Evidence and disclosure - Single joint experts and expert di...

Learning Outcomes

This article outlines the rules and procedures governing single joint experts (SJEs) and expert discussions in civil litigation under CPR Part 35, equipping you to tackle SQE1 FLK1 assessment questions on expert evidence. It explains when the court is likely to direct the use of an SJE, when separate experts may still be appropriate, and how proportionality, complexity and divergent opinion influence that decision. It details the overriding duty owed by experts to the court, the core content, statement of truth and verification requirements for expert reports, and the court’s permission regime for expert evidence, including defining issues and estimating costs. It examines the mechanisms for questioning experts in writing, the time limits and sanctions under CPR 35.6, and the court’s control of oral expert evidence, particularly in fast-track and multi-track cases. It also discusses the purpose, procedure and outcomes of expert discussions, the preparation and status of joint statements, and the interaction between SJEs and party-appointed experts. Finally, it reviews the disclosure obligations for expert reports, the consequences of non-disclosure under CPR 35.13, and how these rules shape effective, exam-focused analysis of case management and litigation strategy.

SQE1 Syllabus

For SQE1, you are required to understand the court's approach to expert evidence, particularly in managing costs and promoting efficiency through single joint experts and expert discussions, with a focus on the following syllabus points:

• The court's power to direct the use of a single joint expert (CPR 35.7).
• The overriding duty of experts to the court (CPR 35.3).
• The purpose and procedure for discussions between experts (CPR 35.12).
• The requirements and status of joint statements prepared by experts following discussions (CPR 35.12(3)).
• The potential costs consequences relating to expert evidence and discussions.
• The permission regime for expert evidence, including identifying the expert’s field/issues and providing a costs estimate when seeking permission (CPR 35.4).
• The process and limits for written questions to experts, including time limits and possible sanctions if answers are not provided (CPR 35.6).
• The content requirements and statement of truth for expert reports (PD 35 paras 3.1–3.2, CPR 35.10).
• The court’s control of oral expert evidence and concurrent evidence where appropriate, with written reports being the default in fast-track cases (CPR 35.5; PD 28; PD 29).

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.

1. Under CPR Part 35, to whom does an expert witness owe their primary duty?
   1. The party instructing them
   2. The court
   3. The party paying their fees
   4. Both parties jointly
2. Which of the following factors will the court consider when deciding whether to direct the use of a single joint expert?
   1. The value of the claim
   2. The complexity of the issue requiring expert evidence
   3. Whether the parties have already instructed their own experts
   4. All of the above
3. What is the primary purpose of discussions between experts under CPR 35.12?
   1. To decide which expert's opinion is correct
   2. To prepare questions for cross-examination
   3. To identify and narrow the issues on which they agree/disagree
   4. To agree on the final amount of damages

Introduction

Expert evidence plays an essential role in civil litigation where technical or specialist knowledge is required to assist the court in understanding complex issues. The Civil Procedure Rules (CPR) provide a framework for managing expert evidence, aiming to ensure it is restricted to that which is reasonably required to resolve the proceedings (CPR 35.1). Two key mechanisms within this framework are the use of single joint experts (SJEs) and structured discussions between experts instructed by opposing parties. This article examines the rules governing SJEs and expert discussions, highlighting their practical implications for case management and costs.

The court strictly manages expert evidence, often from the directions stage, and will only grant permission to rely on experts when it is reasonably required for resolving the issues in dispute. When permission is sought, parties must identify the expert’s field and the specific issues to be addressed, the proposed expert (where practicable), and provide an estimate of the costs of the expert evidence (CPR 35.4). Typically, expert evidence is given in writing; in the fast track, oral expert evidence will only be allowed if necessary in the interests of justice (CPR 35.5; PD 28). In the multi-track, the court may permit oral expert evidence and can, where appropriate, direct concurrent expert evidence (“hot-tubbing”) to focus and streamline expert issues. Pre-action protocols and the Practice Direction on Pre-Action Conduct and Protocols also encourage the early, proportionate use of expert input—including consideration of a single joint expert—to help narrow disputes and reduce cost.

Key Term: Single Joint Expert (SJE)
An expert instructed to prepare a report for the court on behalf of two or more of the parties (including the claimant) to the proceedings (CPR 35.2(2)).

Single Joint Experts (SJEs)

An SJE is an expert instructed to prepare a report for the court on behalf of two or more parties involved in the proceedings. This approach contrasts with the traditional method where each party instructs their own expert.

