Can a party rely on an external report that contains opinion evidence? The Court of Appeal considered this question in a case reported today Hoyle -v- Rogers[2014] EWCA Civ 257.  Important distinctions have to be drawn between admissibility and weight of evidence. 

The facts

The claimants were the executors of a man who had died when an aircraft piloted by the defendant had crashed. They alleged negligence on the part of the defendant and sought to rely on the Air Accident Investigation Branch (AAIB) report. The defendant subsequently sought a declaration that the AAIB report was inadmissible opinion evidence. Julia Mary Rodgers and Jade Rodgers v Scott Hoyle [2013] EWCH 1409

The findings at first instance: the report was admissible

It was held that the AAIB report did contain statements of both fact and opinion. However it was still admissible as evidence.

Court of Appeal judgment: judge’s decision upheld

The Court of Appeal upheld the decision of the judge at first instance.  The AAIB report was admissible.  However the weight it was given was a matter for the judge.


The nature of the Report

  1. The Report is a mixture of statements of fact and statements of opinion. In paragraphs 30-42 of his judgment the judge carefully analysed what was factual evidence and what was opinion in terms which I do not intend to rehearse. Some of the statements of fact are observations made by the inspectors themselves e.g. of the location of the wreckage or the nature and extent of the damage. Some are reports of what the pilot told the inspectors. In this respect significance is also sought to be attached to the fact that, according to the Report, the pilot, when asked what the recovery aspects from a spin should be, failed to mention some of what the Report describes as the “crucial inputs“. Some statements consist of what other unidentified eye witnesses (one a retired professional pilot) said they saw.
  1. The opinion evidence includes (i) the finding of an unidentified expert in aviation pathology at the post mortem of the deceased passenger; (ii) an analysis of recorded meteorological data carried out by the Met Office in order to obtain an estimate of wind and temperature at the scene; (iii) an analysis of data extracted from the flight track logs recorded by the Global Positioning System on board, which must have been done by someone with relevant expertise, as a result of which the tracks and altitude of the plane for the two flights had been plotted; and (iv) an opinion that the loop manoeuvre was carried out at too low a height to enable recovery from the subsequent spin and that the location and alignment of the rear fuselage and the ground marks made by the tail skid dragging to the left indicated that there was a rotation to the right when the aircraft struck the ground (when the pilot thought he was spinning to the left). As the judge rightly observed, the distinction between fact and opinion is not always clear; some statements in the Report might be regarded as mixed fact and opinion and in relation to technical matters there was no clear line between statements of fact and statements of opinion.
  1. The potential value of this material to anyone seeking to establish the cause of the accident (and any culpability therefore) is obvious. The inspectors are experienced and expert individuals fulfilling a public duty to investigate air accidents and incidents for the purposes of preventing further accidents or incidents in future. It is no part of their function to attribute blame or responsibility. There is, thus, no realistic possibility of their report being slanted so as to support or refute a claim that any individual or corporation is, or is not, at fault. Their investigation is carried out as soon as possible after the accident or incident. The investigators have the power, and, in practice, the ability to obtain the necessary information from a wide range of sources in order to establish, on the basis of information obtained soon after the relevant events, a composite picture of what happened and why. They need to do that in order to try and avoid it happening again. I agree with the judge when he said that a non-lawyer would be astonished that the report of the AAIB was not something to which a court could even have regard.


Expert evidence

  1. As Hollingthorn v Hewthorn recognises in terms, different considerations apply to scientific or expert witnesses. Insofar as an expert gives evidence of fact (e.g. where he found the wreckage to be) his evidence is as admissible as that of any other person. Where his evidence is evidence of opinion it is admissible because it is the product of a special expertise which the trial judge is unlikely to possess and which, even if he did, it is not his function to apply.
  1. As to the latter, it was suggested that the authors of the Report were not shown to have the necessary credentials to give evidence or, at least, that it was not possible to discern whether they did or not, especially since they are not named in the report. It might not, for instance, be the case that the investigator who was a pilot had any or any sufficient experience of planes of the vintage concerned, or of their use for aerobatic manoeuvres.
  1. I do not regard this objection as well founded. The identity of the principal investigators is known and their expertise must be a matter of public record or at least readily discoverable. The bar to be surmounted in order to count as an expert is not particularly high, the degree of expertise going largely to the weight to be given to the evidence rather than its admissibility. I have little difficulty in inferring that the authors of the Report may be treated, at this juncture, as being experts in their respective fields, as Tomlinson J, as he then was, did in Lambson Aviation v Embraer Empresa Brasileira de Aeronautica SA: see para 90 below.
  1. In Sunley v White (Surveyors & Estate Agents) Ltd [2003] EWCA Civ 240 this Court regarded as admissible a draft soil report issued by a company although the report was unsigned, provisional and did not carry the name or qualifications of the author. These were matters which Clarke LJ, with whom Longmore LJ agreed, treated as “essentially going to weight“. Part of the grounds of admitting the report was that it showed the type of survey report that the claimant would have received if the defendants had not been negligent – a question of fact. But the claimant was also permitted to resile from a concession previously made so as to allow them to rely upon the report for statements in it in relation to “contamination …and upon the figures“. This was a reference to the author’s opinion as to the extent of underground contamination at a petrol filling station and the cost of necessary remedial works.
  1. Nor do I regard it as any objection to the admission of the Report that it is the result of a team effort to which several experts contributed. In a field such as this that will inevitably be so: see R v Kershberg [1976] RTR 526 (not necessary for every stage of an analysis of urine to be done personally by the certifying analyst); R v Tate [1977] RTR 17. Nor does the fact that the senior (supervising) Inspector will have been in overall charge mean that he is to be regarded as no more than a non expert co-ordinator, since he will have at least one of the expert backgrounds of those preparing the report.
  1. One of the reasons for the rule in Hollington v Hewthorn, as explained by Lord Goddard, was that, if an earlier judgment was not to be conclusive, it:

ought not to be admitted as some evidence of a fact which must have been found owing mainly to the impossibility of determining what weight should be given to it without retrying the former case.

