Jimmy Barber of our Personal Injury team summarises the Court of Appeal’s decision in the case of Griffiths v TUI UK Ltd [2021] EWCA Civ 1442, which was handed down on 7th October 2021.

This case specifically concerns the correct judicial approach to ‘uncontroverted’ expert evidence in the context of a holiday sickness claim, but dicta both from the majority (Asplin LJ and Nugee LJ) and the dissenting judgment of Bean LJ discuss some issues of broader relevance, in particular regarding the procedural fairness of refraining from cross-examining an expert and waiting instead to criticise that expert’s opinion in closing submissions.


The Claimant and his wife bought from the Defendant tour operator an all-inclusive two-week holiday in August 2014 at the Aqua Fantasy Aqua Park Hotel in Izmir, Turkey. On the third day of the holiday, the Claimant fell ill with stomach cramps and diarrhoea. He remained ill throughout the holiday and ultimately required hospital admission with acute gastroenteritis. A stool sample showed multiple pathogens, both parasitic and viral. As a result of the illness, he lost weight, his appetite was affected for a number of months, and he still had residual symptoms at trial in September 2019.

At first instance

Proceedings were issued in the County Court. The Claimant relied on expert reports from Dr Thomas, a gastroenterologist, on condition and prognosis and Professor Pennington, a microbiologist, on causation. The Defendant was granted permission to obtain its own expert evidence in both of these disciplines, but chose not to serve a microbiology report and was refused relief from sanction in respect of the late service of a gastroenterologist report.

At trial, HHJ Truman heard oral evidence only from the Claimant and his wife. There were written statements from a medical doctor at the hotel and from the head of guest relations at the hotel. Professor Pennington confirmed he had considered these statements, along with the Defendant’s disclosed documents, in reaching his opinion on causation.

The Defendant criticized a number of aspects of Professor Pennington in its closing submissions. HHJ Truman held:

It is trite law that the burden of proof is on the claimant. It is open to a defendant to sit back and do nothing save make submissions, and if the evidence is not sufficient to satisfy a court on the balance of probabilities, a claimant will not succeed. … I accept counsel for the defendant’s submissions that a number of the assertions made are bare ipse dixit. There is sometimes a huge gap in reasoning between undoubted factual matters (such as incubation periods) and the conclusion that the hotel was at fault. The court is not a rubber stamp to just accept what someone has said. When causation is clearly in issue, I do consider it incumbent on the medical experts to provide some reasoning for their conclusions.”

The judge adopted a number of criticisms of Professor Pennington’s opinion advanced by the Defendant, and went on to dismiss the claim on the basis that the Claimant had not proved his case on causation.

Appeal to High Court

The Claimant appealed to the High Court with the permission of Pepperall J, on the grounds that the court had erred in rejecting the ‘uncontroverted’ expert evidence on causation from Professor Pennington.

Martin Spencer J observed (at para. 10) that while the report of Professor Pennington was undoubtedly short and even minimalist:

on the issue of causation, the only expert evidence before the learned judge was the report and the part 35 answers of Professor Pennington. These were uncontroverted in the sense that the Defendant did not call any evidence to challenge or undermine the factual basis for Professor Pennington’s report, for example by calling witnesses of fact or putting in documentary evidence; nor was there any successful attempt by the Defendant to undermine the factual basis for the report through cross-examination of the Claimant and his wife, nor by cross-examination of Professor Pennington. In this sense, and unusually, the evidence of Professor Pennington was truly “uncontroverted”.”

He went on to hold (at para. 33):

In the absence of direct authority on the issue, I take the view that a court would always be entitled to reject a report, even where uncontroverted, which was, literally, a bare ipse dixit, for example if Professor Pennington had produced a one sentence report which simply stated: ‘In my opinion, on the balance of probabilities Peter Griffiths acquired his gastric illnesses following the consumption of contaminated food or fluid from the hotel.’ … However, what the court is not entitled to do, where an expert report is uncontroverted, is subject the report to the same kind of analysis and critique as if it was evaluating a controverted or contested report, where it had to decide the weight of the report in order to decide whether it was to be preferred to other, controverting evidence such as an expert on the other side or competing factual evidence. Once a report is truly uncontroverted, that role of the court falls away. All the court needs to do is decide whether the report fulfils certain minimum standards which any expert report must satisfy if it is to be accepted at all.”

The judge went on to hold that HHJ Truman was not entitled to reject the evidence of Professor Pennington for the reasons that she did. However strong were the criticisms of the report – and the court accepted that the criticisms were strong – they went to an issue with which the judge at first instance was not concerned, namely the weight to be ascribed to the report. The appeal was allowed and judgment was entered for the Claimant.

Second appeal

The Court of Appeal were split 2-1 in favour of allowing the appeal.

Majority view, Asplin LJ and Nugee LJ

The majority did not consider that the authorities, which included the Supreme Court’s decision in Kennedy v Cordia LLP [2016] 1 WLR 597, supported the bright line approach taken by the High Court in distinguishing between uncontroverted and controverted evidence (per Asplin LJ at para. 40).

At the end of the trial, the exercise of the normal judicial function was to apply the burden of proof and to find the facts having regard to all the evidence in the case, which may include both evidence of fact and evidence of opinion which may interrelate, as per Clarke LJ in Coopers Payne Ltd v Southampton Container Terminal Limited [2004] Lloyds Rep 331 (para. 48).

There was no strict rule that uncontroverted evidence must be accepted at face value, whatever it says, although if unchallenged expert evidence is to be rejected, then it must be rejected for a reason (para. 57).

