The Dekagram: 20th October 2025

In this week’s Dekagram Linda Nelson and John Schmitt consider the recent judgment of Perrin v Walsh (Rev1) [2025] EWHC 2536 (KB) (09 October 2025). Linda discusses when surveillance evidence may be relied upon, while John considers when the court will make an order for the inspection of a draft report by an expert.

Balancing Conflicting Factors in Surveillance Evidence Applications: the Key Issues for a Court to Consider

In what circumstances is it appropriate for a court to give permission for a party to rely on surveillance evidence? The judgment in Perrin v Walsh[1], handed down earlier this month, concerned the defendant’s application for permission to rely on surveillance footage, which the claimant objected to on the basis that the footage had been deliberately and cynically manipulated to paint her as less disabled than she claimed and to bolster the defendant’s allegations of exaggeration.

The claimant was injured in a road traffic accident and suffered multiple injuries. On her case, her injuries extended to possible mild traumatic brain injury, post traumatic stress disorder and functional neurological disorder. The surveillance of her was conducted over 2 years by a surveillance company. The claimant’s objections to that footage were:

• The footage had been edited to remove any footage supportive of her injuries;
• Filming was deliberately stopped at times when she was manifesting symptoms;
• The footage of one surveillance operative had not been provided;
• The SD cards used to record the footage had not been retained and could not therefore be forensically examined.

The defendant accepted there were some failings on the part of the surveillance company, but argued that any prejudice to the claimant was far outweighed by the probative nature of the evidence.

The High Court identified the key factors to be taken into account when deciding whether to give permission to the defendant to rely on the surveillance evidence. These were:

• the basic principle that ‘Surveillance evidence has long been a legitimate weapon, when properly obtained and legitimately used, for a defendant to put before a court that may demonstrate that a claimant’s evidence is false’ (Douglas v O’Neill[2]);
• the Court’s power to control and exclude evidence (CPR 32.1);
• how the probative value of the surveillance evidence weighs against the prejudice created by the failings alleged by the Claimant. On this point, the Court considered a number of earlier judgments outlining the approach to be taken when deciding whether to give permission. In particular:
  • The starting point is that, where the defendant alleges that the video evidence undermines the case of the claimant to an extent that would substantially reduce the award of damages, it will usually be in the overall interests of justice to admit the evidence, “so long as this does not amount to trial by ambush.” (per Potter LJ in Rall v Hume[3]);;
  • It will not amount to trial by ambush if the Claimant has a fair opportunity to deal with it (Douglas)
  • The primary question for the court is whether justice and fairness require that the surveillance footage should be put to the claimant before the trial judge to enable him to reach a sound conclusion about the true extent of any disability (and the question is not whether to give approval to the method whereby the evidence was obtained) (per Lord Woolf LCJ in Jones v University of Warwick[4]);
  • The legitimate need and public interest that defendants should be able to prevent and uncover unjustified, dishonest and fraudulent claims should outweigh the consideration of the claimant’s privacy (Jones);
  • The weight to be attached to each of those conflicting interests will vary according to the circumstances. The significance of the evidence will differ as will the gravity of the breach of Article 8 [ECHR right to a private life]. Relevant factors may include: the conduct of the defendant in obtaining the footage and whether it would be artificial and/or undesirable for the footage not to be placed before the trial judge (e.g. because it would necessitate instruction of new medical experts; or  would mean relevant evidence has to be concealed from the medical experts, perhaps resulting in a misdiagnosis; or would preclude appropriate cross-examination of the claimant) (Jones);
  • The limitations of surveillance evidence, which should be viewed as ‘only a piece of evidence in the jigsaw’. “… if something is shown on the footage, that is determinative of it happening. However I do not accept that the absence of something on the footage is determinative of it not happening.” (Cullen v Henniker-Major[5]).

As part of the balancing process in Perrin, the Court found that there could be no real dispute that the surveillance footage was of probative value as to the claimant’s level of functioning and disability, and cited, without making any findings, the defendant’s assertions about numerous inconsistences between the claimant’s stated disabilities and what is seen in the footage.

