Who is a medical expert? How do we know that such experts are impartial?

In a recent High Court decision ^a concerning a challenge to detention under immigration powers, the judge declined to admit two reports by a general practitioner (GP) as expert evidence. The judge considered that because the doctor was not a consultant psychiatrist, he did not ‘have the specialist knowledge or experience to be able to provide expert evidence’ in this case. In addition, the judge noted that the Home Office (the opposing party in the case) argued that since the doctor worked for a charity opposed to immigration detention, he may have been ‘not sufficiently impartial’. The judge stated that they did not doubt the doctor's professional independence, but nonetheless appeared to give some credence to the Home Office's argument by stating that if expert evidence were required later, ‘it might be desirable to appoint someone who is not working in a non-governmental organisation (NGO) which might conceivably be seen as pro-detainee’.

The case in question concerned an immigration detainee who had been diagnosed with paranoid schizophrenia with psychotic features and antisocial personality disorder. Bail had been granted, but there were difficulties in arranging a bail address and an appropriate level of care if he was in the community. This had led to many weeks of delay in his release.

The opinion requested was in relation to specific clinical issues such as the Claimant's mental health diagnoses, his fitness to be detained, and whether detention was likely to have caused or be causing worsening in the Claimant's mental health. However, the key questions raised in the judgement (which potentially have wider implications) are whether the ‘expert’ had sufficient expertise to answer the specific questions raised, and whether working for an NGO could mean that the evidence given was biased or would be perceived as biased.

Can a GP have sufficient expertise to give an opinion in the context of post-traumatic stress disorder and specifically on the impact of detention?

The overwhelming majority of patients across the range of psychological and psychiatric disorders, from mild anxiety and stress to psychotic conditions, are managed in the community. GPs therefore have a wide experience of assessment and continuing care for this population. The GP will regularly review which among their patients with significant mental health problems are managing sufficiently and who need additional care and support from secondary mental health care services.

The fact that the GP in this case worked for a charity working to provide immigration detainees with an independent medical opinion about their health (while also campaigning against such detention) meant that he had visited numerous patients detained under immigration powers and assessed first-hand the impact of the conditions of detention upon them. This formed the basis of the additional experience he required to be able to give an expert opinion in this particular case.

The potential for detention to harm mental health is a recognised issue and is neither rare nor an unexpected outcome. There is a wealth of clinical research to this effect from many independent sources. As well as a systematic review in a peer-reviewed journal, which one of us co-authored,1 this includes the views of government-appointed experts such as Stephen Shaw, who reviewed the impact of immigration detention in 2015–20162 and 2017–2018,3–4

Immigration detention is administrative, and detainees may be released if their health is being seriously harmed. It is a premise of the Detention Rule 35/Adults at Risk framework that GPs are qualified to assess the impact of immigration detention, and they can issue ‘Rule 35 reports’ – the primary mechanism of providing safeguards for those whose health (in the majority of cases, the detainee's mental health) may be harmed by ongoing immigration detention.

That doctors need not be psychiatrists to give an opinion on a patient with a psychiatric condition is recognised by the Home Office, in their Asylum Policy Instruction (API) on Medical Evidence, which states that ‘Medical evidence should not be given little weight, including in relation to mental health conditions, because of the type of clinician preparing it where they have experience in that field and are regulated professionals’.5

In keeping with this, the General Medical Council (GMC) guidance on providing expert witness reports6 states at paragraph 12.7 that doctors should only give opinions ‘on matters within your professional competence or where you have the relevant knowledge’. Where a matter falls outside this, they should explain and decline to answer or comment. It is knowledge of the relevant standards and nature of the clinical practice in question, and experience in the care of patients with particular needs that is relevant (paragraph 18 of the GMC guidance), rather than a specific qualification or specialism.

