EXPERT WATCH 10: CLAIMANT UNSUCCESSFUL ON APPEAL IN ATTEMPTING TO OVERTURN THE TRIAL JUDGE’S PREFERENCE FOR THE DEFENDANT’S EXPERTS: “THE IRREDUCIBLE FACT IS IS THAT THE JUDGE ACCEPTED THE EXPERT EVIDENCE OF THE RESPONDENT’S KEY WITNESS AND PREFERRED TO OVER THE EVIDENCE OF THE APPELLANT’S KEY EXPERT WITNESS”
There are relatively few cases where a party appeals on the basis that trial judge was wrong to accept the evidence of one party’s expert witness in preference to the other. There are even fewer cases where such an appeal succeeds. Here we have a case where the appellate court considered in detail the claimant’s/appellant’s arguments about the trial judge findings on experts being wrong. The appellant’s arguments were not successful.
(This, apparently, is what cyclospora looks like. It is difficult to find and identify, as this judgment shows…)
“ The fact that there were points that could be made in favour of the conclusion that the Appellant had ingested cyclospora does not mean that the judge reached a conclusion that no reasonable judge could come to. It is almost always the case in a trial that there will be evidence pointing either way.”
KEY PRACTICE POINTS
This case shows the difficulty of appealing a trial judge’s view as to which expert should be preferred. The appellant faces an uphill struggle. The trial judge also rejected an argument that, in essence, liability should be established because the claimant had become ill. There is much to consider here, particularly for those involved in holiday illness litigation.
THE CASE
Rawson v TUI UK Ltd [2025] EWHC 2093 (KB) Mr Justice Cavangh
THE FACTS
The claimant suffered illness when on holiday. She brought an action for damages for personal injury alleging that she had suffered from food or drink contaminated with cyclospora. At trial the judge found that the claimant was an honest witness. However he preferred the defendant’s expert evidence on issues of liability and causation. The claimant appealed.
WHAT HAPPENED IN A NUTSHELL
The claimant’s case failed at trial. The trial judge preferred the evidence of the defendant’s expert that cyclospora was not, in fact, present. The claimant’s appeal against this finding was rejected.
THE ISSUE ON APPEAL
The central issue on appeal was whether the trial judge was wrong to accept the evidence of the defendant’s expert that cyclospora was not in fact present in the claimant’s stool and that an early laboratory finding that it was present was wrong. The stool was later tested at a specialist centre where cyclospora was not found.
“11. This left the third issue, which is the central one for the purposes of this appeal. This is what it was that caused the Appellant’s symptoms. The Appellant’s primary case was that the Appellant suffered food poisoning that was caused by cyclospora. Cyclospora is sometimes found in Mexico, and is transmitted via food and drink. On behalf of the Appellant, Mr Pennock stressed that the hotel was an all-inclusive hotel, and the Appellant had not eaten or drunk anything outside the hotel between her arrival in Mexico and falling ill, and so submitted that the only possible conclusion open to the court was that the food poisoning was caused by cyclospora pathogens in food or drink consumed at the hotel. He further submitted that, in any event, the Appellant did not have to identify the actual pathogen that caused her food poisoning, it being sufficient that her symptoms commenced on holiday. This was because she did not consume any food or drink, before her symptoms commenced, other than that provided by the hotel. Therefore, whatever the pathogens concerned, the illness must have come from food or drink that was consumed in the hotel.
12. This central issue can be subdivided into two subsidiary issues:
(1) Has the Appellant proved on the balance of probabilities that the pathogen that caused her illness was cyclospora?; and
(2) Has the Appellant proved on the balance of probabilities that her illness was caused by a pathogen in the food or drink that she consumed at the hotel, whether or not it was cyclospora.
13. Issue (1) was a key issue. Cyclospora is a pathogen that is found in some locations in Mexico but is rarely, if ever, found in the UK. Therefore, if the court was satisfied that the pathogen that caused the Appellant’s illness was cyclospora, that would put paid to the Respondent’s contention that the Appellant was suffering from the illness before she left the UK. More significantly still, cyclospora is a food-borne pathogen. Mr Saxby, counsel for the Respondent, accepted in argument before me that if the judge had found that the pathogen which had caused the Appellant’s illness was cyclospora, then it would have been highly likely that the judge would have gone on to find, on the balance of probabilities, that the cyclospora which infected the Appellant had been contained in food that she consumed at the hotel, and so it was highly likely that the judge would have found in the Appellant’s favour. It would still have been open for the Respondent to argue, notwithstanding a finding that the pathogen that caused the illness was cyclospora, that the Appellant had not ingested the cyclospora in food at the hotel in Neuva Vallarta, but the forensic reality was that the judge would find that she had done so.
