ES v Chesterfield and North Derbyshire Royal Hospital NHS Trust

Expert evidence must be restricted to what is reasonably required to resolve the proceedings. Although the vast majority of cases should involve no more than one expert in each speciality, that approach is not inflexible. The court must decide whether additional evidence will assist it to do justice, and to be seen to do justice, on the particular facts.

Relevant considerations include equality of footing, the claim’s value and importance, the complexity of the issues, proportionality and the parties’ financial positions. In professional negligence litigation, clinicians called as factual witnesses may inevitably give evidence informed by their expertise. Their presence can therefore create an exceptional imbalance which justifies permitting an opposing party to call a second independent expert.

The claimant, a child with cerebral palsy caused by severe hypoxia immediately before her birth, brought a substantial clinical negligence claim against the hospital trust. The principal allegations concerned clinical decisions made by an obstetric registrar and a consultant during an unsuccessful attempted instrumental delivery.

At a case management conference, Master Ungley limited each side to one obstetric expert. He rejected the claimant’s contention that equality required her to call two experts, notwithstanding that the defendant would also call the registrar and consultant as factual witnesses. The master granted permission to appeal because the issue raised a point of practice and procedure of significant importance.

The central question was whether, under Rules 1.1, 35.1 and 35.4 of the Civil Procedure Rules, a second obstetric expert was reasonably required to achieve justice on the exceptional facts of the case.

1. Appeal allowed unanimously. Brooke LJ, with whom Holman J and Kennedy LJ agreed, held that the master had been clearly wrong to isolate the clinicians’ factual evidence from their professional experience when assessing equality between the parties. The order was varied to permit the claimant to call two obstetric experts.

2. Rule 35.1 of the Civil Procedure Rules restricts expert evidence to that reasonably required to resolve the particular proceedings. The court should ordinarily permit no more than one expert in a speciality. That is not a mechanistic or predetermined rule. The assessment is fact-sensitive and must reflect the overriding objective in Rule 1.1.

3. The principal considerations were equality of footing, proportionality to the value and importance of the claim, the complexity of the issues and the parties’ financial positions. The underlying question was whether the additional evidence would assist the court to do justice, and to be seen to do justice, between the parties.

4. In a professional negligence action governed by the Bolam test, clinicians called as factual witnesses may properly explain and justify their conduct by reference to their training and experience. Although they remain fact witnesses, the court cannot ignore the expert character of that evidence. Here, the defendant would effectively have the benefit of evidence from two senior clinicians and an independent obstetric expert, while the claimant would otherwise have had only one obstetric voice.

5. The exceptional imbalance, the substantial value and importance of the claim, and the modest additional cost and trial time made the second expert proportionate and reasonably necessary. The judgment gave no general encouragement to employ two experts in one discipline. Whether the defendant should later be allowed a second independent expert was left for future case management after exchange of the expert evidence.

The respondent was ordered to pay the claimant’s publicly funded costs of the appeal, subject to assessment. Permission to appeal to the House of Lords was refused.

1. Court of Appeal (Civil Division): The claimant’s appeal was allowed unanimously. The case-management order was varied to permit her to call two experts in obstetrics. Permission to appeal to the House of Lords was refused.
2. High Court, Queen’s Bench Division: At a case management conference, Master Ungley directed that each side’s obstetric evidence be limited to one expert. He refused the claimant’s application to call a second expert but granted permission to appeal.