Expert evidence:  a roundup of case law over the last 12 months

Our Annual Review for 2021 included an article by Huw Wilkins entitled “Expert Evidence: English courts send a message to experts”. As Ted Lowery explains, over the last 12 months the courts have continued to reinforce the message that CPR Part 35 and Practice Direction 35 must be satisfied and have imposed drastic consequences for non-compliance.


The judgments over the last 12 months can be broadly grouped under the following themes:

  • Permission for expert evidence.
  • Independence.
  • Unopposed expert evidence.
  • Expert (mis)behaviour.

Looking at these in turn.

Permission for expert evidence

CPR Part 35 states that expert evidence may only be adduced with the permission of the court. It should be borne in mind that the court’s permission is not automatic and that, when granted, the permission will often be restrictive, identifying the relevant disciplines and issues to be addressed by the experts. The court’s exercise of tighter control over expert evidence was one of the key objectives associated with the introduction of the Civil Procedure Rules in 1999, i.e., to reduce the proliferation of expert evidence in litigation (albeit primarily in the clinical negligence sector rather than in construction disputes).

A judgment from August 2022 illustrates that the court will not permit expert evidence that is considered superfluous, notwithstanding that the parties may have agreed to this. 

In Siemens Mobility Ltd v High Speed Two (HS2) Ltd,1 Siemens applied for permission under CPR 35.4(1) for each party to adduce and rely upon evidence from an independent expert witness in the field of rolling stock dwell time, door configuration, seat configuration and rolling stock platform interfaces. The judge refused the application on the grounds that it was neither reasonably necessary nor proportionate to permit expert evidence in these disciplines to be adduced to resolve any of the issues to be determined at trial and that such evidence would not otherwise assist the court to resolve any of the pleaded issues.

When expert evidence is permitted, the courts will still continue to monitor the product: in Radia v Marks2 the judge criticised the evidence of both experts for ranging far beyond the confines of the court’s directions, concluding that the expert evidence had provided only marginal assistance in resolving the case. In Barrowfen Properties Ltd v Patel & Others,3 there was a dispute over whether a court’s direction that each party had permission to call one expert in the field of evaluation of finance costs should be construed (and limited) by reference to the correspondence exchanges and the pleadings. Whilst the judge found that the direction was expressed in wide and unambiguous terms and was not so restricted, this judgment illustrates the court’s active approach to policing permissions. An extreme example of this approach was seen in March 2022 in Andrews & Ors. v Kronospan Ltd4 where the court took the drastic step of revoking the claimants’ permission to rely upon the evidence of its expert notwithstanding the significant repercussions of doing so in terms of costs and possible delay to the trial.

In summary, permission for expert evidence remains a matter for the court’s discretion and albeit rarely expressly stated in the court’s directions, the quid pro quo of permission being granted will be compliance with CPR Part 35. 


It is axiomatic that an expert must offer independent opinion evidence as part of his/her duty to the court. Ordinarily, independence will require the expert to have no prior substantive connection with the instructing party, but there are exceptions: for example, in Multiplex Constructions (UK) Limited v (1) Cleveland Bridge UK Limited and (2) Cleveland Bridge Dorman Long Engineering Limited5, the court confirmed that lay witnesses who possess relevant expertise may offer opinion evidence, albeit subject to objectivity challenges.

In Tehrani v Hamilton Bonaduz AG & Ors.,6 the Intellectual Property Enterprise Court was confronted with a similar situation toMultiplex where the claimant inventor/patent owner acted as her own expert witness. The judge found that, in principle, there was no reason why an expert should not be closely connected to the instructing party, (for example, an employee as was the case in in Multiplex) but there was a higher than usual requirement for the claimant to show that acting as expert, her clear and primary duty was to assist the court objectively and truthfully. On the particular facts in this case, the judge found that the claimant’s actions in her capacity as an expert did not provide the necessary indication of her objectivity. 

Notwithstanding the principle endorsed by the judge, expert evidence offered by employees, family members or close associates will always attract enhanced criticism based upon a perceived want of independence7 and the experts themselves will probably find it more difficult to demonstrate impartiality. 

In Coldunell Ltd v Hotel Management International Ltd8, the claimant’s expert in a dilapidations dispute was familiar with the property having first been instructed some years before to deal with an insurance claim and having acted as the contract administrator for preceding external works and boiler repairs. The judge did not accept the defendant’s criticisms, finding that the duality of roles did not prevent the expert from providing genuinely held independent expert opinion to the court and given that a relatively modest sum of around £1 million was at stake, it was reasonable and proportionate for the claimant to be allowed to rely on the expert’s detailed knowledge of the condition of the property and works required.  In this instance, the claimant’s expert was able to demonstrate objectivity (in contrast to his opposite number – see below).

A novel aspect of the requirement for expert independence was considered in Radia v Marks.9 In this case, Mr Radia claimed damages against Professor Marks – who had acted as a single joint expert in employment appeal tribunal proceedings – for failing to notice discrepancies in Mr Radia’s medical notes, which led to the failure of Mr Radia’s discrimination disability claim against his employers. The judge dismissed Mr Radia’s claim stating that an expert did not owe a duty to protect his or her instructing party from the risk of an adverse finding on credibility: any such duty would create a real conflict with the expert's overriding obligation to the court to provide an independent view. That appears to be a manifestly sensible outcome.

