Psychological evidence in medical negligence claims: choosing the right expert

Psychological evidence can be important in medical negligence claims involving psychological injury, cognitive impairment, treatment needs, rehabilitation, capacity or loss of earnings. Its value, however, depends on whether the person providing the opinion has the qualifications and specialist expertise required to address the issues in dispute.

The expert’s professional title is only the starting point. Medical negligence solicitors should examine the proposed expert’s regulatory status, current practice, assessment methods and experience of the particular condition before an instruction is confirmed.

Understanding professional titles

The general titles ‘psychologist’ and ‘psychotherapist’ are not protected by law. Certain practitioner psychologist titles, including ‘clinical psychologist’ and ‘counselling psychologist’, may be used only by professionals registered with the Health and Care Professions Council. Solicitors should therefore verify a proposed expert’s registration, qualifications and relevant experience rather than relying on their title alone.

Registration is important, but it does not establish competence to address every psychological question. A registered psychologist may have extensive therapeutic experience, but limited experience of formal assessment, psychometric testing, or the particular presentation involved in the claim. Similarly, an experienced psychotherapist may not be qualified to undertake diagnostic assessment, evaluate capacity or express an independent opinion on legal causation.

The relevant question is whether the proposed expert is competent to answer each question in the letter of instruction.

The requirements of CPR part 35

Under CPR 35.3, an expert’s overriding duty is to help the court on matters within their expertise. That duty overrides any obligation to the party instructing them. CPR 35.4 also requires a party seeking permission for expert evidence to identify the relevant field and the issues that the evidence will address.

Practice Direction 35 requires expert evidence to be independent and objective. Experts must consider material that may undermine their conclusions and state when a question falls outside their expertise, or when the available evidence does not support a definite opinion. They must not assume the role of an advocate.

These obligations require more than competence as a treating practitioner. An expert must be able to evaluate competing evidence, explain their reasoning and distinguish between matters that fall within their expertise and factual disputes reserved for the court.

This is particularly important where a report is expected to address diagnosis, causation, prognosis, treatment and capacity. Experience in one area should not be assumed to establish expertise in all of them.

Checking the proposed expert’s credentials

A proposed expert’s CV should be reviewed critically. It should identify the expert’s qualifications, regulatory status, current practice, specialist interests and experience of the condition or presentation in issue.

Where psychometric or other formal testing is proposed, solicitors should establish whether the expert is trained and competent to administer and interpret the relevant tool. A test result is not self-explanatory. Its reliability may depend on whether the test was suitable for the claimant, administered correctly and interpreted in the context of the claimant’s clinical history, background and communication needs.

Additional care is required when considering a psychotherapist. As ‘psychotherapist’ is not a title protected by the Health and Care Professions Council, solicitors should establish the individual’s training, accreditation, professional membership and current scope of practice.

Accreditation or registration provides useful assurance, but it does not replace case-specific scrutiny. The solicitor must match the practitioner’s actual competence to the questions requiring expert evidence.

Lessons from recent cases

There is limited reported medical negligence case law addressing the competence of psychologists or psychotherapists as experts. Recent family cases nevertheless provide useful warnings about professional status, expert selection and the limits of expertise.

The procedural framework in family proceedings differs from CPR part 35. These cases are not direct medical negligence authorities and should not be treated as such. Their broader lessons are, however, relevant to solicitors instructing psychological experts.

In Re C (‘Parental Alienation’; Instruction of Expert) [2023], the court considered a challenge involving an expert who described herself as a psychologist but was not registered with the Health and Care Professions Council or chartered by the British Psychological Society. The appeal was dismissed, but the President of the Family Division emphasised the need for rigour when identifying and approving psychologists as experts.

The case does not establish that an unregistered psychologist can never give expert evidence. Its practical significance is that the generic title ‘psychologist’ does not establish regulatory status or competence. Following the decision, guidance for psychologists acting in family proceedings was updated to reinforce the scrutiny of regulation, qualifications and access to psychological tests.

In H (Children: Expertise of Witness) [2026], the Court of Appeal considered an appeal concerning a jointly instructed psychologist. When accepting the instruction, the expert had disclosed that a regulatory tribunal hearing was pending, but the disclosure was not brought to the attention of the parents or the court. The underlying complaint concerned allegations that the expert had undertaken clinical psychological assessment and psychometric testing without being registered or qualified to do so.

The appeal was dismissed. The court did not conclude that the original orders were undermined by the expert’s involvement. The judgment should not therefore be presented as establishing that regulatory status alone determines whether psychological evidence is admissible or reliable.

The case does, however, emphasise the importance of transparency. Material information disclosed by a proposed expert must be considered carefully and communicated where relevant. Solicitors should also examine the substance of the proposed assessment, including the methods and tests to be used, rather than relying on the label attached to it.

In Liverpool City Council v Ms A and others [2025], the parties agreed that a clinical psychologist’s report was fundamentally flawed, and a replacement expert was required. The expert had failed to approach the assessment on the basis of factual findings already made by the court.

The decision illustrates the importance of a precise letter of instruction. Experts should be told which facts are agreed, disputed or assumed. They must not take over the court’s role by revisiting findings or resolving factual disputes outside the proper scope of their evidence.

Treating psychotherapists and independent experts

A treating psychotherapist may hold important factual evidence about a claimant’s reported symptoms, presentation, treatment and progress. That does not automatically qualify the practitioner to provide independent opinion evidence on diagnosis, causation, prognosis or capacity.

The distinction between factual and expert evidence should be maintained. A treating psychotherapist can explain what was reported, observed and recorded during therapy. However, treatment may proceed on the basis of the client’s account without testing that account against medical records, witness evidence or alternative explanations.

An independent expert must take a different approach. The expert should review the evidence as a whole, consider competing explanations, and provide an objective opinion. Where a treating practitioner is proposed as an expert, solicitors should also consider whether the existing therapeutic relationship could affect, or appear to affect, their independence.

Practical points for medical negligence solicitors

Before instructing a psychologist or psychotherapist, solicitors should:

• verify their qualifications, regulatory status, accreditation and current area of practice;
• confirm that their expertise matches each issue in the letter of instruction;
• establish their competence to administer and interpret any proposed tests;
• distinguish treating evidence from independent expert opinion;
• identify clearly which facts are agreed, disputed or assumed; and
• check for relevant regulatory restrictions or previous judicial criticism.

The completed report should then be reviewed for unsupported conclusions, advocacy, failure to address contrary evidence and opinions extending beyond the expert’s competence.

Conclusion

Psychological evidence can make a significant contribution to a medical negligence claim, but only where the right professional is asked the right questions.

The titles ‘psychologist’ and ‘psychotherapist’ do not, without more, establish regulated status or medico-legal expertise. Equally, registration or accreditation does not demonstrate competence across every psychological issue.

Medical negligence solicitors should look beyond titles and examine the proposed expert’s qualifications, current practice, methodology and experience of the issues in dispute. Careful selection at the outset reduces the risk of unreliable evidence, unnecessary costs and the need to obtain a replacement report later in the proceedings.