  1. In Calyon v Michailaidis the Privy Council held that a decision of a Greek Court was not admissible as evidence in proceedings in Gibraltar involving someone who had not been a party to the Greek proceedings. The Board cited Lord Goddard’s words above and observed at [27] that :

“..the essential reasoning is compelling: unless the second court goes into the facts for itself, it cannot actually tell what weight it should properly attach to the previous decision. Which means that the previous decision itself cannot be relied upon.

  1. The Committee concluded that, even if it was open to them to do so, they would not depart from the rule and admit the Greek judgment as evidence. The judgment did not indicate the substance of the evidence on which the court relied so that a judge of the Gibraltar Supreme Court would be in no position to determine what weight to give to the Greek judgment on the point.


  1. Mr Lawson submits that the Civil Evidence Acts and CPR 35 constitute a comprehensive code regulating the use of expert evidence. Under it a party is not entitled to call an expert or put in an expert report without the permission of the Court and, unless the Court otherwise directs, the report must comply with the requirement of the Practice Direction. The Report does not qualify under these rules.
  1. This submission is not well founded. Section 3 of the 1972 Act does not purport to be all embracing or to restrict or alter the position at common law. The expert with whom CPR 35 is concerned is a person “who has been instructed to give or prepare expert evidence for the purpose of proceedings“. The expert evidence referred to in CPR 35.1 and 35.5 and the expert’s report referred to in CPR 35.4 and CPR 35.10 are the evidence and report of such a person. The purpose of CPR 35 is to regulate the evidence of experts instructed by the parties, to ensure that they act as experts, and to regulate the use and content of their reports. The expert evidence in the Report does not fall within CPR 35. The AAIB was not instructed by, and is wholly independent of, any of the parties.
  1. CPR 35 is not a comprehensive and exclusive code regulating the admission of expert evidence. It regulates the use of a particular category of expert evidence. As the authors of Phipson observe, citing Lord Mansfield in Folkes v Chad (1782) 3 Doug 157:

even at common law the opinions of skilled witnesses were admissible wherever the subject is one upon which competency to form an opinion can only be acquired by special study“.

In 1782 there could be no question of hearsay expert opinion: but the law has moved on.

  1. The courts have in practice received expert evidence outside the confines of CPR 35. Thus in DN v London Borough of Greenwich [2004] EWCA Civ 1659 this Court held that the trial judge was wrong to decline to allow the defendants to a professional negligence claim to rely on the opinion evidence contained in the witness statement of a school educational psychologist who was said to have been negligent. That decision was applied by Jackson J, as he then was, in Multiplex Constructions (UK) Ltd v Cleveland Bridge Ltd [2008] EWHC 2220 (TCC) where he ruled that an engineer giving factual evidence could also proffer statements of opinion reasonably related to facts within his knowledge and relevant comments based on his own experience. If CPR 35 is to be treated as an exclusive code it would appear to render inadmissible as evidence, expert literature exhibited to the report of an expert called under CPR 35 – as Arnold J observed in Interflora Inc v Marks and Spencer Plc [2013] EWHC 936 (Ch).
  1. In Humber Oil Terminals Trustee Ltd v Associated British Ports [2012] EWHC 1336 (Ch) Sales J heard evidence from two experts called as such under CPR Part 35 as to the cost of building a replacement for an oil jetty. One of them – Mr Bartlett for the claimants (“HOTT”) – relied on certain estimates provided by a company called Foster Wheeler for a particular project. Foster Wheeler had relied on an indication of costs provided to them by a company called Nuttalls. The judge much preferred the evidence of the other expert. He also ruled that HOTT was not entitled to rely on the Foster Wheeler reports and the Nuttalls indication of cost of works as hearsay expert opinion. He considered that in substance HOTT was seeking to make use of that material in the same way as a party would seek to adduce and use an expert report. As a result it was subject to the CPR Part 35 regime when it sought to get the judge to accept and rely on the material as expert opinion rather than factual background. The position – he said – was “different from the kind of official reports referred to in Phipson, which (as there observed) “are not the reports of ‘experts within CPR Part 35”“.
  1. I would not regard the material in that case as wholly inadmissible. If it was it is difficult to see how Mr Bartlett could deploy it. It was, however, plainly not the evidence of an expert as defined in CPR Part 35 and was, therefore, subject to very limited weight – for the reasons set out in para 145 of Sales J’s judgment where he identified the weakness in Mr Bartlett’s evidence by reference to the weakness in the Nuttalls costs indication and the Foster Wheeler reports, including but not limited to the absence of any one from those companies being called to give evidence and subject to cross examination.
  1. Accordingly, in my judgment, the report was prima facie admissible and, since it did not fall within CPR 35, the claimant did not require the permission of the court to adduce it.


A key part of the judgment is the final paragraph.

“99.Nothing in this judgment should be taken to mean that anything in the Report is to be treated as conclusive or prima facie conclusive of anything; or as shifting the incidence of the burden of proof; or as precluding any party from challenging anything in it, or as restricting or limiting any other admissible evidence that any party may choose to call.”


  • The report is admissible but far from conclusive.
  • It does not shift the burden of proof.


The case, at first instance, was considered in an article I wrote on opinion evidence in witness statements for the Local Government Lawyer Do I want your opinion?