Harman undertakings in cross-border disputes: Full Federal Court gives guidance on collateral and permitted purposes

Australian companies increasingly navigate disputes that straddle multiple jurisdictions. When documents are produced under compulsion in one court, questions arise as to whether and how those materials may be used to address related issues abroad.

In cross-border disputes, the Harman undertaking can come into focus when parties seek relief in a foreign court. The "relevant circumstances" and differences in procedure and process muddy the determination of purpose and factual overlaps.

The Full Federal Court has recently confirmed that the Harman undertaking or Hearne v Street obligation is assessed by reference to a connection-based purpose –a document obtained under compulsion may be used abroad (even in what is technically another proceeding) where the purpose is not unconnected or unrelated to the underlying dispute – rather than a focus on what the use of the disclosed documents was, or information in the specific proceeding in which it was disclosed (Marsh Limited v Greensill Bank AG [2025] FCAFC 186).

What is a Harman undertaking or Hearne v Street obligation?

Hearne v Street is commonly understood to mean that a party cannot use discovered documents, without leave of the court, “for any purpose other than that for which [the discovery] was given”, unless they were received into evidence. A release is generally granted only in special circumstances through a balancing exercise, where the court considers the nature of the material produced, whether the documents are for the purpose of the proceeding in which they were produced, factual overlap between proceedings, and any other relevant factor. A balance will then be struck between whether the needs of justice are better served by relieving or maintaining the Harman undertaking.

Marsh had sought an anti-suit injunction on an urgent ex parte basis before the English courts, after receiving a notice of intention to join Marsh entities to the Greensill Proceedings in the Federal Court of Australia. In light of its duty of full and frank disclosure to the English court, Marsh believed it necessary to disclose all material facts, both favourable and unfavourable, that were relevant to the application. This included documents discovered by the Respondents in the Greensill Proceedings which were in Marsh Limited's possession, and which it had permitted Marsh Pty Ltd to have access to for the purpose of bringing its Anti-Suit Application. They were twelve documents among approximately 221,000 documents produced by Greensill Bank AG. (Neither Marsh entity had sought or obtained a release from the Hearne v Street obligation before reviewing that discovery material or before referring to and relying on it in their evidence and submissions in the Anti-Suit Application).

The English Court granted an interim anti-suit injunction to restrain the Respondents from joining Marsh Limited to the relevant Greensill Proceedings in Australia but did not impose any restraint in respect of Marsh Pty Ltd. The Respondents subsequently raised concerns with the Marsh entities about the basis on which the interim relief was granted.

The primary judge in Australia characterised the permitted purpose of discovery as conduct of the Australian Greensill proceedings, and treated the English anti-suit injunction application as the "antithesis" of and was "well outside" the permitted purpose of the discovery, as the English injunction sought to prevent the Federal Court from exercising its jurisdiction. His Honour accepted that a stay application in Australia, should Marsh be joined, would have been different and could have used the discovery material without breaching the Harman undertaking.

After receipt of the Australian first instance decision, the English Court discharged the interim anti-suit injunction given in favour of Marsh Limited in respect of all periods (save for a one year period covered by an engagement letter).

Marsh appealed the primary Federal Court decision. The Full Federal Court allowed Marsh's appeal, with the Court finding no breach of the Harman undertaking when Marsh used documents obtained via discovery in the Australian Greensill proceedings to support its ex parte anti-suit injunction application in the English High Court.

In doing so, the Full Federal Court reframed the Harman undertaking's scope, emphasising that the relevant question is whether the use is "connected with" or "related to" determining the same underlying dispute, and not whether the use is confined to the precise proceeding in which disclosure was made. The Court found that the cross-border use of Australian discovered material was deemed sufficiently part of conducting the same dispute in the anti-suit injunction application in the English High Court, rather than a "collateral use". It viewed the difference between an Anti-Suit Application and a Stay Application as a distinction without a substantive difference in terms of them both being a means to resolve jurisdiction and forum issues.

The Full Court's reasoning in allowing Marsh to use the documents

In allowing Marsh's appeal and setting aside the declaration of breach, the Full Federal Court considered that both a stay application (if sought in Australia) and an Anti-Suit Application (as filed in England) were each directed to resolving jurisdiction for the same dispute – so using discovered material for either application would have fallen within the purpose for which the discovery was given.

The Full Court explained that the inquiry into "the purpose for which [discovery] was given" is context-sensitive and is not mechanically confined to the four corners of the particular proceeding in which the documents were produced.

• Purpose is anchored in context: The Harman undertaking formulation turns on the facts giving rise to the production, and does not of itself, confine the purpose to a single file number or forum. In complex, grouped litigation, this purpose could extend to steps that determine how and where the same dispute will be conducted.

• Connection-based approach affirmed: The Full Court treated decisions concerning freezing orders, preliminary discovery, liquidators' examinations and related administrative processes as "applications and amplifications" of the Harman undertaking, not departures from it. These authorities recognise uses that "flow from" the original proceeding and remain tightly connected to the dispute's determination.

• No substantive difference in litigation conduct: There is no relevant difference between asking the Australian Court to stay a proceeding and asking the English Court to prevent a party from invoking the Australian Court's jurisdiction – both concern the conduct of litigation and what claims may be pursued.

• Application to the facts: Using the Greensill discovery material to meet the English ex parte duty of full and frank disclosure on a connected Anti-Suit Application did not breach the Harman undertaking – the same conclusion was applied to Marsh Pty Ltd given the Harman undertaking bound it, and access to the discovery material was only via legal representatives.