High Court grants permission to rely on inadvertently disclosed privileged documents where the mistake was not obvious

The High Court has granted claimants permission to rely on certain privileged documents that the defendant said had been disclosed in error, where it found that the error would not have been obvious to a reasonable solicitor carrying out a proper disclosure review. Permission was refused for other documents, where the mistake would have been obvious: The New Lottery Company Ltd v The Gambling Commission [2025] EWHC 1058 (TCC).

The decision confirms that, as a starting point, a reviewing party is entitled to assume that documents disclosed (even privileged documents) were deliberately disclosed. However, where a privileged document has been produced inadvertently, the opponent will be able to rely on it only with the court's permission. There are no rigid rules, but the court is more likely to refuse permission if there was an obvious mistake - which depends on whether it would have been obvious to a reasonable solicitor (ie an objective test).  The subjective views of those reviewing the documents will be a relevant, and potentially important, factor in the court's assessment, but the weight given will depend on the status and experience of those conducting any particular level of review.

This case highlights some practical takeaways for parties engaged in complex and extensive disclosure exercises – apart from the obvious need to review documents carefully for privilege, including checking for consistency in applying redactions across multiple versions of a document:

• Where a party's disclosure contains documents sent to, received by, commented on or authored by in-house counsel, particularly where the in-house counsel team is extensive, it may be prudent to provide the receiving party with a list identifying the relevant individuals.
• Where it is clear that multiple versions of a document have been disclosed, and a version contains privileged advice which may have been disclosed unintentionally, it would be reasonable for the receiving party to check at least one other version to see if the disclosure appears to be deliberate.
• Where the nature of an issue for disclosure might lead to a reasonable assumption that the disclosing party may wish to produce privileged documents, it should make clear whether or not it intends to do so.

The decision is also of interest in highlighting a potential tension between the test of obvious mistake and the wording of Practice Direction (PD) 57AD, which applies in most cases in the Business and Property Courts. Paragraph 19.2 of the PD provides that a party who "is told, or has reason to suspect", that a document has been disclosed inadvertently must promptly notify the disclosing party and follow their directions as to the return or destruction of the document, subject to any court order to the contrary. The court in the present case noted that the PD did not apply, because there is an exception for procurement cases. It expressed the view, however, that the PD cannot mean the court will no longer give weight to a solicitor's consideration of whether there has been a mistake.

Background

The underlying proceedings concerned the circumstances in which the Fourth National Lottery License was granted to Allwyn.

In the weeks following the Gambling Commission's production of documents, it wrote to the claimants on a number of occasions identifying various tranches of documents that it said contained privileged content and had been produced in error without redactions. In this correspondence, it made clear that it had not intended to waive privilege in providing the documents identified, but did not indicate that there had been any widespread failure in disclosure. It was not until almost two months following production of the first tranche of disclosure that the full extent of the issues became clear. In total over 4,000 wholly or partially privileged documents were said to have been produced in error without, or with incomplete, redactions.

Before the claimants were informed of these issues, their legal team had reviewed many of the alleged inadvertently disclosed documents and had shown some to their clients. The claimants sought the court's permission to use the documents, including for the purpose of amending pleadings. By the time of the hearing, the parties had narrowed the dispute to 128 documents grouped into 20 categories.

Decision

The High Court (Jefford J) granted the claimants permission to rely on only some of the inadvertently disclosed documents.

Relevant legal principles

Before addressing the specific documents sought to be relied on, the court provided an overview of the law relating to inadvertent disclosure of privileged materials. CPR 31.20 provides that, where privileged documents have been inadvertently produced, the receiving party may only use the documents, or their contents, with the court's permission. It was common ground that the principles set out in Al Fayed v Commissioner of Police of the Metropolis [2002] EWCA Civ 780 apply in this context, although that case concerned an application for injunctive relief to prohibit the use of inadvertently disclosed documents rather than an application under CPR 31.20.

Jefford J summarised the 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 summed up the matters that may arise and be taken into account:

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

Given the complexities of electronic disclosure, 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 of review. The judge said this was not inconsistent with Leggatt J's comment in Mohammed v Ministry of Defence [2013] EWHC 4478 (QB), to the effect that mere suspicion or doubt does not oblige the reasonable solicitor to make further enquiries of the disclosing party before making use of the documents. That did not preclude the proper approach being, in some circumstances, to make further enquiry within the disclosed documents.