The Court then considered the claimant’s allegations about the footage. As to the first allegation (that the footage had been edited to remove any footage supportive of her injuries), having read statements from the surveillance operatives, the court found that some of the operatives’ evidence about the editing of the footage was ‘unequivocally untrue’: some original footage had been omitted from the footage served. Further, the court rejected the operatives’ explanation that it was omitted as it simply duplicated served footage and found that the absence of any understandable explanation for its omission was troubling. The errors in the editing of the footage were ‘fundamental and repeated’. However, the court rejected the claimant’s assertion that the omitted footage was helpful to her case and found that it was, at most, neutral, and further rejected the allegation that the editing was part of a deliberate and dishonest attempt to provide a misleading picture of the claimant’s (dis)abilities.

The court rejected the second allegation (that there was a dishonest attempt to selectively film the Claimant), accepting that the operatives would occasionally have to stop filming in order to avoid detection.

In relation to the third allegation (that the footage of one surveillance operative had not been provided) the Court found that it was entirely unsatisfactory that the footage was not disclosed but rejected the claimant’s contention that it had been deliberately suppressed.

When considering the fourth allegation (that the SD cards used to record the footage had not been retained and could not therefore be forensically examined), the court accepted the operatives’ evidence that the complete footage was backed up securely and, noting the conclusion of Field J in Noble v Owens[6]that the unavailability of the original footage on the SD card(s) was not a bar to the defendant relying on the surveillance evidence, held that the wiping of the raw data from the SD cards was neither wrong nor improper.

Applying those findings to the list of factors to be considered (set out above), the court found that although the failings by the surveillance operatives were serious and were ‘not far away’ from being such poor conduct that the threshold for excluding the evidence under CPR 32.1 was reached, it would be artificial and undesirable for the evidence, which was relevant and admissible, not to be placed before the trial judge and it would be manifestly unfair to the defendant to deprive them of the ability to place the surveillance material before the trial judge. It was relevant that the claimant had sufficient time to deal with the surveillance footage by providing evidence in response to that evidence, and that the experts would have an opportunity to consider and provide comments on the evidence (i.e. there was no ambush). The claimant would be able to cross-examine the operatives and make submissions as to the reliability of the evidence, and it is for the trial judge to decide what weight to give the evidence.

A previous Deka article (‘Service of Surveillance Footage and Statements responding to allegations of Fundamental Dishonesty – some Procedural Pointers’  The Dekagram: 19th May 2025 – Deka Chambers – Barristers Chambers) concerned the case of Matthews v Wye Surgery[7] and highlighted that so long as a claimant is able to respond to evidence (e.g. with their own statement and cross-examination of surveillance operatives at trial), surveillance footage is likely to be admitted (so long as it is served reasonably expeditiously and not too late in the day). The judgment in Perrin supports that conclusion. Whilst the conclusion is not likely to be welcomed by claimants, the Perrin judgment also made an interesting observation as to costs, noting the judgment of Lord Woolf in Jones that:

“Excluding the evidence is not, moreover, the only weapon in the court’s armoury. The court has other steps it can take to discourage conduct of the type of which complaint is made. In particular it can reflect its disapproval in the orders for costs which it makes… In addition, we would indicate to the trial judge that when he comes to deal with the question of costs he should take into account the defendant’s conduct which is the subject of this appeal when deciding the appropriate order for costs. He may consider the costs of the inquiry agent should not be recovered. If he concludes, as the complainant now contends, that there is an innocent explanation for what is shown as to the claimant’s control of her movements then this is a matter which should be reflected in costs, perhaps by ordering the defendants to pay the costs throughout on an indemnity basis.”

About the Author

Linda Nelson was called in 2000 and is ranked in both the Legal 500 and Chambers and Partners for her personal injury and travel law work. Linda regularly advises in international personal injury cases with cross-border issues, particularly those falling within the jurisdiction of the Admiralty Court. She is well-versed in claims involving the international carriage conventions, the package holiday regulations, Merchant Shipping regulations, ship collisions and issues of jurisdiction, applicable law and limitation. She is a contributing author to Munkman on Employers’ Liability (writing the ‘Shipping and Workers on Ships’ chapter) and co-authored ‘Work Accidents at Sea’ (now in its second edition).