The view of the majority was that there is nothing inherently unfair in seeking to challenge expert evidence in closing submissions, even if contrary evidence has not been adduced and the expert has not been cross-examined. As long as an expert’s veracity is not challenged, a party may reserve its criticisms of a report until closing submissions if it chooses to do so. A defendant is entitled to submit that the case or an essential aspect of it has not been proved to the requisite standard, and cannot be prevented from doing so because some of the evidence is contained in an uncontroverted report. As HHJ Truman had held at first instance, the court is not a rubber stamp (para. 65).

Asplin LJ went on to hold that, even though CPR PD 35 para. 3(2)(6)(b) states that an expert is only required to provide reasoning for his or her conclusion where there is a range of opinion, it is apparent from the dicta of Lords Hodge and Reed in Kennedy v Cordia that in most cases, some reasoning is necessary in order to support an expert’s conclusion; otherwise, it is all but worthless (para. 76).

The majority concluded that HHJ Truman had been entitled to conclude that Professor Pennington’s evidence – which ran only to four substantive paragraphs – was insufficient to satisfy the burden of proof (per Asplin LJ at para. 78 and per Nugee LJ at para. 84).

Dissenting judgment

Bean LJ’s dissenting judgment was predicated essentially on the grounds that it was unfair for defendants to make closing submissions inviting the court to reject an expert’s opinion without first having put those criticisms to the expert in cross-examination.

He agreed with the other judges that the High Court had been wrong to hold that a judge was effectively bound to accept the evidence of an expert if it is not controverted by other expert or factual evidence; but he considered that a judge is generally bound to accept the evidence of an expert if it is not controverted by other expert of factual evidence and the opposing party could have cross-examined the expert on the point but chose for tactical reasons not to do so (para. 94).

In his judgment, the principle that requires challenges to be put to witnesses, including experts, was not narrowly confined to the situation in which the veracity of the witness was in issue (para. 90). He did not accept that Kennedy v Cordia provided any support at all for the proposition that a defendant can seek to dismantle the reasoning of an expert for the first time in closing submissions without having applied to cross-examine the expert (para. 95).

The judge concluded by saying (at paras 98 and 99):

Mr Griffiths must be wondering what he did wrong. He instructed a leading firm of personal injury solicitors, who in turn instructed an eminent microbiologist whose integrity has not been questioned. Mr Griffiths and his wife gave evidence at the trial, were cross-examined, and were found by the judge to be entirely honest witnesses. The eminent expert gave his opinion that on the balance of probabilities Mr Griffiths’ illness was caused by the consumption of contaminated food or fluid supplied by the hotel. No contrary evidence was disclosed or called, and the expert was not cross-examined. Yet the Claimant lost his case.

Asplin LJ, with whom Nugee LJ agrees, says at [65] that ‘as long as the expert’s veracity is not challenged, a party may reserve its criticisms of a report until closing submissions if it chooses to do so’, and that she can see nothing which is inherently unfair in that procedure. With respect, I profoundly disagree. In my view Mr Griffiths did not have a fair trial of his claim. The courts should not allow litigation by ambush.


After the High Court handed down its judgment in August 2020, defendant tour operators issued a flurry of applications in holiday sickness cases on the fast-track in the County Court (in which permission is often granted only to the claimant to rely on expert evidence) requesting the attendance of claimant experts for cross-examination at trial.

The purpose of those applications was to seek to avoid being saddled with ‘uncontroverted’ expert evidence at trial which the court would be bound to accept. The outcome of this appeal ought to put those particular concerns to bed.

There are a couple of broader lessons which may be taken from this judgment.

First, it stands as a warning – if it was still needed – to claimants to ensure that any expert evidence they seek to rely upon should not only meet the basic requirements of Part 35 but must also be sufficiently well-reasoned to fend off the argument that the evidence does not satisfy the burden of proof.

An unusually short report like Professor Pennington’s may be the exception rather than the rule, but it is also not uncommon to see reports which may be many pages long but in which the opinion/analysis section is very brief. These types of reports ought to set off alarm bells too: if the report is light on reasoning, it is unlikely to hold much weight with the court.

Secondly, while this judgment makes clear that it is not impermissible to reserve any criticisms of an expert’s report to closing submissions without having adduced contrary evidence or having cross-examined the claimant’s expert, Asplin LJ nonetheless considered this a ‘high-risk’ strategy. Saying that something is not prohibited is of course not the same as wholeheartedly endorsing it.

Indeed, when a Court of Appeal judge has deprecated an approach – even if only in a dissenting judgment – it may be sensible for defendants wishing to go down this route to give pause and, at the very least, foreshadow any intended criticisms of the claimant’s expert in the defence. This may avoid allegations of conducting litigation by ambush.

Aside from the difference of opinion on the Court of Appeal bench regarding this issue of procedural fairness, however, Griffiths merely restates some fundamental and uncontroversial principles.

It is the reasoning which carries the weight in an expert’s evidence, not the conclusion. In most cases, a well-reasoned expert opinion which is uncontroverted by other evidence or cross-examination is unlikely to be rejected by the court; but, given that the trial judge’s function is to evaluate all the evidence in the case, the court is not ever bound by an expert’s conclusions, and remains the ultimate arbiter of the weight to attach to that opinion.

Judgment can be found here.

Jimmy is a specialist practitioner in the fields of clinical negligence, personal injury and industrial disease. He advises on and settles pleadings in a variety of consumer aviation and travel claims. These include carriage by air disputes involving Regulation (EC) No.261/2004 and the Montreal Convention, such as denied boarding, flight delays, lost baggage and passenger injury claims; personal injury claims involving the Package Tours Regulations; and advising on conflicts of laws and jurisdictional issues. Read more here.