14. As for (2), as I have said, the Appellant’s case did not depend entirely upon a finding that she had been infected by cyclospora. She contended that, if not cyclospora, some other pathogen or pathogens in the hotel food and drink must have been the cause of her illness. Therefore, a finding that the Appellant had been unable to prove that the pathogen in question was cyclospora was not fatal to her claim. However, as I have said, a finding that the Appellant had been infected by cyclospora, rather than another pathogen, would greatly have assisted her case. Regardless of whether the cause was cyclospora or another pathogen, however, Mr Pennock submitted to the judge that the possibility that the Appellant had been infected with food poisoning or some other illness before she departed for Mexico could be, and in the event was, excluded. Mr Pennock pointed to the fact that the Appellant had been staying in an all-inclusive hotel and so had been living in what is sometimes described as a “closed system”. There was, he submitted, in reality no other candidate for the cause of the Appellant’s illness, apart from the food and drink supplied by the hotel. The Appellant also relied on evidence that was said to show that the hotel’s food hygiene standards were sub-optimal, and that there had been recorded outbreaks of food poisoning at the hotel in other months in 2016. It was true that there had been no other recorded episodes of food poisoning at the hotel in July 2016, but there were records of undiagnosed illness (diarrhoea and vomiting) at the hotel in other months in Summer 2016, and Mr Pennock submitted that there was evidence that the hotel’s record-keeping was incomplete.
15. At trial, the court heard from four expert witnesses. These were two gastroenterologists, Dr Bowling for the Appellant, and Professor Bjarnason for the Respondent, and two microbiologists, Professor Threlfall for the Appellant, and Dr Gant, for the Respondent.
16. I will deal in detail with the grounds of appeal advanced by Mr Pennock later in this judgment. In short, however, he submitted that the judgment should be set aside because, in a number of respects, the judge misstated, misunderstood, or misremembered the evidence, he failed to give adequate weight to key parts of the evidence, and/or he failed deal with relevant matters or to give adequate reasons for the conclusions which he reached. In particular, he submitted that the judge had been wrong to find that:
(1) The fact that the national reference laboratory report had not found a cyclospora oocyte in its test meant that he could not be satisfied, to the civil standard, that the Appellant had ingested cyclospora. The judge found, in effect, that the regional laboratory had been “mistaken” in finding cyclospora oocytes in the Appellant’s stool sample. As a result of this conclusion, the judge proceeded on the basis that the pathogen ingested by the Appellant that caused her illness was not cyclospora, and it must have been another, unidentified, pathogen (“the cyclospora issue”); and
(2) The Appellant had not proved that the pathogen she undoubtedly ingested whilst at the hotel was from the hotel’s food or drink (the Appellant not having consumed food or drink from anywhere else but the hotel). There may have been another cause, for example she could have touched a surface contaminated by an unidentified pathogen and then put her hand in her mouth (“the causation issue”).
17. As I have indicated, if the judge had found in the Appellant’s favour on the cyclospora issue, then in all likelihood the judge would also have found in the Appellant’s favour on the causation issue and so her claim would have succeeded.
18. There is no suggestion that the judge misdirected himself in law, or that he misdirected himself about the burden and standard of proof.
19. On behalf of the Respondent, in excellent submissions, Mr Saxby submitted that there was ample evidence to support the judge’s conclusion on the cyclospora issue, and, in particular, to support the judge’s reliance on Dr Gant’s view that the result of the national reference laboratory was the one to be relied upon. Mr Saxby submitted that Mr Pennock had misunderstood the answers given by Dr Gant at the end of his cross-examination and during his re-examination. Those answers did not amount to a concession that, on the balance of probabilities, the cause of the Appellant’s illness was cyclospora. As a result of his misunderstanding, Mr Saxby said, Mr Pennock had refrained from cross-examining Dr Gant on the causation issue if another pathogen was the cause of the illness. The judge was entitled to accept Dr Gant’s views on this issue, and, Mr Saxby submitted, Mr Pennock is taking points on appeal which he did not deal with by way of cross-examination of Dr Gant. Mr Saxby submitted that Mr Pennock should not be permitted to do so, because a trial is not a dress rehearsal. Mr Saxby further submitted that the judge had given, at the very least, adequate reasons for his decisions on the cyclospora and causation issues.”
APPEALS ON EXPERT EVIDENCE
The judge considered the criteria for appeals on issues of fact and then went on to consider the guidance in relation to appeals in relation to findings on expert evidence.
