Further developments to the scope of arbitral confidentiality in arbitrations governed by English law

July 2025 | SPOTLIGHT | LITIGATION & DIPSUTE RESOLUTION

Financier Worldwide Magazine

July 2025 Issue

Parties choose to resolve their commercial disputes by way of arbitration for many reasons, notably the perceived advantages which the forum has to offer over traditional court litigation. The fact that the proceedings are conducted in private is often seen as one of the most significant advantages.

While the arbitration itself will be conducted in private, it may not always remain confidential. As a result, parties that choose arbitration under the assumption that documents and information will be protected by an obligation of confidentiality may later be surprised to find out that there are exceptions to this rule.

That reality can of course cut both ways, depending on the circumstances. There is nonetheless significant benefit to be had in first understanding where the boundaries lie. This then enables the parties to plan accordingly, and where necessary, customise the confidentiality obligations within their arbitration agreement and select appropriate arbitration rules to suit strategic objectives.

The balance of this article provides a brief overview of the complex issue of arbitral confidentiality under English common law, and the established exceptions to it, specifically viewed through the lens of commercial arbitration.

The subject has become topical again following a recent decision in May 2025 of the High Court (A Corporation v Firm B & Mr W (2025)). In its judgment, the court examined the general principles of arbitral confidentiality which have emerged from the authorities, and set out its findings by reference to the following questions: what material does the obligation of arbitral confidentiality extend to, and what are the relevant exceptions to that obligation?

That analysis is considered below in summary, supplemented where relevant by further matters established by other jurisprudence.

The starting point is the generally accepted position under English law that parties and arbitrators are taken to be under an obligation of confidentiality as an implied term of the arbitration agreement. Although not signatories to the arbitration agreement, the parties’ legal representatives have been found to be subject to arbitral confidentiality, as have expert witnesses, either as an implied term of their own engagement (where not express), or by being placed on notice of the confidentiality of the arbitration. The position in relation to fact witnesses is less clear, and so good practice requires that they be made aware of the confidential nature of the proceedings by the tribunal and the parties.

The implied obligation alone does not render confidential the fact that a dispute has arisen between the parties, the underlying facts, nor that an arbitration has been commenced to resolve it. Depending on the terms of the parties’ broader contractual relationship, these issues may potentially be protected from disclosure through other means but where not, those matters are in principle, susceptible to disclosure to third parties.

However, authorities do establish that arbitral confidentiality applies by default to the following materials, disclosure of which outside of the arbitration would constitute a prima facie breach of the obligation, unless a relevant exception applies: (i) the hearings in the arbitration, which includes any transcripts or notes of the hearing; (ii) documents disclosed by a party in the arbitration to the other party; (iii) documents generated or prepared for and then used or produced in the arbitration, which would include, for example, the parties’ pleadings, witness statements, expert reports, procedural orders, written submissions and correspondence between the parties (or their representatives), and with the tribunal, relating to the arbitration; and (iv) the arbitral award.

Documents of a party which come into existence independently of the arbitration, but which are then disclosed or relied on in the arbitration, do not become confidential and prohibited from use by that party outside of the arbitration simply because they have been relied on or referred to. Save where an exception applies, it would nonetheless be impermissible for the opponent to disclose such documents to third parties, as they are under an obligation only to use the documents for the purposes of the proceedings in which they have received them.

So far so good. Now here is where potential issues arise.

The implied obligation does not automatically extend wholesale to any court proceedings which become necessary, such as, for example, a challenge to an award or a ruling on a point of law. Depending on the type of issue to be determined, the court may order that an arbitration claim be heard in public or private. If heard in private, it does not automatically follow that the judgment will be private. In all cases, the court has to undertake a balancing exercise between the parties’ expectation of confidence and serving the public interest, including whether and how matters are referred to in any published judgment.

Insofar as the formal exceptions are concerned, there is not a comprehensive list as matters will turn on the relevant context and individual facts, and a full analysis will be required in each case. Broadly speaking, the exceptions have so far been developed by the courts under four non-exhaustive grounds.

The first is where the parties have consented to the disclosure of the relevant documentation or information, either expressly or impliedly. If the parties have agreed in terms that a particular document or piece of information can be disclosed to third parties, then this needs no further discussion. The position can be slightly more nuanced. Without limitation, this would also cover a situation where the parties have agreed, say, to adopt institutional arbitration rules which provide for the publication of awards, without then objecting or opting out of publication.

Secondly, disclosure is permissible where there is an order or leave of the court to disclose. For example, a party in court litigation can seek disclosure of documents generated in an arbitration, but disclosure will likely only be ordered by the court if it is necessary to fairly determine the case. The court has to take into account, when exercising its discretion, the fact that the documents are otherwise confidential in the arbitration, but the fact that they are confidential is not determinative as to whether or not the disclosure can be ordered.

Thirdly, disclosure is permissible where it is reasonably necessary to establish or protect the legitimate interests of an arbitrating party. For example, this has been found to include situations where a party can disclose an arbitration award to establish the existence of an issue estoppel against the same opponent (or potentially, parties related to that opponent) in other proceedings. It has also been found to extend to the use of witness statements, reports and transcripts where a witness (expert or fact) gives evidence which is contrary to evidence they have given in a prior arbitration.

Finally, a broad exception applies where disclosure is required in the interests of justice, or in the public interest. This has been used where maintaining confidentiality would prevent unlawful acts from being identified and which could not be properly pursued without access to the confidential materials.

In A Corporation v Firm B & Mr W, it was also clarified that experience acquired by lawyers in the conduct of an arbitration is also not the subject of arbitral confidentiality, and can be deployed in future matters, even involving related parties. For example, this would include knowledge acquired about the types of documentation which might be available from an opponent on a particular issue, their record-keeping practices, and which disclosure requests have and have not resulted in useful information. As such, it would generally not be a breach of arbitral confidentiality to use such knowledge in later proceedings to tailor document requests on that basis.

The court also went on to clarify that the obligation does not apply to litigation strategies which are typically employed by an opponent, or their general approach to issues. Accordingly, preparing a case on the basis of such knowledge would be permissible. Likewise, lawyers are able to shape cross-examination strategy for a witness who they may have previously cross-examined, or seen cross-examined, in a different arbitration.

Of further note were the comments of the court expressing the view that it is “strongly arguable” to use material which is subject to arbitral confidentiality for the purposes of eliciting fact evidence from a third party that has similar complaints against a common counterparty, in order to test the probity of the case faced. This is a potentially significant broadening of the scope of the exceptions, and it will be interesting to see if and how future decisions address this issue. In the meantime, it will potentially be an issue of concern for parties involved in numerous disputes which share a common factual matrix.

Navigating this complex area of law and assessing particular circumstances against the general principles can be a difficult exercise given the fact-specific nature of the analysis and underlying framework. Parties need to consider whether the default position is adequate for their purposes, or whether provision needs to be made to address specific issues, subject to the common law exceptions. Either way, it cannot be automatically assumed that sensitive information will remain confidential to the arbitration, simply because it is deployed in or related to it.

James Bremen and James Mayers are partners at Joseph Hage Aaronson & Bremen LLP. Mr Bremen can be contacted on +44 (0)7717 341 058 or by email: james.bremen@jha.com. Mr Mayers can be contacted on +44 (0)7753 466 747 or by email: james.mayers@jha.com.

James Bremen and James Mayers

Joseph Hage Aaronson & Bremen LLP