By Dr Richard Sawyer, Consultant in Anaesthetics and Pain Management | Experienced Expert Witness at Pain Expert.
A Single Joint Expert (SJE) is an expert instructed jointly by the parties under CPR Part 35 to provide independent opinion evidence to the court. The model is designed to reduce cost and simplify the presentation of expert evidence, particularly in lower-value litigation.
The attraction of a Single Joint Expert is obvious: a single report, shared costs, and a more streamlined evidential process. The difficulty, however, is that efficiency and control do not always sit comfortably together. Once the parties commit to a jointly instructed expert, they also accept that the expert’s opinion may become the central specialist evidence in the case.
For solicitors and litigators, the decision to instruct a Single Joint Expert is therefore not simply procedural. It is a strategic choice that may influence how the expert evidence — and sometimes the litigation itself — develops.
The Role of the Single Joint Expert
Expert evidence frequently sits at the centre of civil litigation, particularly in cases involving specialist medical or technical issues. In response to concerns about cost and proportionality, the Civil Procedure Rules encourage the use of Single Joint Experts where appropriate.
Rather than each party instructing its own expert and producing competing reports, the parties jointly instruct one specialist whose report is provided to the court. The expert’s overriding duty remains to the court rather than to the parties instructing them.
Although this approach may appear largely procedural, it alters the evidential dynamics of a case. Where only one expert report is produced, the conclusions of that report may become the primary specialist evidence before the court.
What Is a Single Joint Expert?
Under CPR Part 35.2(2), a Single Joint Expert is an expert instructed jointly by two or more parties to prepare a report for the court.
Instead of each side obtaining separate expert evidence, the parties agree upon a single specialist who addresses the relevant issues in dispute.
As with all expert witnesses, the expert’s overriding duty is to the court. The Single Joint Expert model is intended to reinforce that principle by reducing the perception that experts are aligned with the interests of the party who has instructed them and by discouraging the “hired gun” dynamic sometimes associated with competing expert reports.
Our faculty accepts Single Joint Expert pain medicine instructions across personal injury and clinical negligence, subject to conflict checks.
Why Courts Encourage Single Joint Experts
Cost control
One of the clearest advantages of appointing a Single Joint Expert is cost efficiency. Expert evidence can represent a substantial component of litigation expenditure. When each party instructs separate experts, the process often involves multiple reports, expert meetings, joint statements and, in some cases, cross-examination of competing specialists.
By contrast, a Single Joint Expert produces one report shared between the parties, with costs typically divided between them. This approach reduces duplication and supports the principle of proportionality embedded within the Civil Procedure Rules.
Procedural efficiency
The use of a Single Joint Expert can also simplify case management. With only one expert opinion before the court:
- disputes about expert methodology are less frequent
- procedural timetables are easier to coordinate
- expert meetings and joint statements may be unnecessary
- hearings may become shorter and more focused
Where the issues are relatively limited, this can significantly streamline the preparation and conduct of proceedings.
Reduced perception of partisan evidence
The SJE model also addresses long-standing concerns about the perceived adversarial nature of expert evidence. When both parties rely on the same specialist, the emphasis shifts toward independent clinical or technical analysis rather than advocacy through competing expert opinions.
A clear and balanced expert opinion may therefore narrow the issues in dispute and, in some cases, assist the parties in reaching an earlier resolution.
Proportionality in lower-value claims
For these reasons, Single Joint Experts are frequently used in fast-track and lower-value claims, particularly where:
- the issues are relatively discrete
- the relevant expertise is narrow or specialised
- competing technical interpretations are unlikely
In such cases, the SJE model can provide a proportionate and efficient approach to expert evidence.
Strategic Limitations of a Single Joint Expert
Despite these advantages, instructing a Single Joint Expert inevitably involves strategic compromises.
Loss of independent expert advice
Where each party instructs its own expert, lawyers can explore alternative interpretations of the evidence and test competing hypotheses in confidence. That opportunity largely disappears once a Single Joint Expert is appointed. The jointly instructed report may become the only specialist opinion available to both the parties and the court.
Risk of an unfavourable opinion
Because the Single Joint Expert’s report may be the only expert evidence before the court, its conclusions can carry considerable weight. If the opinion proves adverse to one party’s case, there may be limited scope to counterbalance it through competing expert analysis.
In practice, this may:
- weaken a party’s negotiating position
- narrow the issues that can realistically be contested
- increase pressure to resolve the claim
Limited scope to challenge the expert
The Civil Procedure Rules permit written questions to be put to an expert under CPR Part 35.6, and cross-examination may occur where necessary. However, without competing expert opinions to highlight differences in professional judgement, the scope for challenging an SJE’s reasoning may be more limited.
Negotiation of the letter of instruction
A further practical issue arises at the outset of the process. Because the expert is instructed jointly, the letter of instruction must be agreed between the parties. This may require careful negotiation regarding the issues to be addressed and the material provided to the expert.
In some circumstances, strategic nuance may be diluted as the wording of the instructions is refined in order to achieve agreement between opposing parties.
When a Single Joint Expert May Be Unsuitable
The Single Joint Expert model is not appropriate in every dispute.
In complex, high-value, or technically contested litigation, competing expert evidence may assist the court by testing different interpretations of the evidence. Independent experts can help the court evaluate where professional judgment may legitimately differ.
For this reason, multi-track claims frequently involve separate experts instructed by each party. Where the issues are particularly complex, the evidential value of independent expert analysis may outweigh the procedural efficiencies offered by a jointly instructed expert.
The Importance of Expert Independence
Whether jointly instructed or retained by a single party, the expert’s overriding duty remains unchanged: to assist the court impartially.
Courts rely heavily on medical and technical experts not only to interpret specialist evidence but also to contextualise clinical findings and explain how a particular presentation compares with similar cases encountered in professional practice.
A carefully reasoned and balanced expert opinion can therefore have a significant influence on how a case is understood.
Conclusion
A Single Joint Expert represents an important procedural tool within modern civil litigation. When used appropriately, the model can reduce costs, streamline proceedings and focus the issues that require determination by the court.
At the same time, the model involves clear strategic trade-offs. By relying on a single expert, parties relinquish the opportunity to obtain confidential expert advice and to test competing professional opinions.
The key question for litigators is therefore not simply whether a Single Joint Expert is available, but whether the nature of the dispute makes that approach appropriate. In cases where the issues are limited and the value of the claim modest, a jointly instructed expert may provide a proportionate and efficient solution. In more complex disputes, however, the evidential value of independent expert analysis may justify the additional cost and procedural complexity of instructing separate experts.
If You’re a Legal Professional
Instructing a Single Joint Expert in a pain medicine case? Our faculty accepts SJE appointments with the same evidential rigour as any single-party instruction.
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FAQs
What is a Single Joint Expert in civil litigation?
A Single Joint Expert is an expert instructed jointly by two or more parties under CPR Part 35 to provide independent expert evidence to the court.
Why do courts encourage Single Joint Experts?
They help control litigation costs, reduce duplication of expert evidence and streamline proceedings.
Can a Single Joint Expert be challenged?
Yes. Parties may put written questions to the expert under CPR Part 35.6, and the expert may be cross-examined at trial if necessary.
When might a Single Joint Expert be inappropriate?
SJEs may be unsuitable in complex or high-value disputes where competing expert opinions would assist the court.
Who pays for a Single Joint Expert?
The costs of a Single Joint Expert are usually shared between the parties unless the court directs otherwise.