“(2) Appeals on matters expert evidence
“11 A first instance judge’s assessment of, or evaluations based upon, expert evidence adduced at trial must be approached by an appellate court with similar caution. Whilst it has been said that a reconsideration of an expert’s opinion may be slightly easier than a finding of fact, because the underlying report will be in writing (see Thomson v Christie Manson & Woods Ltd [2005] EWCA Civ 555; [2005] PNLR 38), the same case also provides a salutary warning that, since the evaluation of expert evidence is likely to be bound up with a wider evaluation of matters of fact, an appellate court will still be very slow to intervene. At para 141 of his judgement in Thomson’s case, May LJ said:
“But, even accepting that individual points such as these are amenable to judicial appellate evaluation whatever the expert opinion, no appellate court should cherry pick a few such points so as to disagree with a composite first instance decision which, in the nature of a jig-saw, depended on the interlocking of a very large number of individual pieces, each the subject of oral expert evidence which the appellate court has not heard.”
“It is a commonplace that this court will only rarely disturb a judge’s finding of fact reached after hearing oral evidence whose credibility is in issue. It may sometimes be somewhat less difficult to depart from an evaluative judgment of expert evidence, if the evidence is mainly in writing and its evaluation an intellectual process largely unaffected by personal credibility. But that is not this case…..[The judge’s] conclusions are in each instance supported by credible evidence. The existence of other evidence does not render these judgments wrong nor does it persuade me that he should have reached an opposite conclusion. ….Restating evidence and submissions which the judge rejected does not persuade me that the judge was wrong, when the judge’s conclusions were supported, as they were, by the opinions of Christie’s experts.”
24. Wheeldon, and the authorities referred to therein, make clear that an appellant has a high hurdle if he or she wishes to persuade an appellate judge that the trial judge was not entitled to come to the conclusion that he or she came to on matters of fact and expert evidence, including evaluations and conclusions based on that evidence.
53. The judge preferred Dr Bowling’s evidence to that of Professor Bjarnason, because the judge took the view that Professor Bjarnason had a tendency to express views on matters that were outside his area of expertise. The judge accepted Dr Bowling’s view that, if the Appellant had a cyclospora infection, she was and remained symptomatic. However, the gastroenterologists deferred to the microbiologists on the cyclospora issue, and so the views of the gastroenterologists did not determine the cyclospora issue (or the causation issue).
54. The judge preferred the evidence of Dr Gant to that of Professor Threlfall. He observed that Professor Threlfall accepted that Dr Gant has greater experience for testing for cyclospora oocytes. Dr Gant’s laboratory (the national reference laboratory) has the expertise and Professor Threlfall’s does not. Dr Gant’s evidence on the testing process was more cogent. He was right, and Professor Threlfall, was wrong, when Dr Gant said that there was no antibody for the oocytes and that they fluoresced naturally, and Professor Threlfall said that there was an antibody, and also when Dr Grant said that the oocytes did not deteriorate rapidly over time, and Professor Threlfall said that they did. Professor Threlfall’s suggested explanation for the different results, that the oocytes had disappeared from the stool sample between tests, was therefore not accepted. Both microbiology experts made clear that the identification of cyclospora oocytes was not easy, and they could readily be confused with other pathogens, such as yeast. The purpose of the national reference laboratory was to check that the initial findings of the regional laboratory were correct, and they had done their job and had concluded that they were not correct.
55. The judge said that he would have required extremely cogent evidence to persuade him that the national reference laboratory had got it wrong, and there was no such evidence.
56. For these reasons, the judge found on the balance on probabilities that the Appellant did not have cyclospora in her stool sample and so there was no direct evidence of the presence of cyclospora. The judge concluded that the Appellant’s symptoms were caused by another pathogen.
THE APPEAL JUDGE’S CONCLUSIONS IN RELATION TO THE APPEAL IN RELATION TO THE TRIAL JUDGE’S CONCLUSIONS ON THE EXPERT EVIDENCE
The judge found for the defendant/respondent. The claimant had not established that the trial judge had erred. The trial was entitled to accept the evidence of the defendant’s expert on the key point as to whether cyclospora was in fact present.
“90. I have carefully considered all of the grounds and submissions that have been advanced on behalf of the Appellant by Mr Pennock. In my judgment, there were ample grounds for the judge’s conclusion that the Appellant’s illness was not caused by the cyclospora pathogen. There was evidence to support the findings made and the conclusions reached by the judge. The judge did not misunderstand the evidence, and the conclusions on the facts and the expert evidence were ones that a reasonable judge could reach. Furthermore, the judge gave more than adequate reasons for this conclusion.
91. There was no dispute that the regional laboratory recorded that cyclospora oocytes had been found in the Appellant’s stool sample, and the national reference laboratory did not find any cyclospora oocytes in the sample.
92. There was a dispute in the expert evidence about the conclusions to be drawn from the analyses of the Appellant’s stool samples that were carried out by the regional and the national reference laboratories, and the other evidence. Standing back, and looking at the matter in the round, it came down to which of the microbiology witnesses’ evidence the judge preferred.
