PastPaperHero | Evidence and disclosure

Learning Outcomes

This article explains the rules and procedures governing expert evidence in civil litigation under CPR Part 35, including:

when opinion evidence from an expert is admissible, how it differs from lay evidence, and when the court will regard it as reasonably required;
the expert’s overriding duty to the court, independence, and the professional and ethical limits on solicitor and client influence;
the court’s case management powers to control expert evidence, such as restricting issues, limiting the number of experts, and preferring single joint experts where proportionate;
the requirements and practice for seeking permission to rely on expert evidence, with emphasis on the information, timing, and costs estimates needed for a compliant application;
practical rules for instructing experts, including the status and potential disclosure of instructions and the selection, role, and operation of single joint experts;
mandatory content and format of expert reports under CPR 35.10 and PD 35, and the consequences of non-compliance;
the conduct and purpose of experts’ discussions, joint statements, and written questions, and how these narrow issues for trial;
the principles governing service, use, and replacement of expert reports, the effect of late or defective disclosure, and how these matters are likely to be tested in the SQE1 FLK1 exam.

SQE1 Syllabus

For SQE1, you are required to identify and apply the core legal principles and rules regarding expert evidence in civil cases, with a focus on the following syllabus points:

The admissibility of expert as distinct from lay opinion evidence (Civil Evidence Act 1972, s.3).
The overriding duty of experts to the court (CPR 35.3); impartiality and objectivity requirements.
The court’s active case management—restricting or permitting expert evidence, limiting oral evidence, and ordering joint experts (CPR 35.1, 35.4, Practice Direction 35).
Procedures for seeking permission to rely on expert evidence, including the content and timing of applications, required supporting information, and the making or service of application notices and evidence (CPR 35.4, Part 23).
The requirements and process for instructing experts, including the rules regarding the privilege and potential disclosure of instructions (CPR 35.10(4), PD 35.5).
The designation and procedural handling of Single Joint Experts (CPR 35.7), and distinctions between SJEs, agreed experts, and opposing party experts.
Detailed requirements for the content and form of expert reports (CPR 35.10, PD 35 para 3); statement of truth, duty statement, disclosure of assumptions, factual bases, range of opinion, and literature relied on.
The meeting of experts to discuss issues, the drafting of joint statements, and the principle of “without prejudice” discussions to narrow issues (CPR 35.12, PD 35 para 9.7).
The right to put written questions to experts within 28 days of report service, and the status of the answers (CPR 35.6).
The consequences of failing to serve or disclose an expert's report, including the circumstances for late service, relief applications, and the rights of other parties to rely on a disclosed expert report (CPR 35.11, 35.13).
Ethical and professional conduct issues, including improper influence, contingency arrangements, and appropriate handling of payments to experts.

Test Your Knowledge

Attempt these questions before reading this article. If you find some difficult or cannot remember the answers, remember to look more closely at that area during your revision.

To whom does an expert witness owe their primary duty?
1. The instructing party
2. The court
3. The client
4. Both parties jointly
Can a party rely on expert evidence without the court's permission?
1. Yes, if the expert is instructed jointly.
2. Yes, if the report is agreed by all parties.
3. No, court permission is always required under CPR 35.4.
4. Yes, in fast-track claims only.
What is the main purpose of discussions between experts under CPR 35.12?
1. To decide which expert's opinion is correct.
2. To negotiate a settlement between the parties.
3. To identify and narrow the issues on which they agree and disagree.
4. To prepare cross-examination questions for the trial.

Introduction

Expert evidence is central to civil litigation where the court requires technical or scientific knowledge beyond the experience of a lay judge. In this context, the procedural and substantive rules aim to ensure that expert input aids the court fairly and efficiently, maintaining proportionality in costs and time. The Civil Procedure Rules (CPR) Part 35, the Civil Evidence Acts, and Practice Direction 35 regulate the admissibility, form, and management of expert evidence, preserving the integrity and objectivity of expert input while aligning its use with the court's overarching case management objectives.

Key Term: expert witness
An individual instructed to provide or prepare expert evidence for court proceedings based on specific knowledge, skill, or experience in a particular field.

