A single joint expert (SJE) is one expert instructed jointly by two or more parties in a legal case, rather than each side bringing in its own. The expert prepares a single report that goes to the whole court, and both parties rely on it rather than commissioning competing opinions.
Prof. Sandip Hindocha, National Lead Forensic Medical Examiner and a member of the Faculty of Forensic & Legal Medicine, is regularly instructed as a single joint expert in medical negligence, personal injury, and scarring cases.
In short: a single joint expert is appointed by agreement between the parties (or, if they can’t agree, by the court) to give one report that both sides use. It’s the norm on the small claims and fast tracks, common on the multi-track for straightforward issues, and governed by CPR 35.7 and 35.8.
Either party can send instructions as long as the other side is copied in, fees are usually split jointly and severally, and a party unhappy with the report can, in limited circumstances, apply for permission to get a second opinion.
What a Single Joint Expert Actually Is
Under the Civil Procedure Rules, a single joint expert is an expert instructed to prepare a report for the court on behalf of two or more parties to the proceedings, including the claimant. That’s a narrower thing than it sounds.
The court doesn’t appoint the expert itself and doesn’t select them from a panel. The parties instruct and pay the expert between them, the court’s role is simply to direct that one expert should be used on a particular issue, instead of each side bringing its own.
This matters because people sometimes assume a single joint expert is “the court’s expert” and therefore automatically neutral in a way a party-appointed expert isn’t.
Every expert instructed under CPR Part 35, joint or not, owes an overriding duty to the court rather than to whoever is paying them. The difference with an SJE is procedural: one report, shared instruction, shared cost, rather than who the expert answers to.
Why Courts Encourage a Single Joint Expert
The Civil Procedure Rules actively encourage the use of a single joint expert, particularly on smaller claims, to keep litigation proportionate. Where a case is allocated to the small claims track or the fast track, permission for expert evidence on a given issue will usually be limited to one expert.
The reasoning is straightforward: if both sides agree on the underlying facts (the nature of an injury, the standard of care, the value of a repair), there’s often no real need to pay for two experts to say broadly the same thing at twice the cost.
On the multi-track, where claims tend to be higher value or more contested, single joint experts are still common but not automatic.
Courts are more willing to allow each party its own expert witness where the issue is genuinely in dispute or central to liability, and less willing where the point is technical but not seriously contested.
| Track | Typical Expert Approach |
|---|---|
| Small claims | A single joint expert is normally required, if permission for expert evidence is given at all |
| Fast track | A single joint expert is the default position on most issues |
| Multi-track | A single joint expert is common for discrete or uncontested issues; separate experts are more likely where the issue is genuinely disputed |
How a Single Joint Expert Is Instructed
Once the court has directed that a single joint expert be used, CPR 35.7 and 35.8 set out the mechanics. Any relevant party can send instructions to the expert, but must send a copy to the other party or parties at the same time.
In practice, solicitors usually try to agree a single, joint letter of instruction rather than sending separate ones, since a joint letter avoids the expert receiving two subtly different briefs. Prof. Hindocha sets out what a joint letter of instruction should cover on the instruction page.
Either party can also put written questions to the expert about the report under CPR 35.6, for clarification rather than to argue the point.
If the parties can’t agree who the expert should be, the court can select from a list the parties have put forward, or direct another way of choosing.
| Rule | What It Covers |
|---|---|
| CPR 35.6 | The right to put written questions to an expert about their report, for clarification only |
| CPR 35.7 | The court’s power to direct that expert evidence on an issue is given by a single joint expert |
| CPR 35.8 | How a single joint expert is instructed, including the requirement to copy the other party |
Who Pays the Expert’s Fees
Unless the court directs otherwise, the parties are jointly and severally liable for the single joint expert’s fees and expenses. In practice this usually means the cost is split.
That said, “jointly and severally” also means the expert can, if necessary, recover the full fee from either party and leave them to sort out the split between themselves.
Where a party asks the expert written questions under CPR 35.6, that party generally pays for the expert’s time in answering them, though the court can revisit who bears that cost later in the case.
What Happens If You Disagree With the Report
This is usually the real question behind the search. A single joint expert’s report can be difficult to challenge, because it’s often the only expert evidence before the court on that issue.
If a party has genuine, non-trivial concerns, the leading case is Daniels v Walker [2000] 1 WLR 1382, in which the Court of Appeal held that a party can apply for permission to obtain a second expert opinion where their reasons for wanting one are not “fanciful.”
That’s a real but limited safeguard: permission is at the court’s discretion, it isn’t granted simply because a party dislikes the outcome, and even where a second report is obtained there’s no guarantee the court will let it be relied on at trial.
Before applying for a second opinion, it’s usually worth putting written questions to the existing expert first under CPR 35.6, since a clarification is quicker, cheaper, and more likely to succeed than a fresh instruction.
Single Joint Expert vs Party-Appointed Expert
| Single Joint Expert | Party-Appointed Expert | |
|---|---|---|
| Instructed by | Both or all parties jointly | One party only |
| Report goes to | The whole court and all parties | The instructing party, then disclosed if relied on |
| Typical use | Small claims, fast track, straightforward issues | Multi-track, contested or high-value issues |
| Cost | Usually shared, jointly and severally | Paid by the instructing party |
| Challenging the opinion | Requires the court’s permission (Daniels v Walker) | Met with the other side’s own expert evidence |
Frequently Asked Questions
Is a single joint expert the same as an independent expert? Every expert instructed under CPR Part 35 is independent in the sense that they owe their overriding duty to the court, not to whoever pays them, whether they’re a single joint expert or instructed by one party alone.
“Single joint” describes who instructs and pays the expert, not how independent their opinion is.
Can I choose my own expert instead of a single joint expert? Only if the court agrees. Where the court has directed a single joint expert on a given issue, a party generally can’t simply instruct a rival expert instead.
If there’s a good reason to want a second opinion, the route is to apply to the court, as set out in Daniels v Walker, rather than to instruct one unilaterally.
What happens if the parties can’t agree who the single joint expert should be? Each side can put forward names, and if there’s no agreement the court will choose, either from a list the parties provide or by another method the court directs.
Can a single joint expert be cross-examined at trial? Yes, although it’s less common than with party-appointed experts, since there’s usually no competing expert evidence to test the report against.
A party can still put written questions to the expert before trial, and in some cases the court will permit the expert to give oral evidence and be questioned.
Does a single joint expert favour either side? No. The expert’s duty is to the court, not to whichever party first suggested their name or paid the larger share of the fee. A properly conducted single joint expert report should read the same regardless of which party is more or less happy with the conclusion.
Prof. Hindocha is regularly instructed as a single joint expert in medical negligence, personal injury, and scarring and disfigurement cases, and prepares reports fully compliant with CPR Part 35. To discuss instructing him, either jointly or on behalf of one party, get in touch.
This article is general information about how single joint experts work under the Civil Procedure Rules and is not a substitute for legal advice on a specific case.