by Mark Henderson and Rowena Moffatt of Doughty Street Chambers
and Alison Pickup of the Public Law Project
~ Revised 2021 Edition ~
Whether to call oral expert evidence
Preparation for the hearing
The Hearing. Examination in chief
25.1 The Tribunal has indicated that it particularly values oral evidence from experts. It considers that the discipline imposed by oral examination is an important check upon the reliability of their evidence. It is now common practice for experts to give oral evidence in Country Guidance cases and the Tribunal encourages this. In VH (Call Witnesses) Moldova  UKIAT 00325 (para 40), the Tribunal said that 'When parties realise that the Tribunal may be considering giving country guidance, they should think very carefully about applying to call oral evidence as it will be the kind of case where the Tribunal may be assisted by hearing oral evidence properly tested by cross-examination.' In LZ (homosexuals) Zimbabwe CG  UKUT 00487 (IAC), the Tribunal commented that it found it "strange that an expert should be unwilling to have her evidence and opinions tested at a hearing" where one of the experts had agreed to provide a report only on condition that she not be called to give oral evidence and for that reason together with the unanswered questions it left about her report, the Tribunal made clear that her evidence 'played no significant part in reaching our conclusions' (para 62).
25.2 For other cases, there are particular features of asylum and human rights appeals that often render oral expert evidence impractical. There may be a very small number of suitably qualified experts on a country which is presently generating a large number of appeals. It may not be practical even to obtain a written report on every appeal, still less have the expert give oral evidence at each hearing. Expert evidence may have to be sought from abroad, in which case attendance at the hearing may be ruled out by impracticality or cost.
25.3 This has been recognised by the Court of Appeal. In Tarlochan Singh v SSHD  EWCA Civ 1773, the Court considered a decision of the IAT in which it had rejected an expert report because the expert had not been available for cross-examination. Buxton LJ said that the author had been
put forward as an expert, just as the authors of all the other [human rights] documents before the tribunal were put forward as experts. In the way in which this sort of inquiry is necessarily conducted in front of a tribunal, it is only rarely going to be the case that evidence is given by persons actually appearing in front of a tribunal rather than by reference to the reports of persons of greater or lesser weight - Amnesty International, the United Nations Commission on Refugees and the Canadian body used in this case. It was, therefore, not sufficient simply to reject [the expert's evidence] because he had not been cross-examined.
25.4 If the HOPO seeks to criticise the fact that an expert is not available for oral examination, you may also wish to point out that the Home Office urges reliance upon its country reports despite never offering the authors for cross-examination.
25.6 Obviously, the ideal is that you seek to reach agreement on the expert evidence with the Home Office in advance. Unfortunately, you may come up against a brick wall attempting to engage the Home Office in useful discussion prior to the hearing. The result is wasted time and expense. Consider therefore seeking a direction that the Home Office indicates whether, and on what grounds, the expert report is disputed (para 23.45). However, the Tribunal has held that so long as the Home Office has been served with an expert report well in advance of a hearing; has not served any expert evidence of her own; and has not indicated before the hearing that she would wish to question the expert, the fact that the expert does not give oral evidence will not be such as to undermine the weight to be attached to the expert's report (Cudjoe (Proxy marriages: burden of proof)  UKUT 00180 (IAC)).
25.7 Where you are lucky enough to be able to agree expert evidence in advance, the expert's attendance at the hearing should not be necessary. The Tribunal should not go behind such an agreement (Carcabuk & Bla v SSHD (00/TH/01426)). If unforeseen issues subsequently arise at the hearing upon which the expert's comment is needed, it will normally be unfair to refuse an adjournment for that purpose.
25.8 If expert evidence is not agreed, then although not obligatory, the benefits of calling your expert are several. As indicated above, particularly in Country Guidance cases, the Tribunal often prefers to hear from experts. Where a judge might otherwise be minded to reject an expert's opinion, the expert's ability to respond to cross- examination and the judge's questions may persuade him otherwise. The Tribunal has on occasion changed its view of an expert after hearing oral evidence even where previous written reports had been rejected in strong terms (see, for example, SW (Jamaica) CG  UKUT 251 (IAC)).