Appointment of an SJE

The court has the power to direct that evidence on a particular issue should be given by an SJE (CPR 35.7(1)). This power reflects the court's duty under the overriding objective to deal with cases justly and at proportionate cost. The court will consider various factors when deciding whether to direct the use of an SJE, including:

• The proportionality of instructing separate experts relative to the amount in dispute, the importance of the issue, and its complexity (PD 35 para 7(a)).
• Whether instructing an SJE is likely to assist resolution more speedily and in a more cost-effective way than separate experts (PD 35 para 7(b)).
• Whether expert evidence concerns liability, causation, or quantum (PD 35 para 7(c)).
• Whether the issue falls within a substantially established area of knowledge where a range of opinion is unlikely, or whether diverse schools of thought make a single opinion inadequate (PD 35 para 7(d)).
• Whether a party has already instructed an expert (including at pre-action stage) and whether questions to that expert might remove the need for the other party to instruct another expert (PD 35 para 7(e)).
• Whether questions put to a single joint expert may not conclusively deal with all issues requiring testing before trial (PD 35 para 7(f)).
• Whether a conference with legal representatives, experts and other witnesses is required, making a single joint expert impractical (PD 35 para 7(g)).
• Whether privilege issues make instruction of a single joint expert inappropriate (PD 35 para 7(h)).

Permission for expert evidence is required (CPR 35.4). When seeking permission, parties must identify the field and issues, provide the expert’s name where practicable, and estimate the costs. The court may specify the expert issues and limit the scope of expert involvement. In fast-track cases, the default approach is to appoint an SJE unless there is a good reason not to do so (PD 28 para 3.9(4)). In multi-track cases, especially where complex issues or significant divergent schools of opinion exist, the court may permit separate experts.

Parties are encouraged to agree on the appointment of an SJE where appropriate. If they cannot agree, the court may select the expert from a list prepared by the parties or direct an alternative selection method (CPR 35.7(2)).

Worked Example 1.1

In a fast-track claim valued at £18,000 concerning allegedly defective plumbing installation, the main technical issue relates to the standard of workmanship. Both parties indicate in their directions questionnaires that they wish to rely on expert plumbing evidence. What approach is the court likely to take regarding expert evidence?

Answer:
The court is likely to direct that the plumbing evidence be given by a single joint expert. Fast-track cases generally favour the use of SJEs for reasons of proportionality and cost-effectiveness (PD 28 para 3.9(4)), especially where the issue relates to a standard assessment like workmanship quality.

Worked Example 1.2

A multi-track Technology and Construction Court claim raises complex geotechnical causation issues about subsidence. The parties each propose their own geotechnical expert and identify that there are different accepted methodologies within the field. Should the court appoint an SJE?

Answer:
Likely not. Where the issue sits within a field with recognised divergent methodologies or a range of expert opinion, separate experts are usually more appropriate so the differing schools of thought can be tested at trial. An SJE might be insufficient to capture and fairly explore the range of opinion (PD 35 para 7(d)).

Instructions and Reporting

Instructions to an SJE should ideally be agreed jointly by the parties. If agreement cannot be reached, the parties should provide separate instructions, which should then be copied to the other instructing parties (PD 35 para 9.8). The expert’s duty is to the court, overriding any duty to the instructing party; the expert must provide objective, independent opinion on matters within their field (CPR 35.3).

Expert reports must comply with CPR 35.10 and PD 35 paras 3.1–3.2. They should:

• State the expert’s qualifications and experience.
• Identify the literature or other materials relied on.
• Set out the substance of all facts and instructions material to the opinions expressed, distinguishing facts within the expert’s own knowledge.
• Describe examinations, measurements, tests or experiments relied upon, who performed them, their qualifications, and whether they were under the expert’s supervision.
• Summarise any range of opinion on the matters dealt with and give reasons for the expert’s own opinion.
• Provide a summary of conclusions and any necessary qualifications.
• Include a statement confirming understanding of and compliance with the expert’s duty to the court and awareness of CPR 35 and the Guidance for the Instruction of Experts in Civil Claims.
• Be verified by the expert’s statement of truth.

Letters of instruction to experts are not privileged. However, the court will not order disclosure of the instructions or allow cross-examination on them unless satisfied there are reasonable grounds to consider the expert’s statement of instructions in the report to be inaccurate or incomplete (PD 35 para 5; CPR 35.10(4)). After exchange, it is common for parties to send the other side’s expert report to their own expert for comment.

In fast-track cases, written reports are usually relied upon at trial; oral evidence will be allowed only if necessary in the interests of justice (CPR 35.5). In multi-track cases, the court may allow oral expert evidence and can direct concurrent expert evidence where useful to focus the real points in dispute.

Worked Example 1.3

The defendant believes the claimant’s expert has omitted a significant instruction that might affect the opinion expressed. Can the defendant cross-examine on the expert’s instructions?

Answer:
Only if the court is satisfied there are reasonable grounds to consider that the statement of instructions in the report is inaccurate or incomplete. Without that threshold, the court will not permit cross-examination on instructions (PD 35 para 5; CPR 35.10(4)).