Expert opinion is admissible if the expert is suitably qualified and the opinion is on a relevant issue within their knowledge (Civil Evidence Act 1972, s.3). The court will only permit expert evidence where it is reasonably necessary for resolving matters in dispute (CPR 35.1). Ordinarily, permission is sought during the directions stage, but may be addressed by specific application as proceedings develop. The form of the expert input, whether written or oral, and the appointment of single joint experts, are managed with the overriding objective in mind: to deal with cases justly and at a proportionate cost.

The Expert's Duty

The rules require objectivity and independence. CPR 35.3 states that an expert’s duty is to assist the court—a duty that overrides any obligations to instructing parties, regardless of payment or contractual relationship.

Key Term: overriding duty
An expert’s primary obligation under CPR 35.3, to assist the court impartially on matters within their knowledge, which takes precedence over any instructions or interests of the instructing party.

This duty applies to every aspect of expert involvement in litigation. Experts must ensure:

Objectivity: Independence from the instructing party’s objectives is strictly required. An expert must not take on the role of advocate and must approach their assessment and reporting with a balanced and impartial mindset.
Scope of Opinion: Experts must confine themselves to matters within their competence. Where a question falls beyond their knowledge or the data is lacking, the expert should state the limitations, uncertainties, and any necessary qualifications to their opinion.
Transparency: Reports must disclose the substance of all material instructions and assumptions and distinguish between facts within the expert’s own knowledge and those sourced elsewhere.
Full and Reasoned Opinions: If reasonable views within the discipline differ, the expert must summarise the range of opinion, provide reasons for their own, and clarify why other opinions were discounted.
Updating Duties: Should the expert’s view change in light of new evidence—especially after meeting with opposing experts or reviewing further material—they must notify all parties and explain the reasons for the change within any joint statement or supplemental report.
Comprehensive Disclosure: Experts are duty-bound to disclose all material facts, including those adverse to the instructing party, and to reference all literature/research relied on.
Fee Arrangements: They must avoid all arrangements that tie payment to the outcome or substance of the opinion provided, in order to safeguard independence.
Procedural Compliance: They must be familiar with and comply with CPR Part 35, PD 35, the Guidance for the Instruction of Experts in Civil Claims, and relevant judicial guidance.

Although the expert’s main duty is owed to the court, they remain contractually obliged to the person instructing them to exercise reasonable care and skill (see Supply of Goods and Services Act 1982, s.13). Failure to perform these duties may result in the court placing little or no weight on their evidence, the report being excluded, and, in serious cases, professional or costs sanctions.

It is also a core element of professional and ethical conduct that solicitors must not seek to influence the substance of an expert's opinion or otherwise compromise their impartiality, in accordance with SRA rules and guidance.

Court's Power to Restrict Expert Evidence

The management powers of the court over expert evidence are fundamental to the current litigation system. CPR 35.1–35.4 provides that the court will only permit expert evidence where it is reasonably required to resolve disputed issues, having regard to proportionality, cost, and efficiency.

The court may grant, withhold, or limit permission to adduce expert evidence. Control measures include:

Refusing expert evidence entirely, if the issue can be determined by the judge unaided or if the evidence would not materially assist.
Limiting each party to one expert for each field or issue, or limiting the number of issues on which expert evidence can be given, in order to curtail duplication and excessive cost.
Directing that evidence on an issue be given by a single joint expert.
Refusing permission for oral expert evidence (common in fast-track claims, where written reports usually suffice).
Specifying the field of knowledge, the identity of the expert (where possible), and the precise issues the expert should address.

Case management directions may also include timetables for exchange of expert reports, dates for meetings between experts, and deadlines for serving questions on expert reports.

In multi-track disputes involving technical complexity or high value, the court often permits each party to instruct their own expert in distinct disciplines. However, it will scrutinise requests to ensure necessity, proportionality, and relevance.

When assessing the need for expert evidence, the court considers:

Complexity of the technical issues and whether they are within judicial knowledge.
Potential for experts to assist in resolving key disputes.
Costs relative to the value and importance of the claim.
Whether the issue genuinely requires knowledge or could be resolved on the documents.

Where possible, the court will restrict expert involvement to ensure both proportionality and fairness.

Applying for Permission

Applications for permission to rely on expert evidence must be supported by adequate information (CPR 35.4 and relevant practice directions). When seeking permission, a party must provide:

An estimate of costs for the proposed expert involvement.
A clear indication of the field or discipline in which evidence is required.
The specific issues upon which the expert is to report.
The name(s) of the proposed expert(s), where practicable.

