High Court decisions on admissibility of opinion evidence

In two recent decisions, the High Court has considered the circumstances in which opinion evidence contained in third party reports or articles is admissible in civil proceedings. In Rogers v Hoyle [2013] EWHC 1409 (QB), the court had to consider whether a report produced by the Air Accident Investigation Branch of the Department for Transport (the "AAIB") was admissible in a negligence claim against the pilot of the airplane involved in the crash. In Interflora Inc v Marks and Spencer PLC [2013] EWHC 936 (Ch), the question was whether academic journal articles relating to internet literacy were admissible in a trade mark infringement claim.

In Rogers, the court considered whether the AAIB report had to be excluded as a result of the substantial body of authority demonstrating that findings of tribunals and inquiries are not generally admissible in subsequent proceedings - the so-called rule in Hollington v Hewthorn [1943] KB 587. The judge distinguished this line of authority on the basis that it applies only to judicial findings (which must be based solely on the evidence adduced by the parties) rather than those of an expert investigator (which are based on the expert's own technical knowledge and experience). The AAIB report fell into the latter category and therefore did not have to be excluded under that rule.

In both cases, the court held that although the evidence in question was "expert evidence" in a general sense, it did not fall within Part 35 of the Civil Procedure Rules and therefore the court's permission was not required to adduce it. Each judge concluded that Part 35 controls only the giving of evidence by an "expert" as defined in that part, i.e. "a person who has been instructed to give or prepare expert evidence for the purposes of proceedings".

The key points arising from these first instance decisions are:

• Judicial findings, based solely on the evidence adduced by the parties, are not admissible in subsequent civil proceedings (subject to a statutory exception for evidence of criminal convictions). This rule does not however apply to the findings of an expert who is entitled to draw on his or her own knowledge and experience in reaching conclusions.
• The court's permission is not required to adduce pre-existing evidence containing expert opinion, such as a third party report or article. Permission is only required where the expert has been instructed for the purposes of the proceedings.
• The court does however have a discretion to exclude such evidence, and may do so for example if the evidence is of a sort that the court would have difficulty understanding and evaluating without an expert's assistance.

Legal background

It is a long-standing rule of evidence that a person's opinion is not generally admissible to prove the truth of the opinion held. This is often said to be because opinion evidence is irrelevant; it is the judge's role to evaluate the evidence before the court, and he or she must not defer to the opinion of anyone else.

There are exceptions to this principle, however, where the opinion is held by a person who is better placed to form that opinion than the judge - most obviously an expert opinion on a subject requiring specialist knowledge, or where a person has observed the relevant events first-hand.

There is also a long-standing rule that findings of tribunals and inquiries are not admissible in subsequent proceedings (unless they give rise to an issue estoppel). The leading authority is Hollington v Hewthorn [1943] 1 KB 587, in which the Court of Appeal ruled that a defendant's conviction for careless driving in a collision was inadmissible in a negligence claim brought against him by those injured in the collision. The Court of Appeal described the opinion of the criminal court as "irrelevant" in the trial of the issue in the civil court.

The actual decision in Hollington v Hewthorn - that a criminal conviction is not admissible in civil proceedings - has been reversed by statute (section 11 of the Civil Evidence Act 1968). But that does not affect the application of the rule to findings made in earlier civil proceedings. The rule was referred to by the House of Lords in Three Rivers District Council v Bank of England (No 3) [2003] AC 1, in agreeing that the report of the Bingham inquiry into the collapse of BCCI would not be admissible at the trial of the action.

Rogers v Hoyle

As noted above, the question in Rogers was whether an AAIB report of its investigation into an air accident was admissible in a negligence claim against the airplane pilot. The claimants had given notice of their intention to rely on the report as hearsay evidence at trial, as required by the Civil Evidence Act 1995, and the defendant contested its admissibility on the basis that it consisted of inadmissible opinion evidence.

The judge (Leggatt J) held that the report was admissible. It contained, the judge said, a wealth of relevant and potentially important evidence which bore directly on the issues in the action. Although much of the evidence could, in principle, be obtained from other sources, the fact that the AAIB investigation was carried out immediately after the accident when the evidence was fresh gave it an advantage that no subsequent investigation could replicate. The judge commented: "If any non-lawyer was told that the law does not permit a court to have regard to the AAIB report when deciding how the accident was caused, I am sure that he or she would express astonishment at the suggestion. Unless the court is prevented from doing so, it would be foolish and blinkered to ignore such a valuable resource." The judge also referred to a number of cases in which AAIB reports had been relied on without any challenge.

The judge agreed that the report contained opinion evidence. These were not, however, opinions of a lay person but rather of AAIB inspectors with particular knowledge and experience in the relevant area. They were not therefore inadmissible on that basis.

Nor were they inadmissible under the rule in Hollington v Hewthorn.  The judge reviewed the authorities in which that rule has been applied, noting that although the rule has been much criticised it has never been over-ruled and therefore remains good law (except in so far as reversed by statute). He explored the justification for the rule, finding that it lies in the requirements for a fair trial: it is the judge's  responsibility to make an independent assessment of the evidence and therefore weight ought not to be attached to conclusions reached by another judge - not least because in civil proceedings it is up to the parties what material they place before the court, and a party to a subsequent action out not to be prejudiced by the way a party to the first action conducted its case.

Leggatt J distinguished judicial findings from expert opinions, finding that the rule applies only to the former. Judicial findings are those based solely on the evidence before the court, where the judge is neither expected nor permitted to use technical knowledge of the subject matter of the case. In contrast, an expert's conclusions are based at least in part on the expert's own knowledge and experience. The AAIB report was a report of an expert investigator, and so the rule in Hollington v Hewthorn did not apply.

The judge also found that the claimant did not require permission to adduce the report, as it was not expert evidence for the purposes of CPR Part 35. Although the court had a discretion to exclude it, under the court's inherent jurisdiction and under CPR Part 32 which gives the court express powers to exclude evidence that would otherwise be admissible, it was not appropriate to do so. The question of what weight to give the contents of the report (for example because it is an anonymised document with opinions and findings that are not attributed to any individual) was a matter for the trial judge.

Interflora Inc v Marks and Spencer PLC

In Interflora, the question was whether academic articles which the claimants sought to adduce as hearsay evidence were admissible. The defendant objected primarily on the basis that they contained expert evidence, so were admissible under CPR Part 35 (i.e. with the court's permission) or not at all. The judge (Arnold J) concluded that the articles did not constitute expert evidence for the purposes of CPR Part 35, which applied only to the evidence of an expert instructed for the purposes of proceedings. The court's permission was therefore not required to adduce the evidence.

The court also declined to exercise its discretion to exclude the evidence. The court agreed with the defendant that the court should be astute to attempts to "turn the court itself into its own expert", saying he felt discomfort at the proposition that scientific literature can be put before courts without the benefit of an expert's report to put the literature into context and an expert to be cross-examined. However, the crucial question was whether the court could understand and evaluate the material in question without the assistance of an expert. Whatever might be the position in other cases, here the judge had seen nothing which led him to believe he would have difficulties.

Note: te: The decision in Rogers v Hoyle has been upheld by the Court of Appeal: see [2014] EWCA Civ 257.