Questioning an SJE

Any party can put written questions to the SJE about their report within 28 days of service (CPR 35.6(2)). These questions must be proportionate and for clarification purposes only. The expert’s answers are treated as part of their report. Questions must be copied to all parties. If an expert does not answer proper questions, the court may make appropriate orders—including restricting reliance on the report—and the expert’s fees for answering questions may be treated as irrecoverable if the questions are non-compliant or disproportionate (CPR 35.6(4)).

Worked Example 1.4

Following service of an SJE report, the claimant sends focused clarification questions within 28 days but the expert does not respond. What might the court do?

Answer:
The court can order the expert to answer and may, in appropriate cases, restrict reliance on the report until answers are provided or treat related fees as irrecoverable. Persistent failure could lead to case management sanctions to ensure the overriding objective is met (CPR 35.6(4)).

Advantages and Disadvantages

Using an SJE can lead to significant cost savings and reduce the adversarial nature of expert evidence. It also tends to speed up proceedings by removing duplication. However, a party may feel that the SJE's opinion does not fully reflect the nuances of their case or disagree with the conclusions. Where a range of expert opinion exists, or the issues are complex and contested, an SJE may not be appropriate. The court is wary of appointing an SJE where privilege issues arise (for example, where expert communications need to remain confidential), or where the case needs a conference involving legal representatives and witnesses that an SJE structure cannot accommodate.

In such situations, a party may seek the court's permission to instruct their own expert even after an SJE has reported, but permission will only be granted if there is a good reason—for instance, where the SJE has moved outside their field, overlooked relevant materials, or where fresh, material evidence emerges. In personal injury practice, note the distinction between an agreed expert in the pre-action phase and an SJE within proceedings: an agreed expert is not jointly instructed; the other party may still instruct their own expert later if dissatisfied with the agreed expert’s views.

Worked Example 1.5

An SJE’s report is adverse to the defendant. The defendant’s advisers obtain a short review from a specialist indicating the SJE used an outdated methodology. Can the defendant seek permission to rely on their own expert?

Answer:
Potentially, yes. If the defendant can show a good reason—such as the SJE applying outdated or unsuitable methodology or new material coming to light—the court may grant permission for a party-specific expert despite the earlier SJE direction. The court will weigh proportionality and necessity and may limit scope to defined issues.

Exam Warning

Remember that while the use of an SJE is encouraged, particularly in lower-value or less complex cases, it is not mandatory in all circumstances. The court retains discretion, and factors like the complexity of the issue or a significant divergence in potential expert opinion might justify separate experts, especially in multi-track cases.

Expert Discussions

Where parties have instructed separate experts, the court often directs those experts to hold discussions.

Key Term: Expert Discussion
A meeting or communication between experts instructed by different parties in proceedings, aimed at identifying and narrowing issues and reaching agreed opinions where possible (CPR 35.12).

Purpose of Discussions

The primary purposes of expert discussions, as outlined in CPR 35.12(1), are for the experts to:

• Identify and discuss the expert issues in the proceedings.
• Reach agreed opinions on those issues where possible.
• If they cannot reach agreement on an issue, narrow the scope of disagreement.

Discussions are intended to assist the court by clarifying the expert evidence and focusing on the key points of contention, thereby saving court time and costs. The court may specify the issues the experts must discuss.

Procedure

The court may specify the issues the experts must discuss. Parties and their legal representatives should cooperate to produce an agenda for the discussion if necessary, ensuring it is focused and neutral (PD 35 para 9.2 & 9.3). The agenda must not be framed as leading questions or hostile prompts; it should instead list topics neutrally. Legal representatives must not attend the discussions unless all parties agree or the court orders it (PD 35 para 9.4). The discussions are generally “without prejudice” and cannot be referred to at trial unless the parties agree (CPR 35.12(4)). Experts can request directions from the court where needed, provided they notify all parties before doing so.

Key Term: Without Prejudice
A legal principle meaning that statements made in a genuine attempt to settle a dispute cannot usually be put before the court as evidence of admissions against the interest of the party that made them.

Joint Statement

Following their discussions, the experts must prepare a joint statement for the court (CPR 35.12(3)). This statement must record:

• The issues on which they agree.
• The issues on which they disagree, including a summary of their reasons for disagreement.

Key Term: Joint Statement
A written statement prepared by experts following their discussions, detailing the issues on which they agree and disagree, submitted to the court (CPR 35.12(3)).

The joint statement must be signed by the experts within 7 days of the discussion and provided to the parties within 14 days of signing (PD 35 para 9.6). The experts do not need the parties' authority to sign the statement (PD 35 para 9.7). If an expert significantly alters an opinion as a result of the discussion, the joint statement should include a note or addendum explaining the change and the reasons. Any agreement reached between experts during discussions does not bind the parties unless they expressly agree to be bound (CPR 35.12(5)).

