GUIDES
CPR Part 35 governs expert evidence in civil proceedings in England and Wales. It requires independent assistance to the court, permission to rely on expert evidence and a report that explains the evidence, instructions, reasoning and limits of the opinion.
Author: Nellie Supports Ltd
Publication Date: 15/05/2026
Masterman-Lister v Brutton & Co [2002] EWCA Civ 1889.
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CPR Part 35 governs expert evidence in civil proceedings in England and Wales. It requires independent assistance to the court, permission to rely on expert evidence and a report that explains the evidence, instructions, reasoning and limits of the opinion. This guide covers the relevant evidence, support, process and limits in England and Wales.
CPR Part 35 governs expert evidence in civil proceedings in England and Wales. It requires independent assistance to the court, permission to rely on expert evidence and a report that explains the evidence, instructions, reasoning and limits of the opinion. Capacity evidence can concern different decisions and tests. Court of Protection and family proceedings have their own rules; do not assume Part 35 automatically applies to every capacity assessment.
Review the decision and relevant time the report was instructed to address. Check the applicable legal test, sources, support and reasoning. A critical review of a will, gift, residence or financial opinion does not automatically ask whether the person can conduct proceedings; litigation capacity is a separate question where it arises.
Start by presuming capacity and taking all practicable steps to support the person. An unwise decision does not by itself establish incapacity. For this decision at this time, assess whether the person can understand and retain the relevant information, use or weigh it and communicate a decision by any means. If an ability is absent, explain whether an impairment of, or disturbance in the functioning of, the mind or brain causes that inability. Short retention is enough if it enables the decision.
Identify the information relevant to the decision actually assessed. For litigation, consider the properly framed proceedings as a whole with available legal advice and support; for other decisions, use their own material options and consequences. Check whether the report applies the correct test rather than importing a generic checklist.
The assessment is stronger when the evidence is organised before the conclusion is reached. Useful evidence may include the letter of instruction, pleadings or application documents, solicitor attendance notes, expert evidence, court orders, witness statements and records of the person’s instructions. Where records are missing, contradictory or out of date, the report should say so rather than overstate the certainty of the opinion.
The person should be given a meaningful opportunity to make the decision. This may involve simple language, written summaries, visual aids, additional time, breaks, support with hearing or sight, an interpreter, a familiar setting or a carefully timed appointment. The report should explain what support was tried and whether it helped.
Check whether the report explains the person’s own reasoning and each relevant ability, rather than only their ability to repeat information. For an MCA opinion, any inability must be causally linked to an impairment or disturbance. Disagreeing with the decision or the expert’s conclusion is not itself an evidential flaw.
Distinguish a problem in the legal test or evidence from risk, disagreement or vulnerability alone. Consider whether another report concerns the same decision, time and support before treating the conclusions as contradictory. Seek legal advice on the materiality of the concern and any further expert evidence.
A strong report should include the instruction, the specific decision, the legal framework, the relevant information, evidence reviewed, practicable steps, direct assessment findings, functional analysis, causation and a clear conclusion. It should also explain any limitations, such as missing evidence, refusal to engage, fluctuating presentation or the need for further legal advice.
A critical review should identify a material issue and explain how it affects the opinion. Clarification may resolve a gap; changed circumstances or a substantive methodological problem may require further assessment. The court evaluates expert evidence and decides the legal issues.
No. A diagnosis does not establish lack of capacity. For a decision under the Mental Capacity Act, consider the relevant information and practicable support, then assess understanding, retention, use or weighing and communication by any means. Any inability must be caused by an impairment of, or disturbance in the functioning of, the mind or brain. Will-making has its own legal test.
The letter of instruction, the pleadings identifying why capacity is in issue, the medical and care records, and any earlier capacity assessments. Under Part 35 the report must state the substance of all material instructions, so instructions should be written on the assumption that the court will read them.
Part 35 compliance matters most where capacity is contested between the parties, where a settlement involving a protected party requires court approval, or where an existing report's independence or reasoning is under attack and replacement evidence will need the court's permission. Can someone have capacity for one decision but not another? Yes. Capacity is decision-specific and time-specific. The assessment must identify each decision and relevant time rather than give a general label.
The related guides below provide further explanation of the decisions, evidence and legal processes discussed here.
Check the permission order and Practice Direction 35 before instruction. Keep the questions within the expert’s competence and agree the records, costs, timetable and arrangements for properly permitted clarification.
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