Single joint expert

Need an independent opinion — on a boiler, a used car, a botched repair — to make your case? On the small claims track, the court usually expects both sides to share one expert rather than pay for two.

Can I instruct my own expert instead of sharing one?

Only with the court's permission. On the small claims track, if expert evidence is allowed at all, the court will normally direct a single joint expert rather than allow each side to bring their own — separate experts are the exception, not the default, because of the cost and complexity they add to a low-value dispute.

Who chooses the single joint expert?

Ideally both parties agree on the expert together. If you cannot agree, each side can put forward a shortlist and the court will select from those, or select an expert itself. Once instructed, the expert works for the court, not for either party individually.

Who pays for the single joint expert?

Unless the court orders otherwise, both parties are jointly and severally liable for the expert's fees and expenses — meaning the expert can pursue either party for the whole fee, though it is usually split and each side pays their agreed share upfront.

Can I ask the expert questions about their report?

Yes. Once a single joint expert has produced a report, either party can put written questions to them about it, provided this is done for the purpose of clarifying the report rather than reopening the whole assessment. The expert's answers become part of the evidence.

What if I disagree with the single joint expert's conclusions?

You can challenge the report through written questions, and in some cases apply to the court for permission to call a second expert if there is a genuine and material dispute the joint report has not resolved. Courts grant this sparingly, since it defeats much of the cost-saving purpose of a shared expert.

Does the single joint expert attend the hearing?

Not usually on the small claims track. Their written report is normally sufficient evidence in itself, and the case is decided on the papers plus the parties' own evidence, without the expert needing to give oral evidence in person.

Can the single joint expert be cross-examined at trial?

On the small claims track this is unusual, since cases are normally decided on the papers and the parties' own evidence without oral expert evidence. On tracks where oral evidence is more common, a joint expert can occasionally be asked to attend and answer questions, though this remains the exception rather than the rule.

Why courts prefer one expert on small claims

No party can call an expert, or put an expert's report in evidence, without the court's permission — expert evidence is restricted to what is reasonably required to resolve the case. On the small claims and fast tracks, where the sums at stake are modest, the court will normally give that permission only for evidence from a single expert on a given issue, shared between the parties, rather than allow each side to instruct its own.

The reasoning is proportionality: two competing experts on, say, whether a used car had a pre-existing fault can easily cost more in fees than the claim itself is worth. A single joint expert keeps the cost of resolving a technical dispute in line with the value of the dispute.

How instructions and costs work

Ideally, both parties agree who the expert should be and jointly draft the letter of instruction, setting out the questions the expert is being asked to answer. Where parties cannot agree on an expert, each can suggest names and the court will choose from the list, or select an expert of its own.

Both parties are usually jointly and severally liable for the expert's fees unless the court directs otherwise — in practice this normally means splitting the cost upfront in agreed shares. The expert owes their duty to the court, not to whichever party happens to be paying their share, and must keep both sides equally informed throughout, including sending the finished report to both parties at the same time.

If you disagree with the report

A single joint expert's report is not automatically the final word. Either party can put written questions to the expert seeking clarification of anything in the report, and the expert's answers then form part of the evidence in the case. In genuinely contested cases, a party can apply for permission to instruct a second, separate expert — but courts grant this only where there is a real and material dispute the joint report has not settled, since it undermines the cost-saving purpose of sharing an expert in the first place.

When a single joint expert is not appropriate

A shared expert is the norm on the small claims track, but it is not universal. Where a case has been allocated to the fast or multi-track because of its value or complexity, or where the parties' positions are so far apart that a single opinion is unlikely to resolve the real dispute between them, the court has discretion to permit each side its own expert instead.

Even then, permission is not automatic — a party asking to depart from the single joint expert default needs to explain to the court why a shared expert would not be adequate, and be ready to justify the extra cost that separate experts bring to a case of modest value.

A tenant sues a builder for £3,800 over an allegedly faulty boiler installation. Both sides accept the dispute turns on whether the installation met the relevant safety standard — a technical question neither party nor the court can resolve without expert help. The court gives permission for expert evidence and directs a single joint expert. The parties agree a heating engineer from a shortlist, split the £450 fee equally, and jointly instruct him to answer three specific questions. His written report goes to both sides on the same day and is used, alongside the parties' own evidence, to decide the case.

Case management conference

Civil Procedure Rules, Part 35

Guidance for the instruction of experts in civil claims

Single Joint Expert — Small Claims Glossary

What a single joint expert is, why small claims courts direct one shared expert instead of two, and how instructions and fees are split.