in relation to in-country circumstances, cannot usurp the fact-finder's function in assessing credibility. I agree. What, however, they can offer, is a factual context in which it may be necessary for the fact-finder to survey the allegations placed before him; and such context may prove a crucial aid to the decision whether or not to accept the truth of them. What the fact-finder does at his peril is to reach a conclusion by reference only to the appellant's evidence and then, if it be negative, to ask whether the conclusion should be shifted by the expert evidence.

22.32A The relevance of expert evidence to the assessment of plausibility is demonstrated by the evidence in that case. Wilson J observed that the judge's 'findings have cumulatively to be surveyed and then contrasted with the views of the professor' and analysed the findings as follows:

(a) The adjudicator found that the appellant's account of his second escape/release was wholly not credible. The professor, however, had offered a view that the reasons why he had been enabled to escape on this second occasion were very plausible. Although I have already accepted that issues of credibility were for the adjudicator, it was relevant for the professor to point out (as, notwithstanding the submissions of Mr Tam, I construe him to have done) that this second escape indeed occurred at the time of riots; and that the appellant and the alleged guard were members of a tribe which was not affiliated with the Mai-Mai and which had no particular sympathy with it. It was, to put it mildly, bold of the adjudicator to say that, notwithstanding the professor's view, the appellant's account of this incident was wholly not credible; and it seems to me that, although she had in principle the right so to do, she had to venture a reason not just for rejecting his view but indeed for placing it outside the spectrum of rational views.

(b) The adjudicator also found it wholly not credible that the appellant's wife would have been permitted to visit him in prison and in hospital. She did admittedly remind herself that her conclusion in this respect differed from that of the professor, who had, without qualification, stated that RCD-Goma allowed families to visit detainees. If he was thereby making a statement directly inconsistent with any of the other, objective material before her, the adjudicator has not identified it. Again in my view she owed the appellant a reason for finding that his expert's view was beyond the pale of credible views.

(c) The adjudicator's conclusion that the appellant's account of being detained and tortured for almost three years was incredible also ran wholly counter to the professor's view that his account of detention and torture was believable. I am yet again perplexed that the adjudicator, who of course did not need to express herself in such vivid terms, felt able to sideline the professor's view in this regard as worthless; and, as before, it seems to me that a proper fact-finding enquiry involves explanation as to the reason for which an expert view is rejected and indeed placed beyond the spectrum of views which could reasonably be held.