Applications are commonly made in response to a directions questionnaire, during a case management conference, or (where necessary) by formal application notice under CPR Part 23. Supporting evidence, such as a witness statement or accompanying exhibits, should concisely explain why the evidence is reasonably required and include details of the expert's qualifications and experience where available. Service of application documents must comply with procedural rules, with notice typically served at least three clear days before any hearing, and supporting evidence and draft orders included.

The court will grant permission only to the extent that it considers expert evidence necessary. Permission may be granted for a named expert or for an expert in a specified discipline. Directions may also include deadlines for report exchange, questions to the expert, and meetings or joint statements.

If an application is made without notice (exceptional and usually reserved for urgent or confidential matters), the applicant must provide full justification and, once the order is granted, serve it together with supporting evidence and details of the right to set aside on the respondent.

Where parties agree on expert evidence (e.g., scope, identity, or instructions), the court can dispense with an oral hearing and make the order by consent to streamline proceedings.

Worked Example 1.1

In a claim for damages arising from allegedly defective building work, the Claimant wishes to rely on evidence from a structural engineer. What must the Claimant include in their application to the court for permission to use this expert evidence?

Answer:
The Claimant must identify the specialist field (structural engineering), the issues the expert will address (such as the causes of the defects and the required remedial work), the name and CV of the proposed expert (if known), and an estimate of their fees. Supporting evidence should explain why expert involvement is reasonably required.

Worked Example 1.2

A hotel group sues a software supplier over a flawed booking platform causing double bookings and data loss. The claim is high value, with technical questions of causation and loss. The claimant seeks permission for experts in IT systems (liability) and forensic accountancy (quantum). Will the court likely allow separate experts?

Answer:
Yes. The complexity and high value of the case, coupled with the distinct nature of liability (technical IT analysis) and quantum (forensic accountancy), means the court is likely to permit separate experts for each party in these disciplines. The court will control the scope of evidence, set directions for exchange, and may require experts in each field to confer later to narrow issues.

Instructing Experts

When instructing an expert, the solicitor should provide complete and balanced instructions, setting out the issues, assumptions, and background, and enclosing all relevant materials (including potentially adverse documentation). Practice Direction 35 encourages transparency and fairness.

Instructions to experts are not privileged as a matter of right. CPR 35.10(4) and PD 35 para 5 specify that the contents of instructions can be examined by the court if there are reasonable grounds to consider that the summary provided in the report is inaccurate or incomplete. The default rule, however, is that instructions are not disclosed unless the court orders, or unless the party who gave the instructions consents to disclosure.

Upon receipt of opposing experts’ reports, it is accepted practice to provide copies to your own expert for comment. Legal representatives must ensure that their conduct does not inappropriately influence the substance of the expert’s opinions, which would be unethical and potentially prejudicial to the integrity of the process.

Experts' fees must be calculated as reasonable fees and expenses for work performed. All contingency fees or success-based payments are prohibited. Solicitors must not enter arrangements that could compromise the expert’s independent role.

Single Joint Experts

Where appropriate, the court may direct that evidence about a particular issue be given by a single joint expert (SJE), jointly instructed by the relevant parties. This is particularly common in fast-track claims and lower-value disputes, where the cost and efficiency benefits are most significant.

Key Term: single joint expert
An expert instructed to prepare a report for the court on behalf of two or more parties to the proceedings, as directed by the court or agreed by the parties (CPR 35.7).

If parties are unable to agree on the selection of an SJE, the court may make the choice from lists provided, or specify an alternative method for selection. Instructions to an SJE should be drafted jointly; if agreement is not reached, each party may submit their own written instructions (shared with other instructing parties).

All communications by the SJE, including the final report, answers to questions, and other correspondence, must be provided to all parties at the same time. Initial costs are typically shared, but final liability for fees is determined after judgment, in accordance with the ultimate costs order.

In some claims, particularly under pre-action protocols, parties may rely on an “agreed expert” (not formally a joint expert), but both parties must still seek the court’s permission to call a further or different expert if needed.

The court considers various factors when deciding whether to appoint an SJE rather than allowing separate experts. These include the proportionality of costs (having regard to the value, importance, and complexity of the dispute), the likelihood of a range of opinion, whether instruction of an SJE will save time or cost, and whether the use of separate experts would be justified having regard to the facts of the case.