25.9 The expert's presence will invariably focus the judge's mind on his evidence. (Sometimes, a judge fails to deal with an expert report at all in his determination, often necessitating an appeal.) Unless your expert presents badly, the judge is less likely to be dismissive of an expert who appears before him. Equally, the HOPO is likely to feel more inhibited from making unjustified allegations against the expert, particularly if the expert has dealt with the HOPO's cross-examination satisfactorily. Indeed, some suspect that the very sight of the expert attending for cross-examination has influenced an unexpected settlement offer from the HOPO at the door of the court.
25.10 If your expert's evidence is nonetheless rejected, the fact that he dealt with whatever points were put to him in examination may well strengthen any appeal. It will be even less justifiable for a judge to reject expert evidence on a point which has not been raised at the hearing if the judge and HOPO had ample opportunity to put the point to the expert. (And see conversely the IAT's comment in Kapela v SSHD  Imm AR 294 that the risk of not calling the expert is that the judge is left with unanswered questions.)
25.11 Last but not least, if an unexpected issue arises during examination of the appellant or other witnesses, your expert will be there to comment on it. Similarly, where oral evidence departs from or adds to that contained in the witness statements, your expert will have seen that evidence and can say whether or not his opinion has altered. The HOPO cannot then seek to undermine the expert's opinion on the basis that it was reached in ignorance of the oral evidence.
25.12 Prior to making a final decision about whether or not to call oral expert evidence, there obviously has to be an assessment of how good a witness the expert will be. Indeed, where there is a choice of suitably qualified experts, this assessment may influence who to instruct. An expert may write thorough and reliable reports but be poor at performing in court.
25.13 You need to know how the expert will handle cross-examination. The best way to establish this is to ask some probing questions yourself. You should therefore see the expert, or at least have a substantial telephone conference, prior to deciding that he should give oral evidence.
25.14 If your expert is not going to give oral evidence, it is all the more important that you invite, and if necessary seek a direction that the Home Office either agrees the expert report or indicates what parts are disputed and on what grounds. You should also invite the Home Office to provide any written questions for your expert's consideration (a procedure which is formalised in the CPR). All these steps will render it less likely that the expert's opinion can be dismissed on grounds that he has not had an opportunity to rebut, or because he does not attend the hearing to give oral evidence (see Cudjoe  UKUT 00180 (IAC), above). But these steps can only happen if your expert is instructed, and his report prepared and served, in good time.
25.15 A further reason for deciding at the earliest possible stage whether your expert will give oral evidence is in order to check his availability and make any application to the Tribunal concerning listing. Where an expert's evidence is prima facie relevant and an adequate reason is given for his unavailability on the date listed, there will be 'every ground' for granting an adjournment: SSHD v Kondo (10413). It is important that you inform the Tribunal as soon as you are aware that there may be a problem with the expert's attendance.
25.16 You will normally be asked at the CMRH, or when sending a reply for a paper PHR, about your intentions with regard to expert evidence. If you hope to call oral evidence but are not sure yet of your expert's availability, ask the Tribunal to note this on the record as you may otherwise be criticised for the timing of a further adjournment request. If you have not yet finalised instruction of an expert, explain to the court why expert evidence is important, what steps have already been taken to obtain it, what further steps you plan to take, and an estimate of how long this will take. (You must be able to offer a date on which you should be ready to proceed; see also para 6.13.)
25.17 The possibility that your expert might be prepared to give evidence only on condition of anonymity was raised at para 21.21. If so, consider an application either that the public be excluded from the hearing, that the expert not be required to give oral evidence that may identify himself, and/or publication of his identity be prohibited (see chapter 32).
