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What are the duties of an expert witness in the immigration tribunal?


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Expert reports are common in asylum and human rights cases. They usually address either the conditions in the applicant’s country of origin or their physical or mental health.

The duties of an expert witness giving evidence in court are well established. Specific guidance for experts providing reports for cases in the immigration tribunals can be found at paragraph 10 of the relevant practice directions. Experts, and those instructing them, should read this paragraph of the directions in full.

In short, an expert’s paramount duty is to the tribunal. They are there to assist the tribunal to reach a decision by providing an objective, unbiased opinion on matters within their expertise. They are not there to advocate for either the appellant or the Home Office. Expert evidence should be the independent product of the expert, uninfluenced by the pressures of litigation.

An expert should consider all material facts, including those which might contradict their opinion. They should make it clear when an issue falls outside of their area of expertise or where they cannot reach a definite opinion (e.g. due to insufficient information). Their report should contain all of the information listed in paragraph 10.9 (qualifications, background facts, summary of conclusions etc.) and the statement of truth mentioned in paragraph 10.11.

In HA (expert evidence, mental health) Sri Lanka [2022] UKUT 111 (IAC) the Upper Tribunal provides some further guidance on the use of expert reports. Although specific to mental health reports, much of the guidance applies to expert reports generally.

The difficulty with mental health cases

Mental health is not an exact science. It is often more straightforward for a clinician to reach a diagnosis about a physical illness than it is for a mental illness.

An expert psychiatrist or psychologist may be asked to make a diagnosis and comment on any deterioration in the person’s mental health if they were required to leave the UK (including assessing the risk of suicide). Different medical professionals, with the same qualifications and experience, may reach different conclusions on these questions as they involve an evaluative judgement.

As noted by the Upper Tribunal in the first two paragraphs of the HA headnote, this makes it all the more important that the expert provides an objective and unbiased opinion:

(1) Where an expert report concerns the mental health of an individual, the Tribunal will be particularly reliant upon the author fully complying with their obligations as an expert, as well as upon their adherence to the standards and principles of the expert’s professional regulator. When doctors are acting as witnesses in legal proceedings they should adhere to the relevant GMC Guidance.

(2) Although the duties of an expert giving evidence about an individual’s mental health will be the same as those of an expert giving evidence about any other matter, the former must at all times be aware of the particular position they hold, in giving evidence about a condition which cannot be seen by the naked eye, X-rayed, scanned or measured in a test tube; and which therefore relies particularly heavily on the individual clinician’s opinion.

The GMC (General Medical Council) guidance referred to states at paragraph 72:

You must be honest and trustworthy when giving evidence to courts or tribunals. You must make sure that any evidence you give or documents you write or sign are not false or misleading.

(a) you must take reasonable steps to check the information.

(b) you must not deliberately leave out relevant information.

This raises the question: what information is relevant?

What is “relevant information”?

An expert must include information about their own qualifications and experience, as well as information about the person who is the subject of the report and their findings in relation to that person. In HA the Upper Tribunal has confirmed that the duty to provide an objective and unbiased account applies when they are establishing their credentials as well as when they are providing an opinion on the case:

… if an expert chooses to go beyond the ‘bare’ recitation of their professional qualifications and experience, the expert assumes a duty to ensure that the additional proffered material represents an ‘even-handed’ or fair picture. [Paragraph 114]

One of the experts who gave evidence in the case had failed to mention “…the fact that he had been suspended from practice [by the GMC] for bringing the profession into dispute as a result of his plagiaristic activities”. The suspension was for a period of three months in 2008.

The expert (understandably) did not think this was directly relevant to a report about HA’s mental health in 2021. He accepted that “had his dishonesty arisen in a clinical context, or in giving an opinion in an expert report, then it would unquestionably have been misleading for him to omit it from any subsequent report”. A mistake that occurred in relation to an act of journalism was, he considered, different.

The tribunal disagreed, taking the view that the expert had:

… sought to enhance his professional reputation, in the eyes of the Tribunal, by referring… to media perceptions of his standing as a psychiatrist…

Notwithstanding the GMC decision, he was still using the public persona he had enjoyed in the early 2000s to burnish his professional profile as a psychiatrist. [Paragraphs 115 and 117]

The judges concluded that the expert had “failed to give an even-handed account of his history as a psychiatrist” and that his reports were “misleading” as they gave the impression that he had an “unblemished record”.