Worked Example 1.3

In a fast-track personal injury claim resulting from a road traffic accident, both parties need expert medical evidence on the prognosis for the Claimant’s whiplash injury. What is the court likely to direct regarding expert evidence?

Answer:
The court is likely to direct that a single joint medical expert be instructed by both parties to report on prognosis and the extent of injury. The geographical and financial context makes single instruction the most proportionate and efficient choice.

Worked Example 1.4

Two parties agree a need for valuation evidence on modest property damage but cannot agree on an expert. Each proposes two different surveyors. How might the court resolve this?

Answer:
Under CPR 35.7, the court may direct that evidence be given by a single joint expert and, since the parties cannot agree, may select one from a list provided or require a neutral method for selection. Cost efficiency and proportionality are central to this decision.

Revision Tip

Understand the factors the court considers when deciding whether to order a single joint expert (PD 35 para 7). These include proportionality with reference to the value and complexity of the issue, the likelihood of a range of expert opinions, and whether the issue is technical or likely to be resolved quickly and cost-effectively via joint instruction.

Content of Expert Reports

Strict compliance with CPR 35.10 and PD 35 para 3 is essential for the admissibility and weight of expert reports. Every report must meet rigorous standards to ensure reliability and transparency. Key elements include:

Addressed to the court, not to the instructing party, signifying the proper independence of the report.
Full name, address, and detailed qualifications of the expert, giving the court assurance as to the credibility of the knowledge.
Comprehensive list of all literature, materials, and data relied on, with clear references.
Unambiguous statement of the substance of all instructions—written or oral—making transparent the assumptions and context.
Clarity about which facts are within the expert’s knowledge and which are sourced from others, identifying sources where applicable.
Identification of who conducted any relevant examination, measurement, test, or experiment, stating their qualifications and whether carried out under the expert’s supervision.
Where the field is controversial, a summary of the range of opinion, with an explanation for the expert’s view over competing alternatives.
A clear and concise summary of the conclusions, highlighting the significant points in plain language for the benefit of the court.
Full disclosure of any limitations on the opinion, including lack of data, uncertainty, or any qualifications applied.
A statement confirming that the expert understands their duty to the court, has complied, and is familiar with Part 35, PD 35, and the Guidance for the Instruction of Experts in Civil Claims.
Verification by a statement of truth, in the form:
“I confirm that I have made clear which facts and matters referred to in this report are within my own knowledge and which are not. Those that are within my own knowledge I confirm to be true. The opinions I have expressed represent my true and complete professional opinions on the matters to which they refer.”

The report must be complete, objective, and drafted independently, with all material instructions and data presented candidly. Where the expert cannot provide a definitive opinion, the reasons and nature of any qualification or uncertainty must be set out.

Reports are served in accordance with the directions order; late or incomplete reports may be excluded or given less weight.

Where directed by the court, experts may be required to attend trial for oral evidence. However, especially in fast-track or lower-value cases, it is the norm for expert evidence to be given through written reports only. The threshold for allowing oral evidence is that it is necessary to assist the judge, is likely to affect the outcome, and is proportionate given the cost implications.

Exam Warning

Familiarity with the statutory and procedural requirements for expert reports, including the required content and use of statements of truth and duty acknowledgments, is critical. Incomplete or non-compliant reports may be downgraded or excluded.

Worked Example 1.5

A liability expert’s report omits the statement of truth and does not identify the literature relied upon. Can the party rely on it?

Answer:
The report does not satisfy PD 35 requirements. The court may allow defects to be remedied (e.g., by serving an amended report), but if serious or persistent, it risks exclusion or being accorded little weight, and a costs penalty may follow. Prompt corrective action and notification to both the court and opponent are essential.

Discussions Between Experts

To focus trial time and ensure agreement or clarification, CPR 35.12 permits or requires that experts (usually in the same field, instructed by different parties) hold meetings or discussions. The aims of these communications are:

To identify what is agreed and in dispute, providing the court with a summary of the expert issues.
To state concisely the points of disagreement and the experts’ reasons.
To consider if further investigations or analyses could resolve differences.
To highlight any material issues not previously raised.

Practically, these meetings are conducted without prejudice to the parties’ respective cases, and lawyers do not usually attend unless the court directs otherwise. Parties must not attempt to influence the expert’s communications or the content of the joint statement. If an expert’s view changes materially as a result of such meetings, this must be recorded in the joint statement and explained.