Disclosing Draft Reports: When Will the Court Make an Order for Inspection?

John Schmitt considers the further interesting aspect of Perrin v Walsh (Rev1) [2025] EWHC 2536 (KB) (09 October 2025) that addresses the Claimant’s application for specific disclosure (in reality, inspection) of draft report prepared by the neuropsychologist expert instructed by the Defendant, Dr Mullin.

The Basis for the Application

The background to the Claimant’s application was her argument that Dr Mullin had materially changed his position on a central issue in the case, namely the effort applied by the Claimant to neuropsychological tests performed by Dr Mullin. The basis for the Claimant’s assertion was twofold in that Dr Mullin’s served reports did not contain passages of text quoted in –

• the Defendant’s original Defence pleading fundamental dishonesty (namely that the Claimant has failed two of three TOMM trials administered by an unusually large margin); and
• the served report of Dr Jarman, the neurologist instructed on behalf of the Defendant, which referred to Dr Mullin’s report of a date August 2024, and which was provided as part of his instructions, and which quoted Dr Mullin in its statement that the Claimant failed a test of performance validity.

In fact, Dr Mullin’s served report within the proceedings was dated December 2024 and now stated that the Claimant passed the tests of Performance Validity administered and that there was no indication of intentional underperformance upon testing. Further, Dr Mullin’s position appeared to change from there being two trials failed to one trial that was failed.

The Defendant opposed the application on the basis that the draft report was privileged given that it was in draft.

The Relevant Rules

CPR r. 31.14(1) states as follows:

• A party may inspect a document mentioned in –
• a statement of case;
• a witness statement;
• a witness summary; or
• an affidavit.”
• Subject to rule 35.10(4), a party may apply for an order for inspection of any document mentioned in an expert’s report which has not already been disclosed in the proceedings. (Rule 35.10(4) makes provision in relation to instructions referred to in an expert’s report).”

CPR 35.10 states:

• An expert’s report must comply with the requirements set out in Practice Direction 35.
• At the end of an expert’s report there must be a statement that the expert understands and has complied with their duty to the court.
• The expert’s report must state the substance of all material instructions, whether written or oral, on the basis of which the report was written.
• The instructions referred to in paragraph (3) shall not be privileged against disclosure but the court will not, in relation to those instructions— (a) order disclosure of any specific document; or (b) permit any questioning in court, other than by the party who instructed the expert, unless it is satisfied that there are reasonable grounds to consider the statement of instructions given under paragraph (3) to be inaccurate or incomplete.

The Relevant Case Law (in summary)

The court was also referred to three specific cases that deal with the issue of privilege, disclosure and inspection in relation to draft expert reports:

• Lucas v Barking, Havering and Redbridge Hospital NHS Trust [2004] 1 WLR 220: here, CPR r.35.10(4) was said to strike an important balance between on the one hand the protection of the party whose privilege is lost, and on the other the vindication of 35.10(3) where there is a real question-mark as to its fulfilment.
• Jackson v Marley Davenport Ltd [2004] EWCA Civ 1225; [2004] 1 WLR 2926: here, the Court of Appeal unanimously upheld the position that a draft expert report is privileged, subject to the provisions of CPR 35.10.
• Pickett v Balkind [2022] EWHC 2226 (TCC); [2022] 4 WLR 88: here, the issue was whether inspection should be permitted of a draft report not served in proceedings that an expert had subsequently relied upon as part of their opinion within the expert joint statement.