25.18 It would of course be possible to seek a witness summons in respect of your expert were he otherwise unwilling or unable to attend (though only if he is within the UK). But you should hesitate long before summonsing an expert (or any witness) against his will. It might be appropriate to obtain a summons where the expert himself was happy to appear but was being prevented from doing so, say, by his employer.
25.19 The IAT in Zarour v SSHD (01/BH/00078) said that it would have been prepared to issue a witness summons of its own motion against an expert whose report was in evidence before them. That possibility should be borne in mind. However, the Court of Appeal has indicated that the power of the IAT to summons a witness should be exercised sparingly (para 9.45). The IAT also held in SSHD v Prendi (01/LS/00060) that a judge should not issue a witness summons of his own motion simply to enable the HOPO to cross-examine a witness (which the HOPO could not do if he applied for the witness summons himself) - see para 30.15.
25.20 It is most important that you have a full conference with your expert prior to his appearance in court, although in some cases it will be sufficient for this to be performed by telephone. The conference should not, unless unavoidable, take place on the day of the hearing. You should allow sufficient time for the expert to make any further enquiries or conduct any further research arising out of the conference. He may at least want some further period to reconsider the documentation in light of the potential challenges to his evidence which are discussed. If he is unused to giving evidence, he will also appreciate being briefed on what to expect well before he reaches the doors of the court. The conference should, if at all possible, be conducted by the advocate who will present the hearing.
25.21 Experts in other jurisdictions commonly receive training in presenting expert evidence to a court, including cross-examination, and have substantial experience of it in practice. It is far less common in this jurisdiction (largely on grounds of cost). Before discussing case-specific issues you should explain in some detail how an appeal hearing is conducted. When you are so familiar with the process, it is easy to forget how ill at ease your expert may feel at the prospect of entering and performing in an environment of which he knows next to nothing. Putting him at ease, even on simple things like how to address the judge, leaves him free to concentrate on the contents of his evidence.
25.22 You should also give general advice about presentation of oral evidence: listen to the question but direct the answer to the judge; speak clearly and pause sufficiently to allow the judge to take a note; consider carefully (and with an open mind) any proposition that is put to him by the HOPO and (particularly) the judge; avoid emotive language or appearing partisan.
25.23 He should give his evidence in a calm and straightforward manner (especially under aggressive cross-examination) and should avoid appearing on the one hand nervous or uncertain, and on the other hand arrogant or over-confident. Where a proposition is repeatedly put with which he does not agree, he should express his disagreement calmly and firmly but having explained his response, avoid being drawn into an argument. If he realises that one of his earlier statements requires revision, then he should say so and explain why. He should say if he does not know the answer to the question or if he considers that he is being asked to comment on a question outside his remit.
25.24 In accordance with the practice as to witness statements, your expert's written report will stand as his evidence in chief. This means that oral examination in chief may be limited. Cross-examination may well be the primary environment in which the Tribunal is able to assess the expert's oral evidence. It is imperative that any witness listens to the question and shows how he is answering it. But if your expert is confident and capable of doing so properly, he can also be advised to use the questions as a hook to advance relevant and important points to the Tribunal, rather than following the common advice on cross-examination of saying as little as possible consistent with answering the question.
25.25 It is your job to foresee lines of cross-examination. You ought to know what his views will be on any topic about which he is likely to be cross-examined. Apart from forewarning you of any problems which can be pre-empted in evidence in chief, it is a prerequisite to conducting an effective re-examination.
25.26 The aims of cross-examination might be to persuade the expert to accept points favourable to the Home Office; to probe his knowledge by asking him about matters contained in the country reports; to portray his opinion as unbalanced when compared to the country reports; to suggest that he has insufficient evidence to justify his opinions; and to allege inconsistency between the expert's opinion and the actions or opinions of the appellant so as to support credibility challenges. An example of the latter would be where your expert is encouraged to agree that the appellant would have been in great danger during a particular period, from which the HOPO alleges that it is not credible that she did not try to escape earlier.