The judge rejected the claimants' submission that the relevant time for considering the position of the reasonable solicitor must be the first review. That submission elided 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.

In the present case, both parties had carried out reviews at different tiers, with a system for escalation to a core team of solicitors. The judge commented that there was nothing wrong with this – it was "an appropriate and proportionate approach to the review of this type of disclosure". In a disclosure exercise that uses different levels of review, the objective question, at any level, remains:

"whether it would have been obvious to a reasonable solicitor, who should be assumed to be one with a reasonable level of knowledge of the case, that a document has been disclosed inadvertently – that is both that it was privileged and that it had not been disclosed deliberately".

However, the court may attach different weight to the assessments arrived at by each reviewer depending on their status and experience and the directions they had been given.

Two further issues arose in this case. The first concerned the knowledge the reasonable solicitor is assumed to have in cases that relate to a specific field of law, such as procurement. The court accepted that the reasonable solicitor should be one with a reasonable level of knowledge of practice in the particular field of law relevant to the dispute.

The second, which the court noted was very much case specific, but which is likely to arise in many cases, related to knowledge of the Gambling Commission's in-house legal team. It was not clear from the face of certain documents that they had been copied to or commented on by members of the legal team (for example because initials were used, or individuals were not identified as such). The claimants argued that they could not have been expected to know that people not specifically identified as such were lawyers, so that there was nothing in their involvement in documents or correspondence that indicated the content was privileged. The Gambling Commission asserted that it was or ought to have been obvious to the claimants who the legal team were and what their input and involvement was because other disclosed documents did identify certain individuals as lawyers. As to this, the court commented:

"The effect of the submission seems to me to be that… it was incumbent on the claimants to identify from every available document the members of the [Gambling Commission's] in house legal team, produce and circulate a list to all reviewers, and direct the reviewers to be alert [to] the possibility of comments by persons with those initials. Particularly where the [Gambling Commission] had done nothing to identify their own legal team, that is well beyond what the reasonable solicitor could be expected to do and does not assist in setting the standard by which the obviousness of a mistake should be judged."

Decision on the facts

The court considered the 20 groups of documents in question, asking whether it should have been obvious to the claimants that the documents were privileged and had been inadvertently disclosed. A sample document from each group was analysed, with the court's decision on that sample document being applied to the group as a whole.

The following issues were common to those documents on which the court granted permission to rely:

• The documents did not appear privileged on their face. As a general point, the court commented that where a document is not obviously privileged it is all the less likely that the reasonable solicitor should have concluded that it had been inadvertently disclosed.
• It was not obvious that certain authors, recipients or commentators were lawyers. Again, the court commented that, given the scope of disclosure, it would have been sensible for the Gambling Commission to have identified its in-house legal team through provision of a list. The court repeated that a reasonable solicitor should not be expected to search out the identities of an in-house legal team where the other party has not sought to identify them.
• The documents were more commercially focused and did not disclose the content of any legal advice. In one such case, multiple versions of the same document had been produced with only one version containing redactions, which also pointed to a lack of intention to assert privilege over such content.
• While some documents noted that legal advice was being sought, including the topics on which such advice was sought (the fact of which was directly relevant to a disclosure issue), they did not disclose the content of any legal advice.

The following issues were common to those documents on which the court refused permission to rely:

• The documents were clearly seeking, or recording, legal advice or were part of the continuum of communication to enable the provision of such advice. These documents remained legally privileged despite some being shared confidentially with individuals at external organisations.
• The documents were marked "legally privileged" and contained summaries of information that were stated to be derived from legal advice.
• Inconsistent redactions applied to multiple versions of the same document. The judge said there is no overarching approach to be taken to inconsistent redactions, but if a version of a document contains privileged advice and there is a possibility that disclosure was unintentional, the reasonable course would be to check at least one other version. If there is consistency, this would support the view that disclosure was deliberate; if there was inconsistency, it would support the opposite view.
• The documents were clearly authored by, sent or received by, or commented on by external lawyers or the Gambling Commission's General Counsel (whose role as a lawyer was obvious).