Evidence of Expert Opinion as Evidence of Fact

            In Kirkman v Euro Exide Corporation (CMP Batteries Ltd) [2007] EWCA Civ 66, it was claimed that a knee injury from an accident at work had resulted in the need for an operation which had been carried out and which had given rise to major complications. Each side was permitted to rely on the expert evidence of one Consultant Orthopaedic Surgeon. The Claimant’s expert was of the opinion that the need for the operation at that stage was necessitated by the accident, whereas the Defendant’s expert considered that the operation would have been necessary in any event because of pre-existing knee problems. The Claimant sought to rely on a statement from his treating surgeon to the effect that he would not have advised the Claimant to undergo the operation had it not been for the accident. The County Court judge held that the statement was expert evidence and refused to allow the Claimant to rely on it.

            The Court of Appeal allowed the Claimant’s appeal against this decision. Even though the treating surgeon was, in making his statement, relying on his expert knowledge, his statement was evidence of fact and not an evidence of expert opinion. The treating surgeon was simply speaking for himself and stating what advice he would have given had the accident not occurred; he was not saying that in his opinion his advice would have been correct, or that in his opinion most other competent surgeons would have given the same advice. He might be required to justify that opinion under cross-examination, which might draw him into the expression of expert opinion, and it would be a matter for the trial judge whether to permit such a development. But the County Court judge had erred in applying too rigidly the aspirational objective that the parties should operate under equality of arms when expert evidence is required.

            The important distinction between expert medical evidence and evidence as to what a treating doctor has, or would have, advised a patient who is a Claimant, the latter being evidence of fact, often arises in the context of a dispute between medical experts reporting for the parties as to the point in time at which a Claimant should reasonably have returned to work following an injury. In the unreported decision of Southgate v Port of London Authority (Court of Appeal judgment 14/2/75), there was such a conflict of opinion between the surgeons who gave evidence for each side and the trial judge preferred the evidence of the Defendant’s surgeon that the Plaintiff should have returned to work earlier than he had done, and held accordingly that he had failed to mitigate his loss. An appeal against this ruling was allowed on the basis that, as the Plaintiff had in fact been given certificates by his GP covering the whole of his period of absence and had effectively been advised by his GP not to return to work before he did, the Plaintiff had clearly been acting reasonably in relying on those certificates and that advice, regardless of the existence of a conflict of expert opinion between the surgeons instructed by the parties as to whether they would have agreed with this advice.

            Of course, as the Court made clear in that case, the same principle would not apply if it could be shown that the Plaintiff had done something to mislead his doctor into giving him such certificates and advice.

            And in Kirkham, the Court canvassed the ways in which the Defendant might be entitled to challenge the treating doctor’s evidence, “...at least theoretically, on the basis that it is not true, or more realistically on the basis that it is not reliable, but if it was sought to challenge his evidence on the basis that no other orthopaedic surgeon would have advised as he had done, his answer could quite properly be: “Well, that may be so, but right or wrong that’s what I would in fact have advised.””

                                                                                                IAN ASHFORD-THOM