The joint statement is a key case management tool. Judges often use it to set the structure for expert evidence at trial, focus cross-examination, and identify whether any expert issues can be treated as common ground.

Revision Tip

The joint statement is an essential document. It helps the court understand the expert evidence and can significantly narrow the issues for trial. Pay close attention to its requirements and implications when advising clients or preparing for hearings.

Worked Example 1.6

In a multi-track clinical negligence claim, the Claimant (C) and Defendant (D) have each instructed their own orthopaedic expert. The court directs the experts to hold discussions and prepare a joint statement. Following discussions, the experts agree on the nature of C's injury but disagree fundamentally on whether D's actions fell below the required standard of care (breach of duty). What should the joint statement contain?

Answer:
The joint statement should clearly state that the experts agree on the nature of C's injury (specifying the agreed points). It must then clearly state that they disagree on the issue of breach of duty and provide a summary of the reasons given by each expert for their differing opinions on this critical issue.

Worked Example 1.7

During expert discussions in a quantum dispute, the claimant’s accountant revises their opinion after reviewing the defendant’s expert’s spreadsheet, reducing the claimed future loss. How should this be recorded?

Answer:
The joint statement should include a note or addendum explaining the change of opinion and the reasons for it (PD 35 para 9.7). The revised opinion becomes part of the agreed position or narrowed disagreement, as relevant.

Worked Example 1.8

The defendant’s counsel asks to attend the experts’ meeting to “ensure focus” on the right issues. The claimant objects. What is the likely outcome?

Answer:
Legal representatives should not attend expert discussions unless all parties agree or the court orders attendance (PD 35 para 9.4). Without agreement or a specific court order, counsel should not attend. The parties should instead agree a neutral agenda.

Interaction Between SJEs and Expert Discussions

It is important to note that expert discussions under CPR 35.12 are designed for situations where parties have instructed separate experts. If an SJE has been appointed for a particular issue, there would typically be no need for expert discussions on that specific issue, as there is only one expert opinion before the court. However, a case might involve both an SJE on one issue and separate experts (requiring discussions) on other issues. For example, in personal injury litigation, an SJE might address medical causation while party-specific experts address complex loss of earnings and pension issues. The court will tailor directions to ensure expert involvement remains proportionate and focused.

Where separate experts are instructed, the court will often combine directions for exchange of reports, written questions, expert discussions, and a joint statement timetable. The joint statement will then be used to set the order and scope of expert evidence at trial; the judge may, if appropriate, direct concurrent evidence to address issues systematically.

Finally, be aware of disclosure obligations. Under CPR 35.13, a party who fails to disclose an expert’s report may not use the report at trial or call the expert to give evidence orally unless the court gives permission. This underlines the need to comply with expert directions and ensure timely exchange and disclosure.

Worked Example 1.9

The defendant fails to disclose their engineering expert’s report by the ordered date. At trial, can they rely on the expert?

Answer:
Not without the court’s permission. CPR 35.13 provides that a party who fails to disclose an expert’s report may not use the report at trial or call the expert to give evidence orally unless the court gives permission. The court will consider the reasons for default, prejudice, and proportionality.

Key Point Checklist

This article has covered the following key knowledge points:

• The court can direct parties to use a Single Joint Expert (SJE) to provide evidence on a specific issue (CPR 35.7).
• The decision to appoint an SJE considers proportionality, cost-effectiveness, and the nature of the dispute, including whether a range of opinion exists (PD 35 para 7).
• Experts, including SJEs, owe an overriding duty to the court (CPR 35.3) and must comply with report content and verification requirements (CPR 35.10; PD 35 paras 3.1–3.2).
• Permission to rely on expert evidence must identify the expert’s field/issues, name (where practicable), and include a costs estimate (CPR 35.4).
• Parties can put written questions to an SJE or any expert for clarification within 28 days of service; answers form part of the report and sanctions may follow if proper questions are not answered (CPR 35.6).
• Where separate experts are instructed, the court often directs them to hold discussions to identify areas of agreement and disagreement (CPR 35.12), using a neutral agenda without legal representatives unless agreed or ordered (PD 35 para 9.2–9.4).
• Discussions between experts are generally without prejudice (CPR 35.12(4)); any agreement reached does not bind the parties unless expressly agreed (CPR 35.12(5)).
• Following discussions, experts must prepare and sign a joint statement within 7 days and provide it to parties within 14 days, noting any change of opinion (CPR 35.12(3); PD 35 para 9.6–9.7).
• A party who fails to disclose an expert’s report may not use it or call the expert without the court’s permission (CPR 35.13).
• In fast-track claims, written expert reports are the default; oral evidence will be allowed only if necessary. The court can direct concurrent expert evidence in appropriate multi-track cases.

Key Terms and Concepts

• Single Joint Expert (SJE)
• Expert Discussion
• Without Prejudice
• Joint Statement