A signed joint statement is provided to the court and all parties. While the content of expert discussions is not to be referred to at trial unless all parties agree, any agreements reached in the course of such meetings do not bind the parties unless expressly agreed (CPR 35.12(4)-(5); PD 35 para 9.7).

Where permitted, any party may serve written questions on another party’s expert within 28 days of service of the report (CPR 35.6). Questions must be strictly for clarification, not as cross-examination. Answers must be provided within a reasonable period and, once provided, form part of the expert’s evidence. The court may restrict fees for failure to answer properly or may order answers be provided by a specified date.

Control over expert discussions and written questions is essential to managing technical evidence, clarifying differences, and ensuring effective use of expert time at trial.

Consequences of Failure to Disclose

CPR 35.13 provides explicit sanctions for failure to disclose an expert’s report: the defaulting party cannot use the report at trial, nor call the expert to give evidence, unless the court gives permission. Any variation in deadlines for service or disclosure must be obtained either by consent (where permissible) or by formal application for relief.

Once a report has been properly disclosed, any party (including the opposing one) may use it as evidence at trial unless the court orders otherwise (CPR 35.11). Thus, a report initially detrimental to its originator may be “adopted” by an opponent if it supports their case.

Applications to adduce a replacement expert after reports have been exchanged are highly regulated. The court will grant such applications only for good reason (e.g., if the original expert is demonstrably unsuitable, unable to continue due to illness, or where substantial new evidence has arisen). The court will seek to avoid prejudice, duplication, unnecessary cost, or tactical advantage, and may impose conditions such as disclosure of prior instructions and reports and appropriate apportionment of costs.

Where the directions or order stipulate that expert evidence must be limited to written reports, a party wishing to call oral expert evidence must demonstrate clearly that this is necessary, proportionate, and will genuinely aid the judge.

Concurrent oral expert evidence (“hot-tubbing”) may be directed in complex cases to facilitate side-by-side analysis of competing views.

Worked Example 1.6

A party misses the court-ordered date to serve its expert report and tries to call the expert at trial. What is the position?

Answer:
Under CPR 35.13, unless the court grants permission (via application for relief), the report cannot be used, nor can the expert be called at trial. The applicant must justify the delay, explain its impact, and propose remedial action. Relief may be possible, but costs sanctions or case management restrictions are likely.

Key Point Checklist

This article has covered the following key knowledge points:

Expert opinion is admitted only where relevant and given by a suitably qualified expert (Civil Evidence Act 1972, s.3).
The overriding duty of the expert is to the court, and this obligation takes precedence over any duty to the instructing party (CPR 35.3); experts must be impartial, act within their discipline, and disclose qualifications and limitations.
Court permission is required before an expert can be called or their report relied upon (CPR 35.4); the court is proactive in keeping expert evidence within the boundaries of necessity and proportionality (CPR 35.1).
The court can control the number of experts, the disciplines involved, the scope of issues addressed, and the format of the evidence. Use of single joint experts is common in fast-track and lower-complexity cases (CPR 35.7).
When applying for permission, a party must specify the field, the name of the expert where practicable, the relevant issues, and a cost estimate.
The content of expert reports must comply with CPR 35.10 and PD 35 para 3, including all requirements regarding the expert’s qualifications, materials relied upon, substance of instructions, factual basis, range of opinion, summary of conclusion, and compliance statements.
Written questions to experts (for clarification) can be served within 28 days of report service; answers form part of the expert’s evidence (CPR 35.6).
Experts may be required to meet for discussions and produce a joint statement; these meetings are conducted without prejudice, and joint statements must fairly represent agreements reached and note any changes of view (CPR 35.12, PD 35.9).
A failure to disclose or late service of an expert’s report means it cannot be used at trial or the expert called, except with the court’s permission (CPR 35.13). Once disclosed, any party may rely on the report (CPR 35.11).
Expert instructions are not privileged from disclosure, though the court will only allow inspection or cross-examination where it suspects inaccuracy or incompleteness and where justice requires (CPR 35.10(4), PD 35.5).
Payments to experts cannot be contingent on the outcome or the content of their report; only fair and reasonable fees and expenses are allowed to preserve integrity and objectivity.

Key Terms and Concepts

expert witness
overriding duty
single joint expert

Evidence and disclosure - Expert evidence