What happens when an expert fails to observe these duties?

An expert shouldn’t just pay lip service to their duties. They must comply in substance:

In all cases in which expert evidence is adduced, the Tribunal should be scrupulous in ensuring that the expert has not merely recited their obligations, at the beginning or end of their report, but has actually complied with them in substance. [Paragraph 6 of headnote; paragraph 162 of judgment]

If they don’t, the tribunal may refer them to their professional regulator (e.g. the GMC):

Where there has been significant non-compliance, the Tribunal should say so in terms, in its decision. Furthermore, those giving expert evidence should be aware that the Tribunal is likely to pursue the matter with the relevant regulatory body, in the absence of a satisfactory explanation for the failure.[Paragraph 6 of headnote; paragraph 162 of judgment]

There will also be consequences for the appellant. The law on admissibility of evidence does not apply in the tribunal, so it cannot exclude the report as inadmissible. However, the tribunal can give it less weight: 

The production by an expert witness of a misleading report is, plainly, a significant matter that the court or tribunal must take into account, in deciding the weight to place upon the report and any additional evidence given by the person concerned in the course of the proceedings. [Paragraph 119]

The tribunal is not required to accept expert evidence if it disagrees with it: see MS (Zimbabwe) v Secretary of State for the Home Department [2021] EWCA Civ 941 at [61]. The tribunal must reach its own conclusions. This is true even if the expert has complied with all of their duties. However, as highlighted in MS (Zimbabwe), the tribunal is:

… entitled, and obliged, to ask itself whether [the expert’s] conclusions were rational conclusions, and whether, and if so, to what extent, they were supported by the material cited in the Report. The more inscrutable an expert’s conclusion is, the less likely it is that a tribunal of fact will be obliged to accept it. [Paragraph 62]

There is little point in obtaining a report that the tribunal won’t accept, so it is important that those instructing experts ensure the guidance above is complied with.

The relevance of GP records

An expert must engage with all of the evidence, even evidence which may “detract from his or her opinion”. In the context of a medical report, this includes GP records. A GP may not have identified a mental health condition or may take a different view on its severity from the expert psychologist or psychiatrist instructed to prepare a report. They have, however, interacted with the person over a prolonged period of time. This makes their observations more reliable than the observations of an expert, who is likely to have met the person only once or twice.

The tribunal’s guidance on this issue is summarised at paragraphs 3 to 5 of the headnote (which mirror paragraphs 159 to 161 of the judgment):

(3) It is trite that a psychiatrist possesses expertise that a general practitioner may not have. A psychiatrist may well be in a position to diagnose a variety of mental illnesses, including PTSD, following face-to-face consultation with the individual concerned. In the case of human rights and protection appeals, however, it would be naive to discount the possibility that an individual facing removal from the United Kingdom might wish to fabricate or exaggerate symptoms of mental illness, in order to defeat the respondent’s attempts at removal. A meeting between a psychiatrist, who is to be an expert witness, and the individual who is appealing an adverse decision of the respondent in the immigration field will necessarily be directly concerned with the individual’s attempt to remain in the United Kingdom on human rights grounds.

(4) Notwithstanding their limitations, the GP records concerning the individual detail a specific record of presentation and may paint a broader picture of his or her mental health than is available to the expert psychiatrist, particularly where the individual and the GP (and any associated health care professionals) have interacted over a significant period of time, during some of which the individual may not have perceived themselves as being at risk of removal.

(5) Accordingly, as a general matter, GP records are likely to be regarded by the Tribunal as directly relevant to the assessment of the individual’s mental health and should be engaged with by the expert in their report. Where the expert’s opinion differs from (or might appear, to a layperson, to differ from) the GP records, the expert will be expected to say so in the report, as part of their obligations as an expert witness. The Tribunal is unlikely to be satisfied by a report which merely attempts to brush aside the GP records.