Unopposed expert evidence

Possibly one of the most significant cases over the last 12 months concerning expert evidence was the Court of Appeal’s judgment in October 2021 in Griffiths v TUI (UK) Ltd.10 At first instance, the claimant had relied upon an expert’s report prepared by one Professor Pennington. Having failed to call any expert evidence of their own or required Professor Pennington to attend for cross-examination, TUI critiqued the adequacy of his report’s reasoning in their written closing submissions:  the judge dismissed Professor Pennington’s evidence and the claim. 

By a majority verdict, the Court of Appeal confirmed that there was no strict rule that prevented a court from considering and rejecting the contents of an expert's report which complied with Part 35, even if it had not been challenged by contrary evidence or cross-examination. 

This was a controversial outcome, not the least because of the points made in the dissenting judgment of Bean LJ who expressed the view, in terms, that a fair trial required expert evidence to be challenged by peer evidence or cross-examination and that, in principle, uncontroverted evidence should generally be accepted by the court.

It does seem inequitable that an expert should be deprived of the opportunity to answer criticisms made for the first time in the closing submissions, with the other side having declined the opportunity to challenge the expert’s evidence at any preceding stage. We can, at least, say that this is probably an unlikely scenario in construction disputes, where in most cases there will be opposing expert evidence that will have been challenged in detail at an early stage. 

Expert (mis)behaviour

The last 12 months have seen a fresh crop of expert witnesses who have been censured by judges for failing to comply with CPR Part 35 and the Practice Direction. It must, however, be said that, in two of these cases, the experts’ instructing solicitors also had their wrists slapped where both featured revelations of collaboration between experts and solicitors over the contents of the experts’ joint statement. 

In Andrews & Ors. v Kronospan Ltd,11 the Senior Master revoked the claimants’ permission to rely on the evidence of their dust analysis and modelling expert where disclosed documents showed that the expert had sought input from instructing solicitors during the process of agreeing the joint statement (and also appeared to regard himself an advocate for the claimants). The Senior Master concluded that, in view of these serious transgressions by the claimants’ solicitors and expert, it was not disproportionate to revoke the permission for the expert’s evidence in order to preserve the integrity of the experts’ discussion process and to ensure that the court's decisions were based on objective expert evidence.

In Pickett v Balkind,12 the claimant’s solicitors inadvertently disclosed a letter that alluded to exchanges between the solicitors and expert concerning the joint statement. The claimant applied for an injunction to restrain the defendant from using the letter in evidence but this application was dismissed: the judge agreed with the defendant that the letter revealed a potentially serious breach of paragraph 13.6.3 of the TCC Guide (which provides that the parties' legal advisers must not be involved in negotiating or drafting the experts' joint statement) so the relevant parts of the letter could not be privileged.  This case has not yet come to trial but the ramifications of the claimant’s expert being cross-examined by reference to a letter indicating the malleability of his professional opinions can be imagined.

Several other judgments over the last 12 months have featured acts or omissions by experts that have diminished, sometimes irretrievably, the value of their evidence to the court (and their clients). For example:  

  • In Coldunell Ltd v Hotel Management International Ltd,13 the judge rejected the defendant’s expert’s evidence on several grounds including that he had never physically inspected the property, had relied on argument rather than opinion and had made statements that demonstrably lacked credibility.
  • In Struthers & Another v Davies (t/a Alastair Davies Building) & Another,14 the judge criticised an expert whose views were largely derived from looking at photographs rather than from a site visit and whose quantum calculations were not transparent.
  • In Gallagher v Gallagher (No.2) (Financial Remedies),15 the judge considered that the husband’s expert was not impartial including on grounds that the expert had used the words “we can argue” in emails  and had been forthright, abrasive and adversarial during the hot-tubbing sessions to the extent of rebuking the court for allowing what he regarded as excessive detail from the wife’s expert.
  • In Davies-Gilbert v Goacher,16 the judge criticised an expert who had disregarded the instructions he had received from the court and his instructing solicitors in order to ignore evidence which did not support his opinion.
  • In Reynolds v Stanbury CSB 123 Ltd,17 the judge dismissed the evidence of an expert on several grounds including that his report was an “… unimpressive, results-driven piece of work” with findings that the expert could not justify in cross examination, creating the impression that the expert was treating the giving of evidence in court as a game. 


Judgments that touch upon expert evidence illustrate best practice (for both experts and solicitors) often through stark examples of what not to do. Over the last 12 months, the courts have reinforced some of the more obvious “do nots” for expert evidence: experts should not ask solicitors for input into the joint statement, experts should not use collective pronouns when referencing their client’s arguments and, in a specific construction dispute context, experts should not offer opinions on a site they have never visited. 

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  • 1. [2022] EWHC 2190 (TCC) (17 August 2022).
  • 2. [2022] EWHC 145 (QB) (26 January 2022).
  • 3. [2022] EWHC 207 (Ch) (3 February 2022).
  • 4. [2022] EWHC 479 (QB) (7 March 2022).
  • 5. [2008] EWHC 2220 (TCC).
  • 6. [2021] EWHC 3457 (IPEC) (22 December 2021).
  • 7. Like Caesar's wife, experts must be seen to be above suspicion.
  • 8. [2022] EWHC 1290 (TCC) (27 May 2022).
  • 9. Ibid.
  • 10. [2021] EWCA Civ 1442 (7 October 2021).
  • 11. Ibid.
  • 12. [2022] EWHC 2226 (TCC) (25 August 2022).
  • 13. Ibid.
  • 14. [2022] EWHC 333 (TCC).
  • 15. [2022] EWFC 53 (13 June 2022).
  • 16. [2022] EWHC 969 (Ch) (28 April 2022).
  • 17. [2021] EWHC 2506 (Ch) (23 September 2021).