25.27 The passages at paras 23.26 - 23.44 on preparing a written report for disclosure apply equally to discussing the expert's oral evidence. You can and should tell the expert if the answers he gives are unclear, or seek further information if his answers appear unconvincing, and you may put points to him that he may have overlooked. But this process must not trespass into 'coaching' or place him under any pressure to alter his opinion.
25.28 His oral evidence is not a memory test. He should familiarise himself with his written report before the hearing. He should bring with him to the hearing all the documentation that he has been given (and his report). If he has not already been provided with the paginated bundle that is being used by the Tribunal, then he should be given the full bundle in the form that it was provided to the Tribunal, in time to familiarise himself with it (NOT when he arrives at the hearing), including any skeleton argument served by you. If he was not referred to the Home Office's country reports when preparing his report, he should be asked to consider it now as the HOPO may cross-examine him about that material as well as any other country material before the court.
25.29 The above discussion assumes that the expert report was prepared according to the best practice set out in the previous chapters. If an expert report was disclosed before you were instructed, that may not be the case and the report itself may be problematic. If so, a conference is all the more important, and an important part of the conference will be exploring what can be done to address the deficiencies in the original report through oral evidence or (preferably, if there is time) a supplementary report.
Sometimes - through lack of guidance as much as any fault on his part - the report may be so flawed that it will be better to instruct another expert rather than attempt to retrieve the position through further evidence from the report's author.
25.29A Note however in relation to any report that has been lodged in support of the appeal, the Practice Directions (para 10.7) state that 'If, after producing a report, an expert changes his or her view on any material matter, that change of view should be communicated to the parties without delay, and when appropriate to the Tribunal.' Therefore, if there has been a significant change in the expert's view (particularly one which may appear adverse to your case) you are required to notify the Home Office and the Tribunal in advance of the hearing. Indicating the change only at the beginning of an expert's evidence in chief may be viewed as insufficient to comply with the Practice Directions.
25.30 The expert should normally give evidence after all witnesses of fact and should be present to hear the evidence. Unlike a witness of fact, an expert's primary purpose is to give his opinion upon the factual evidence. This has to be explained to some HOPOs who, unused to expert witnesses, may wrongly suggest that the expert be excluded from the hearing until he gives evidence.
25.31 You should check with the judge before you start examination in chief whether he has read the expert report and if not, invite him to do so before the expert is called. Your oral examination in chief should start by asking the expert whether he has modified any of the opinions in his report and if not, to confirm that he adopts the views contained therein (But see para 25.29A above.) You may also wish to confirm whether he has met the appellant (other than at the court).
25.32 If there is nothing further upon which you want him to comment or elaborate, that is sufficient examination in chief. As with witnesses of fact, it can be effective simply to offer him for cross-examination immediately (which also sometimes discomforts the HOPO).
25.33 The potential drawbacks of this approach are twofold. Firstly, like other witnesses, if this is the first time the expert has given oral evidence, he should ideally have an opportunity to get into his stride by dealing with a couple of questions of which he has had advanced warning.
25.34 Secondly, the cross-examination may not be sufficiently relevant or extensive to allow the expert a full opportunity to impress his expertise upon the judge through his oral presentation. The problem is exacerbated if the judge does not have a clear recollection of the expert's written report when he hears the evidence. You may therefore decide to prepare a couple of questions which will give the expert an opportunity to demonstrate his expertise by expanding on the opinions in his report. But avoid inviting the objection that he is simply being asked to repeat information in his report (an objection that should not arise so long as your evidence in chief remains short and focused).
• if developments have taken place in the country of origin which post-date the expert's report;
• if new issues have arisen during the hearing upon which he can give expert comment, such as a new allegation about implausibility or risk during the HOPO's cross-examination of the appellant.
• Where this is the case, you should, if necessary, request a short adjournment in order to discuss the point with your expert before he gives evidence.