93. The judge was plainly right to focus on the expert evidence of the microbiologists. The gastroenterologist who was instructed on behalf of the Appellant, Dr Bowling, accepted that he had to defer to the expert microbiologists on causation. Causation, for this purpose, included both the identification of the particular pathogen that had caused the illness, and then working out the source of the pathogen. The judge was fully entitled, and, indeed, undoubtedly right, to conclude from this that Dr Bowling could not help on the cyclospora or conclusion issues. The gastroenterologist who was instructed on behalf of the Respondent, Professor Bjarnason, also deferred to the microbiologists on issues of causation. To the extent that he strayed beyond the limits of his specialist expertise, and again quite rightly, the judge discounted his evidence.
94. This meant that the judge was faced with conflicting evidence from the microbiologists on the cyclospora issue. The Appellant’s expert, Professor Threlfall, held the view that, in light of the result of the tests at the regional laboratory, and notwithstanding the outcome of the tests at the national reference laboratory, it was clear that the Appellant had ingested cyclospora. Conversely, the Respondent’s expert, Dr Gant, held the opposite view: he considered that the court should rely upon the result of the test at the national reference laboratory, even though it contradicted the result at the regional laboratory. Both of the microbiology experts gave reasons for the view in reports, Part 35 Answers, and a joint statement, and their views were tested by cross-examination. The judge decided that he preferred Dr Gant’s view. He gave reasons for this decision, each of which was supported by the evidence:
95. Dr Gant had greater experience in testing for cyclospora oocytes. This was not in dispute. Professor Threlfall had accepted this. Dr Gant was Director at the National Hospital for Tropical Diseases. The national reference laboratory was based there and Dr Gant had ultimate responsibility for it;
96. The national reference laboratory had greater experience than the regional laboratories. This was borne out by the evidence. Cyclospora is not endemic or common in the UK and so regional laboratories are not used to testing for it. The national laboratory, on the other hand, is a national reference laboratory for a reason, because those who work there have the greatest experience in testing for what in UK terms are esoteric pathogens. This is why the purpose of the national reference laboratory was to check the initial findings of the regional laboratory. Dr Gant had said that laboratory technicians in the UK generally are not highly experienced whereas staff at the national reference laboratory have specific experience and training in identifying the organism. Professor Threlfall had accepted in evidence that the national reference laboratory testing was the” gold standard”. He also accepted that testing for cyclospora was “notoriously difficult”;
97. Dr Gant’s evidence on the testing process was more cogent that Professor Threlfall’s. Again, this was a conclusion that the judge could come to on the evidence. The judge accepted, as he was entitled to, Dr Gant’s evidence that there was no antibody for the oocyte, over Professor Threlfall’s evidence that there was such an antibody;
98. Professor Threlfall’s suggested explanation for why the oocytes had been found in the regional laboratory test, but not, a week or so later, in the national reference laboratory test, was therefore rejected. Professor Threlfall had said that the antibody deteriorated or degraded rapidly over time and so might have disappeared in the week or so between the first test and the second. Dr Gant said that they did not. Dr Gant said that “oocytes will remain detectable in a stool sample for extended periods of time, far exceeding the time elapsed in confirmatory testing by the reference laboratory.” When he was pressed on this issue in cross-examination, Professor Threlfall admitted that he could not point to any scientific papers to back up his assertion; and
99. In light of the above, on the balance of probabilities the positive result at the regional laboratory was a false positive.
100. The fact that there were points that could be made in favour of the conclusion that the Appellant had ingested cyclospora does not mean that the judge reached a conclusion that no reasonable judge could come to. It is almost always the case in a trial that there will be evidence pointing either way.
THE APPEAL JUDGE’S CONCLUSION: APPEAL REFUSED
140. I have dealt with the issues that have been raised in this appeal in considerable detail. I have, I believe, dealt with every one of the grounds raised by Mr Pennock on behalf of the Appellant. They do not persuade me, singly or together, that the appeal should be allowed. But I remind myself, in any event, that the judge had the benefit of hearing all of the evidence, which I did not. As Lewison LJ said in the Fage case, cited in Wheeldon, all an appellate judge does is a form of island hopping. Even if one or two of the points raised by Mr Pennock had some force, I would have been reluctant to consider allowing the appeal. This was a careful and impressive judgment which addressed all of the main issues in the case. The judge was better placed than me to consider all of the evidence. The irreducible fact is that the judge accepted the expert evidence of the Respondent’s key witness and preferred it over the evidence of the Appellant’s key expert witness. I also bear in mind what was said in Fage to the effect that a trial is not a dress rehearsal. The purpose of an appeal is not to allow the losing party an opportunity to rehearse the same arguments before a different judge in the hope that the different judge will reach a different conclusion.”
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