There is a key judgement on this point in the Supreme Court: Kennedy v Cordia Services LLP [2016] UKSC 6 (Kennedy), in which Lord Reed and Lord Hodge identified that in considering the admissibility of expert evidence, an important consideration is ‘whether the witness has the necessary knowledge and experience…by dint of training and practice’. Their opinion was that it is possible to ‘acquire expert knowledge in a particular sphere through repeated contact with it in the course of one’s work, notwithstanding that the expertise is derived from experience and not formal training’.

More generally, there is no legal or medical requirement for a doctor to be a consultant psychiatrist or, for example, to hold section 12 approval under the Mental Health Act in order to give an opinion on a psychiatric patient's mental health. There is therefore no reason why a GP who can demonstrate from their curriculum vitae that they have acquired the relevant knowledge and clinical experience to give such an opinion should not do so.

Can a doctor working for a charity opposed to immigration detention be independent, objective, and impartial in their assessment of whether or not a detained person's mental health has been, or is likely to be, harmed by detention?

The court rules on expert evidence ^b make clear that all medical experts – regardless of which ‘side’ has instructed them, who employs them or who has provided them with training ^c – owe an overriding duty to the court, and a duty of independence, objectivity and impartiality. The court rules require the expert to confirm in the body of their report that they understand these duties and have complied with them.

The court rules also require the expert to sign a ‘Statement of Truth’ confirming that they have made clear within the report which facts and matters are within their own knowledge and which are not, and to confirm the truth of those within their knowledge. It also requires the expert to confirm the truth and completeness of the professional opinions expressed in the report.

In the immigration context, joint instruction of medical experts – an obvious means of dealing with concern about ‘bias’ in medical evidence – is very rare because the Home Office hardly ever either suggests instructing experts jointly or commissions its own expert medical evidence.

To assert that an expert has not, or might not, have complied with these duties, and that their opinion can therefore be set aside, constitutes an allegation that their Statement of Truth is untrue. If such an allegation were substantiated, it could amount to contempt of court, as the Statement of Truth itself acknowledges.

It is also important to note that the ethical principles underlying these rules reflect doctors’ training, the GMC guidance for expert witness reports, and the Home Office's own API on medical evidence in asylum claims.

At paragraph 12.8, the GMC guidance states that ‘you must not allow any personal or professional relationship with, or personal views that you might have about, individuals or organisations, to affect the objectivity or independence of any statement or evidence that you provide’. Paragraph 22 reiterates that ‘you have a duty to the Court which requires you to act independently and to be objective and impartial, overriding any obligation you may have to the person instructing you or paying you to provide an expert opinion.’

The Home Office guidance on medical evidence in asylum claims7 incorporates reference to the Istanbul Protocol ^d (the United Nations Manual on the effective investigation and documentation of torture and other cruel, inhuman or degrading treatment or punishment), as a guide for training doctors and producing expert medicolegal reports for these patients: ‘Medical evidence compiled in accordance with recognised standards and a framework, for example the Istanbul Protocol…such reports are objective and unbiased [our emboldening]’. The Istanbul Protocol requires the clinician to assess each clinical finding for its level of consistency with the person's attribution, and then also to give an opinion on the overall consistency of all the findings. The rigour of that process is itself a strong protection against bias.

Doctors are trained to form an independent opinion and not to believe everything their patients tell them. While medical training begins with Osler's mantra ‘listen to the patient, they will give you the diagnosis’,8 this does not mean wholesale acceptance of the patient's word. Instead, the key is active listening and then assessing what the patient says together with observations of how they speak, their body language, their responses to clinical questions, examination findings, and the doctor's own knowledge and experience. The good doctor does not believe what the patient tells them about how much they drink, smoke, or exercise, and views their protestations about crippling back pain alongside the machine oil stains on their cuticles and the calluses on their palm.

Trust in experts is currently under threat in many spheres.9 If a doubt is raised about an expert's opinion, there should indeed be a process to alleviate – or vindicate – that concern, but existing guidance both as to specialist knowledge and as to independence is already clearly set out for both expert witness and the judge to follow. There are, therefore, clear and wide-ranging potential dangers of misinterpreting and misapplying in future cases the High Court decision we have discussed.