Mann v Messrs Chetty & Patel

When deciding whether to permit expert evidence, the court must assess its likely cogency, usefulness in resolving the issues, and cost in relation to the sums at stake. Proportionality is not assessed merely by comparing the proposed costs with the claimant’s best-case recovery. The court may consider the broad range of likely recovery, while avoiding premature determination of the merits. Expert evidence may be limited in scope, jointly instructed, and subject to a time or cost limit. In retrospective professional-negligence litigation, evidence relevant to the original proceedings must be distinguished from evidence relevant to assessing the loss caused by the alleged negligence.

The appellant sued his former solicitors for alleged negligence in conducting his application for ancillary relief in divorce proceedings. The county court permitted amendments to the claim but refused permission for expert evidence concerning the former matrimonial home, the parties’ former business, and alleged forged signatures on share-transfer documents.

The appeal concerned the exercise of case-management discretion under the Civil Procedure Rules. The central questions were whether the proposed evidence was sufficiently cogent and useful, and whether its cost was proportionate to the claim and the issues requiring determination.

1. Appeal allowed in part. The court affirmed that intervention in a case-management decision is justified only where the judge erred in principle or the result of the balancing exercise was plainly wrong.
2. Under the overriding objective and the expert-evidence provisions of the Civil Procedure Rules, the court had to assess:
   • the likely cogency of the proposed evidence;
   • its usefulness in resolving the issues; and
   • its cost and relationship to the sums at stake.
3. The question whether the solicitor had been negligent in the original ancillary-relief proceedings was distinct from the question of what loss the appellant had suffered. The former depended principally on the practice guidance applicable at the time, including the guidance in Evans v Evans [1990] 1 FLR 319. The latter concerned what the court might have achieved had the case been properly prepared.
4. In assessing proportionality, the judge could consider the broad ambit of likely recovery if the claimant established the relevant factual allegations. The judge was not required simply to accept the pleaded best-case value. However, the judge had misunderstood the full amount claimed and had insufficient evidence about the actual cost of the proposed evidence.
5. Permission for a retrospective valuation of the home and handwriting evidence was rightly refused because the evidence had limited cogency or significance. Evidence concerning the business was different. Given the centrality of the business dispute, a limited report by a jointly instructed accountant was reasonably required. It should comment on the existing accountant’s opinions, scrutinise the available accounts, interview the wife if possible, and be subject to a time limit no greater than that proposed by the accountant.
6. Lady Justice Hale gave the principal judgment. Lord Justice Nourse agreed with her reasons. The order was made in the agreed terms.

• Court of Appeal (Civil Division): Mann v Messrs Chetty & Patel [2000] EWCA Civ 267. Appeal allowed in part.
• Leicester County Court: His Honour Judge O’Rorke permitted amendment of the particulars of claim but refused permission for the proposed valuation and handwriting expert evidence.