GUIDES
A solicitor instructing a capacity expert should identify the proceedings, the precise question and relevant date, the applicable test, the records and the court’s directions. CPR Part 35 and Practice Direction 35 govern expert evidence in civil proceedings; other courts have their own rules.
Author: Nellie Supports Ltd
Publication Date: 15/05/2026
Masterman-Lister v Brutton & Co [2002] EWCA Civ 1889.
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A solicitor instructing a capacity expert should identify the proceedings, the precise question and relevant date, the applicable test, the records and the court’s directions. CPR Part 35 and Practice Direction 35 govern expert evidence in civil proceedings; other courts have their own rules. This guide covers the relevant evidence, support, process and limits in England and Wales.
A solicitor instructing a capacity expert should identify the proceedings, the precise question and relevant date, the applicable test, the records and the court’s directions. CPR Part 35 and Practice Direction 35 govern expert evidence in civil proceedings; other courts have their own rules.
CPR Part 35 restricts expert evidence to what is reasonably required to resolve the proceedings and requires the court’s permission to rely on it. An expert assists the court within their expertise, independently of the party paying. Practice Direction 35 supplies additional report requirements.
A clear letter of instruction identifies the specific decision in question, the proceedings, the issues the expert must address and the documents provided. Because capacity is decision-specific under the Mental Capacity Act 2005, an instruction that asks whether a person has capacity in general terms invites a report that answers the wrong question. Name the decision, the relevant timeframe and any known impairment or diagnosis, and enclose the records that bear on them.
The expert’s overriding duty is to the court. Instructions and payment must not require a preferred conclusion. Ask the expert to disclose relevant connections, distinguish facts and opinion, address contrary material and explain limits or matters outside their expertise.
Alongside the requirements of CPR Part 35 and Practice Direction 35, a capacity opinion should identify the question and time, correct test, evidence, relevant information, support, findings and reasoning. For an MCA question, explain the functional abilities before the causal link to impairment. A will requires the testamentary test instead. Include the required declarations and statement of truth.
Agree a delivery date based on access, the records, support needs and work required. A Part 35 report has no universal seven-to-fourteen-day production period. Flag court deadlines early and agree the response if evidence is delayed.
CPR 35.6 ordinarily permits proportionate written clarification questions once, within 28 days of service, unless the court permits or the other party agrees otherwise. The rule concerns questions to another party’s expert or a single joint expert. Other supplementary work and discussions follow the applicable rules and directions; agree availability and fees at instruction.
Material weaknesses can include an unclear question, the wrong test, inadequate support, unsupported findings or a conclusion that does not follow from the evidence. Clarify the significance of the gap and address it within the applicable procedure.
The court may direct a single joint expert under CPR 35.7. Agree or obtain directions on the expert, questions and instructions, and follow the rules on sharing instructions and communications. Joint instruction does not reduce the expert’s duty of independence to the court.
A clear instruction and a reasoned, independent opinion help the court evaluate capacity evidence. Confirm the applicable test, directions, permission, report requirements and follow-up rather than treating compliance as a guarantee of acceptance.
No. Part 35 governs expert evidence in civil proceedings. Private or administrative assessments do not automatically require that format, and Court of Protection and family proceedings have their own rules. Confirm the intended use and applicable procedure.
The letter of instruction, the pleadings identifying why capacity is in issue, the medical and care records and any earlier assessments. Under Part 35 the report must state the substance of all material instructions, so instructions should be written on the assumption the court will read them.
There is no fixed production period: agree a realistic date based on the work and court timetable. Confirm availability and charges for properly permitted questions, supplementary reports, expert discussions or attendance rather than assuming these are included.
The related guides below provide further explanation of the decisions, evidence and legal processes discussed here.
Use a clear letter of instruction and an indexed set of relevant papers. Confirm the applicable rules, court permission, report requirements, agreed delivery date and any further fees for questions, meetings or attendance.
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