Guide
Single joint expert or party appointed: the cost consequences
Updated
This decision changes the fee more than any other single choice in an expert instruction, and it also changes what you are entitled to expect from the expert.
What the rules provide
CPR rule 35.7(1) provides that where two or more parties wish to submit expert evidence on a particular issue, the court may direct that the evidence on that issue is given by a single joint expert, and rule 35.7(2) allows the court to select the expert if the parties cannot agree. Rule 35.8 governs instructions to a single joint expert: any relevant party may give instructions, but must at the same time send a copy to the other relevant parties. The court may give directions about payment of the expert's fees and expenses, may limit the amount payable before the expert is instructed, and may direct that some or all of the parties pay that amount into court. Unless the court otherwise directs, the relevant parties are jointly and severally liable for the fees and expenses (justice.gov.uk).
The comparison
| Point | Single joint expert | Party appointed expert |
|---|---|---|
| Number of reports | One | One per party, plus a discussion between experts if the court directs one |
| Total cost to the dispute | Lower, because the records are reviewed once | Higher, because the same material is analysed twice and the differences then have to be narrowed |
| Cost to you individually | Usually a share, subject to the court's directions | Your own expert's fee in full, plus costs risk on the outcome |
| Liability for the fee | Under rule 35.8(5), the relevant parties are jointly and severally liable unless the court directs otherwise | The instructing party is liable to its own expert |
| Control of the instruction | Shared. Any relevant party may instruct, copying the others | Yours, within the limits of the expert's duty to the court |
| Where it usually fits | Family proceedings, lower value matters, and issues where the range of respectable opinion is narrow | Higher value disputes and issues where valuation methodology or professional judgment is genuinely contested |
| Communication with the expert | Copied to all relevant parties | Direct, subject to disclosure of the substance of instructions under rule 35.10(3) |
The trade off, stated plainly
A single joint expert is cheaper and, in most matters, sufficient. It stops being sufficient where the issue turns on a methodological choice on which competent professionals genuinely differ, because a single report presents one such choice as the answer. The honest test is whether you would be arguing about the method or about the arithmetic. Arithmetic does not need two experts. Method sometimes does, and where the sum in dispute is large enough to justify it, the additional cost can be rational.
Controlling the cost of a joint instruction
- Agree the questions jointly before instructing, so the expert is not reconciling two different briefs.
- Ask the court to limit the amount payable under rule 35.4(4) where the fee is disproportionate to the issue.
- Use rule 35.6 written questions properly. They are for clarification, and using them as cross-examination in writing generates fees on both sides.
- Establish disclosure before the expert starts, not while they are working.
Rule 35.10(3) requires an expert's report to state the substance of all material instructions, whether written or oral, on the basis of which it was written, and rule 35.10(4) provides that those instructions are not privileged against disclosure. That applies to party appointed experts as much as to joint ones.