Guidance on inadvertent disclosure of privileged material in large-scale disclosure exercises

In The New Lottery Company Ltd & Anor v The Gambling Commission> [2025] EWHC 1058 (TCC), the High Court considered the claimants’ application for permission to rely on certain privileged documents that the defendant said it had disclosed in error. The claimants were permitted to rely on some of the documents where the Court found that the error would not have been obvious to a reasonable solicitor carrying out a proper disclosure review.

This decision is notable because the cases on inadvertent disclosure of privileged material by a party generally relate to a more traditional disclosure review. Here the Court had to apply the established principles to an extensive disclosure exercise with several tiers of review by legal personnel with varying levels of experience and knowledge of the case, and where the disclosure included a substantial number of electronic documents, multiple versions of the same document and repetitive email chains. The judgment offers practical guidance for parties involved in such extensive disclosure exercises, as discussed further below.

Background

The underlying dispute relates to the claimants’ procurement proceedings against the defendant, The Gambling Commission, in relation to the grant of the Fourth National Lottery Licence.

Following the defendant’s disclosure of documents, the defendant notified the claimants that there was privileged content within certain of the disclosed documents which had, in error, been provided without the appropriate redactions and that it did not intend to waive privilege. However, it was not until a couple of months after disclosure that the defendant identified the full scale of the errors: over 4000 documents that were wholly or partially privileged had been produced without redactions or with incomplete redactions. By this point, the claimants’ solicitors had already started to review the defendant’s disclosure (including some of the documents identified as having been disclosed in error) and had shown certain individuals at their clients some of the documents. The parties exchanged correspondence about what should happen next which led to the claimants applying to court for permission to use the documents, including for the purpose of amending their pleadings. By the time of the application hearing, the parties had narrowed the scope of the dispute to 128 documents in 20 groups.

Legal principles regarding inadvertent disclosure

Civil Procedure Rule 31.20, which provides that where a party inadvertently allows a privileged document to be inspected the receiving party may only use the document or its contents with the court’s permission, applied to the case (PD 57AD did not apply as the proceedings were procurement proceedings).  It was common ground between the parties that the principles set out in Al Fayed v Commissioner of Police of the Metropolis [2002] EWCA Civ 780 i.e. a court may refuse to allow use of a document where it has been made available as a result of an obvious mistake, applied in these circumstances. Jefford J summarised the relevant principles as follows: “there are no rigid rules but the court is more likely to give permission if it was not obvious that the documents were disclosed as a result of a mistake; the court is more likely to find the mistake obvious if it would have been obvious to a reasonable solicitor; and the reasonable solicitor's conclusion after detailed consideration will be a relevant, and potentially important, factor.”

The Judge noted that both parties’ approach to disclosure was to carry out a review at different tiers where the level 1 review was not necessarily carried out by the sort of solicitor that the authorities on inadvertent disclosure contemplated or one that had the characteristics of the putative reasonable solicitor. However, the claimants and defendant also had a system for escalation to a core team of solicitors. The judge commented that there is nothing wrong with this – it is an appropriate and proportionate approach to this type of disclosure review. However, as the authorities are framed in terms of a more traditional disclosure review, the Court had to apply the above principles to an extensive review of largely electronic documents.

Principles in the context of an extensive disclosure exercise

The Court did not accept the claimants’ argument that, in cases such as this, the point in time at which a court should consider the position of the reasonable solicitor must be the first review. That argument combined two issues: (i) whether the mistake should have been obvious to a reasonable solicitor (an objective test); and (ii) what the apparently reasonable solicitor in fact thought (a subjective question) which the court may regard as an important pointer. Where there is a tiered approach to the review of disclosure, the first review may, as a matter of fact, be carried out by someone who would not properly be characterised as the reasonable solicitor and the answer to the subjective question would be of less relevance than the view formed on a subsequent and different level of review. In this case, the Court considered that the type of review contemplated in Al-Fayed took place when the document was escalated to the core team, and it was that review that was the more relevant pointer for answering the subjective question.

The complexities of an electronic disclosure exercise of this type meant that if there is something in the nature of the document disclosed which ought to alert the reasonable reviewer to the possibility of mistake, they ought to inquire further and/or refer the document to a higher-level review. This was not inconsistent with an earlier authority that provided that mere suspicion or doubt as to a mistake does not oblige the reasonable solicitor to make further enquiries of the other party before making use of the document. That authority did not preclude the proper approach being in cases such as this to consider whether further inquiry within the disclosed documents should be made.

As to the knowledge a reasonable solicitor is assumed to have where the case concerns a specialist field such as procurement law, the Court accepted that the reasonable solicitor should be one with a reasonable level of knowledge of practice in the particular field.