This does not mean that an expert cannot disagree with the conclusions of a GP. But if they do disagree, they must draw attention to the contradictory information and explain why they disagree with it.

When to lodge an expert report

Expert reports should be lodged well in advance of the hearing. In HA the Home Office instructed an expert as well. This is unusual (as is the instruction of a QC in an Upper Tribunal case).

The tribunal notes that in future “greater use may be made of joint expert reports”, perhaps referring to Home Office plans to establish a “panel of pre-approved experts” (see the New Plan for Immigration policy statement). For the time being, the following guidance is provided in the headnote:

(7) Leaving aside the possibility of the parties jointly instructing an expert witness, the filing of an expert report by the appellant in good time before a hearing means that the Secretary of State will be expected to decide, in each case, whether the contents of the report are agreed. This will require the respondent to examine the report in detail, making any investigation that she may think necessary concerning the author of the report, such as by interrogating the GMC’s website for matters pertaining to registration.

The tribunal does not provide any guidance on what “in good time” means. In practice, the MyHMCTS appeal process is likely to avoid the problem of reports being sent at the last minute. Appellants are now required to lodge all evidence early in the process, together with an Appeal Skeleton Argument. The Home Office then responds to this, providing an opportunity for expert evidence to be considered well in advance of the hearing.

How to ensure that experts comply

What can an immigration practitioner do to reduce the chances of an expert report being given little weight by the tribunal? The tribunal in HA has highlighted a lot of problems, but not provided many solutions.

I have attempted to provide some guidance. It is by no means comprehensive or foolproof.

  • Before instructing an expert, search for their name online. A general Google search can be useful. A search of the tribunal determinations database or BAILII may unearth past cases in which the expert has given evidence (and any judicial praise or criticism). Following HA, a search of the GMC website would also be worthwhile.
  • Provide a detailed letter of instruction asking open questions. For example: “Please comment on whether, in your view, there is a risk of suicide if the appellant is required to leave the UK. If there is such a risk, please comment on the severity of the risk”. Try not to suggest within the question what you would like the answers to be. For example, don’t ask: “Please comment on whether there is a high risk of suicide if the appellant is forced to leave the UK against his will”.   
  • Draw the expert’s attention to their duties. Don’t assume they will already be familiar with the practice direction or GMC guidance mentioned above.
  • Provide all relevant information and documents including GP records, immigration history, representations submitted with the application, refusal letters, and any previous tribunal determinations.
  • Draw inaccuracies to the expert’s attention. The expert should not reach a clinical opinion based on what the appellant has said, irrespective of whether that is objectively true (see paragraph 122 of HA). The tribunal will be critical of a lack of attention to detail.
  • Ask the expert to consider whether the appellant could be fabricating or exaggerating the symptoms of mental illness. If they take the view that this is unlikely, ensure they explain why in their report.
  • Ask for clarification where you feel the expert hasn’t fully explained their reasoning. An expert needs to show their workings. If, after reading the report, you’re unsure what the justification for a particular opinion is, then chances are the tribunal will face the same problem. The evidence which supports an assertion needs to be clear on the face of the report.
  • Encourage neutral language. The tribunal is likely to call into question the independence of an expert who refers to “our case” (see paragraph 148 of HA). Similarly, references to “us” and “we” should be avoided. The expert should not give the impression they are on the appellant’s side. They should be independent.
  • Ensure that it is clear who the author of the report is. This should be an individual, not a firm or group of people.
  • Use paragraphs 10.9 to 10.11 of the practice direction mentioned above as a checklist. Go through the report to ensure it contains all of the information and statements required.

It is a difficult balance. Drawing an expert’s attention to matters which might lead them to a conclusion which is less advantageous for your client may seem counterintuitive. You may feel it goes against your duty to act in your client’s best interests. But, in the long run, it is in your client’s best interests to receive a balanced, objective and unbiased expert report that the tribunal can rely on. It is not in your client’s interests to spend time and money obtaining a report that the tribunal can simply disregard.

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Iain Halliday

Iain Halliday is an Advocate (the Scottish equivalent of a Barrister) at Themis Advocates. He specialises in public law, including immigration and asylum, retained EU law, human rights, and judicial review.