• if there are problems with the written report which need to be remedied (but see para 25.29A above), or it does not deal with all the matters upon which the expert can give relevant evidence.
25.36 A similar dilemma may arise as with witnesses of fact: whether to deal with a potential problem in examination in chief or whether this simply draws unnecessary attention to it. Where there is a real risk that the problem will emerge later, whether in cross-examination or on the judge's initiative, it is usually best to get it over with in examination in chief. If the expert's opinion has altered from that contained in the written report, you have, of course, no option but to raise it if it has not already been raised in accordance with the Practice Directions (see para 25.29A above).
25.37 That approach is also consistent with the expert's over-riding duty to the court. It may actually assist the expert's credibility by impressing upon the judge that he is taking this duty seriously and is anxious to be entirely straightforward. It may be much more damaging if such problems emerge only in cross-examination. However as with witnesses of fact, there is no need to dwell on issues which only a HOPO might suggest were problematic so that your examination in chief starts to resemble the HOPO's cross-examination.
25.38 The better a witness the expert is, the more general the questions can be, allowing the expert to develop his evidence himself. If your expert is more uncertain, the questions should be more specific so as to guide the expert away from repetition or irrelevance (though the normal rule prohibiting leading questions applies).
25.39 In any event, you ought to give your expert prior notice of the areas you will cover. The only exception might be if you are (probably unfairly) refused a short adjournment to discuss with him a new issue which has arisen during the hearing and (after very careful consideration) you feel sufficiently confident to raise the issue with him 'raw' in examination in chief.
25.40 See paras 25.22 - 25.26 for preparation for cross-examination. If your expert is a good and confident witness then he can (and therefore should) be left to deal with most inappropriate or misleading questions himself (for example, where the question proceeds on a false premise). You will have already probed with him foreseeable lines of cross-examination so it should only be the oddest of questions that takes him completely by surprise.
25.41 Where a HOPO persists with a question that the expert has explained is inappropriate, you may wish to intervene. He should not, for example, be pressed to reveal anonymous sources. While the Practice Directions require that an expert's report states the substance of his instructions, they also prohibit cross-examination as to an expert's instructions unless the Tribunal rules that there are reasonable grounds to consider that his account of his instructions is incomplete or inaccurate (para 10.12 and see further para 23.6).
25.42 The expert should not be expected to have as detailed a recollection of your client's facts as you. Intervene where the HOPO makes inaccurate references to the factual evidence, for example dates of detention or details of family members. You are also freer to check the HOPO's references against the documents, whereas the expert will be concentrating on composing his answer.
25.43 A HOPO has been known to object to an expert referring to the views of others in his field (for example, describing the consensus view on an issue) on the ground that the expert is giving hearsay evidence. There is of course no rule prohibiting hearsay evidence in any event but even in other jurisdictions, it is well established that an expert may refer to the learning of others in his field to support his opinion without infringing the hearsay rule. A HOPO has even been known to object that the expert is stating his opinion rather than giving factual evidence. The Practice Directions (para 10.9) of course require that 'where there is a range of opinion on the matters dealt with in the report', the expert should 'summarise the range of opinion, so far as reasonably practicable, and give reasons for the expert's own opinion'. The only circumstance in which the HOPO may have a valid objection is where your expert strays beyond his expertise. Remind your expert beforehand of the points discussed in chapter 22 concerning what is and what is not appropriate.
25.44 Once again, the ordinary rules apply: the most impressive course is often not to re-examine at all. Even if your expert has been damaged in cross-examination, it will seldom be sensible to try to repair the damage unless you know what answer you will get. If the expert's answers have appeared ambiguous, then depending how thoroughly you have worked through the issues in conference, you may be able to formulate questions in a way that allows the expert to clarify matters.
25.45 Where a judge has restricted your evidence in chief, re-examination may also enable you to offer your expert a better opportunity to impress the judge through oral evidence on questions which arise from the HOPO's cross-examination and to ensure that the critical issues are at the forefront of the judge's mind.