Judicial Recapitulation

The judge helpfully summarised the relevant principles:

1. The starting point is that a draft expert report is privileged (i.e. subject to litigation privilege).
2. Merely mentioning a draft expert report will not usually, in and of itself, waive privilege on that draft expert report.
3. Where the report of ‘Expert A’ is provided to ‘Expert B’ for the purposes of providing evidence upon which ‘Expert B’ may base their opinion, a party to the proceedings may apply to the Court for an order for inspection of that document in the same was as any other document. Where Expert A’s report was provided to Expert B as part of the instructions to Expert B, it would not usually be privileged but would only usually be ordered to be produced if the court were satisfied of reasonable grounds to consider the statement of instructions set out by Expert B was inaccurate or incomplete. If the report was not part of the instructions to Expert B, then it falls outside CPR 35.10(4), and is likely to be privileged, which means that the court can order its production only if privilege has been waived.
4. When deciding whether privilege has been waived, the court needs to consider whether Expert A’s report has merely been mentioned or whether the content of Expert A’s report has been relied upon or deployed by Expert B (or a party). In the former case, privilege would not normally have been waived. In the latter case, reliance or deployment would in principle be capable of operating as a waiver of any privilege in that material.

Analysis & Decision

Importantly, here, the Defendant was no longer relying on its Defence alleging fundamental dishonesty and therefore there was no longer any pleading that referred to the draft report. Hence the document was no longer referred to in a statement of case and thus the Claimant could not satisfy r.31.14(1)(a).

As to Dr Jarman having considered Dr Mullin’s report, the judge considered himself bound by the decision in Lucas (above). That is clear that an opposing party is not entitled to inspection of a draft expert report even where that draft has been referred to in the served reports of the same expert, or another expert, subject to compliance with CPR 35.10(3).

The court actually went further to note it was reassured that Dr Jarman had taken steps to identify elements of another expert’s report that ultimately went against the conclusion he reached: “this is a sign of an expert taking care to consider the material before them and reassures (the court) that, was there anything else of substance in the draft report upon which Dr Jarman relied or impacted upon his opinions, he would have referred to them. This is part of the Part 35’s expert’s duties to the Court and the Court has to place faith in the expert that they will fulfil those duties, as enunciated by Laws LJ in Lucas.”

There remained a significant curiosity in this situation as to how Dr Mullin had come apparently to change his opinion markedly on the Claimant’s performance test results. However, the court held nothing really turned on this: the draft report of Dr Mullin was not used by Dr Jarman as a springboard for his own conclusions; further, Dr Mullin himself, within his served report, has now opined that the Claimant did not fail such testing. That is the evidence that is now before the Court; conversely, his previous and apparently different opinion was not before the court and not relied upon.

Comment

This provides a helpful summary of the relevant civil procedure and case law on this scenario.

The outcome seems perhaps unsatisfactory (given Dr Mullin appears to have changed opinion strikingly) but is consistent with principle. The Defendant’s position was greatly assisted by the fact it had retreated from its original pleading of fundamental dishonesty and, relatedly, that the experts were not relying on each other’s opinions to question the Claimant’s credibility. In this sense, it was a somewhat unusual application by a Claimant to try to force disclosure of an opinion that probably undermined her.

It also reduced the court’s assessment of the jeopardy of the issue at stake, something always relevant to an exercise of the court’s discretion.

The court was plainly anxious that permitting inspection of draft reports in these circumstances would risk opening the type of satellite litigation that Waller LJ was seemingly eager to avoid in Lucas.

The door was left open for the Claimant to be able, potentially, to question Dr Mullin on his change of opinion at trial, presumably to try to weaken his position as an expert of consistency and credibility; this judge left open the question of whether that would be permissible as a matter for consideration by the trial judge.

About the Author

John Schmitt was called in 2013 and now specialises in complex personal injury work. He is also experienced in representing families at inquests in a clinical negligence context and has done so through the AvMA pro-bono inquest service. Most recently he has represented a family at a four day jury inquest at the conclusion of which the deceased’s employer was ordered to produce a Prevention of Future Deaths report. He is described by the Legal 500 as having a ‘lovely manner about him’ but being ‘as sharp as a tack’.

[1] [2025] EWHC 2536

[2] [2011] EWHC 601

[3] [2001] EWCA Civ 146

[4] [2003] EWCA Civ 151

[5] [2024] EWHC 2809 (KB)

[6] [2011] EWHC 534 (QB)

[7] [2025] 4 WLUK 520