The Court summarised the matters that may be taken into account as follows:

1. The reasonable solicitor is entitled to start from the premise that the documents disclosed have been deliberately disclosed.
2. The reasonable solicitor is entitled to take into account the character of the firm giving disclosure and the manner in which disclosure has been given. A sophisticated exercise undertaken by a highly experienced firm would not be expected to result in inadvertent disclosure of privileged documents.
3. The volume of disclosure is a matter that cuts both ways. On the one hand, it might be said that a vast volume of disclosure would make it more likely that mistakes would be made and, on the other hand, that the court might regard it as less likely that any errors should be obvious to the reasonable solicitor.
4. The reasonable solicitor is one with a reasonable knowledge of the issues in the case and the issues for disclosure. That would include whether there were any matters on which it might reasonably be thought that the disclosing party would disclose documents over which it might otherwise assert privilege.

Application to the facts

The Court applied the above principles to the disputed documents to determine whether it should have been obvious to the claimants that a privileged document had been disclosed by mistake. The Court considered the documents by reference to 6 categories. These categories illustrate the types of issues that created the dispute over whether the mistake was obvious: (i) documents which did not appear obviously privileged to begin with; (ii) documents where there was an identifiable lawyer author/recipient/commentator but it was not obvious that the content was legal advice; (iii) redacted documents which had already been reviewed for privilege and there was no obvious reason to question the redactions; (iv) documents where redaction was inconsistent; (v) documents on which the content was potentially legal advice or reflected the substance of legal advice but it was considered these were deliberately disclosed in response to an issue for disclosure; and (vi) documents which appeared to be legal advice but privilege appeared to have been lost by sharing with a third party.

The Court gave permission to use some documents but not others. Various issues can be drawn out of the analysis.

Identifying authors as lawyers

The Court commented that where the document is not itself obviously privileged it is all the less likely to be the case that the reasonable solicitor should have reached the conclusion that it had been inadvertently disclosed. The claimants argued that it was not obvious that certain authors, recipients or commentators were lawyers so there was nothing to indicate that the content of the document was privileged. They could not be expected to know the identity of the defendant’s large legal team (particularly as in some documents comments appeared with initials but not names, or a name without job title). The Court held that, “when considering the issue of the identity of the legal team, it does not seem to me that the reasonable solicitor should be expected to search out the identity of an in house legal team where the other party has not sought to identify them. That must particularly be the case where it is obvious that the disclosure review is going to be carried out by multiple people and at different levels, and that would have been obvious in this case. There would, of course, be circumstances in which something authored by a member of an in house team was identified as such or was so obviously legal advice that it should lead the receiving party to consider whether it was privileged even though they did not know the names of the in house team. It is a case sensitive question.” In contrast, the Court held that it should have been obvious that certain documents authored or commented on by external lawyers or the defendant’s General Counsel (who the Court considered fell into a different category from other members of the defendant’s legal team) were disclosed in error.

Commercial content or legal advice

A number of documents on their face had been circulated within a commercial team for comment and there was nothing that ought to have alerted the reviewer that privileged advice was being disclosed (particularly where it was not obvious the comments were being made by a lawyer). Similarly, some documents identified issues on which legal advice had been sought but said nothing about advice received; in the context of this case, permission was given to use these documents. However, in contrast some documents were marked as “privileged” or were obviously privileged as they contained summaries that were stated to be derived from legal advice. It ought to have been obvious that they were disclosed in error, and it was not correct to assume that it was more likely that they had been disclosed deliberately in response to a disclosure issue. This is particularly the case where there is nothing in a disclosure issue that might indicate that any privileged advice would be deliberately disclosed; where there is no good reason for the disclosing party to have waived privilege, it is more likely that the mistake will be obvious.

Errors in redactions

Where there are inconsistent redactions to multiple versions of the same document, the Court noted that the authorities provide limited assistance on the approach a court should take where there are multiple reviewers, and what knowledge of the disclosure universe as a whole should be attributed to the reasonable solicitor.  The Court held that there is no overarching approach to be taken to inconsistent redactions but if a version of a document contained privileged advice and there was the possibility that this disclosure was unintentional, the reasonable course would have been to check at least one other version. If there was consistency, that would support the view that the disclosure was deliberate. If there was inconsistency, it would point the other way. However, in another example, where multiple versions of the same document had been produced and only one version contained redactions, this pointed to a lack of intention to assert privilege and the Court did not think it was or should have been obvious that the document had been disclosed by mistake.

Key takeaways

The decision reaffirms that in a disclosure exercise, the starting point is that the reviewing party is entitled to assume that the documents disclosed were deliberately disclosed. It also highlights some practical points for parties engaged in extensive disclosure exercises:

• Where a party’s disclosure contains documents authored or sent to/received by a large in house counsel team, it may be sensible to provide the receiving party with a list identifying members of the team. The Court acknowledged that the provision of such a list is not a normal practice, but given the scope of disclosure and the disclosure of documents that were likely to have been reviewed by lawyers, it would have been a prudent course of action in this case.
• Where there are inconsistent redactions to multiple versions of the same document and a version appears to contain privileged advice, it would be reasonable for the reviewing party to check at least one other version to assess if the disclosure appeared to be deliberate.
• Where there is nothing in a disclosure issue to indicate that any privileged advice would be deliberately disclosed, it is more likely that a mistake should be obvious to a reviewer.