You can’t have it both ways: relying on privileged communications may trigger disclosure

The Competition Appeal Tribunal's (CAT) decision in Newman v Rightmove [2026] CAT 62 is a useful reminder that parties cannot use the contents of legally privileged communications to support their case while at the same time refusing to disclose the documents behind those communications. 

If a party relies on privileged communications in evidence, it may lose the right to keep those communications safe from disclosure (a principle known as ‘Waiver’). Whether a waiver has arisen will depend on the specific facts. The Newman decision confirms that a waiver can arise even where the reference to the privileged communications is relatively ‘opaque’ and where no particular documents recording the communications can be identified. The Tribunal accepted that it was enough to infer that the communications would have been recorded somewhere, such as a file note, or other document. 

This article examines the discussion around waiver of privilege.

Background to the Case

The dispute arose in collective proceedings proposed against Rightmove. The Proposed Class Representative (PCR) sought certification on an opt-out basis and expressly referred to communications with proposed class members (PCMs) in the witness evidence, stating that many PCMs feared commercial retaliation if their identities became known. Those assertions were based on discussions between the PCR's legal team and the PCMs, communications that would ordinarily attract litigation privilege. Rightmove argued that by referencing those discussions within the witness evidence, the PCR had waived privilege and should disclose the underlying communications.  

The Legal Framework 

Adopting the approach in PCP Capital Partners v Barclays [2020] EWHC 1393 (Comm), the Tribunal held that waiver of privilege is a fact-sensitive exercise assessed through the prism of:

1. Whether there is any reliance on the privileged material adverted to. 
2. What the purpose of that reliance is. 
3. The particular context of the case in question.

This analysis involves two stages:

1. The court must decide whether privilege has been waived by a party, (a) referring to privileged communications; and (b), positively relying upon them “in some way to support or advance his case on an issue that the court has to decide”.

2. If waiver has occurred, the court must consider whether it is appropriate to order disclosure of privilege documents other than those to which reference has been made which was the foundation for the waiver? This is driven by fairness, because “if the party waiving is, by the waiver, thereby creating a partial picture only of the relevant [privileged materials], it is unfair to the other party to allow him to ‘cherry pick’ in this way”

    

What happened in Newman v Rightmove?

The Tribunal held that the PCR had relied on communications with proposed class members concerning fears of retaliation. Those communications would ordinarily attract litigation privilege, but they were expressly referenced in witness statements.  

As to purpose, the PCR relied on the evidence to support a key certification issue: that opt-out proceedings were more suitable because a significant number of class members might be reluctant to participate in opt-in proceedings due to concerns of retaliation. The communications were therefore being used to advance the PCR's case on an issue the Tribunal would have to decide. Although the Tribunal acknowledged that the passages were opaque, it was clear that they were intended to address the prevalence of concerns about retaliation among both the sample communicated with and the wider population. 

In relation to the context of the case in question, the Tribunal confirmed the size of the claim and nature meant it was important as a matter of basic fairness for Rightmove to be able to test the credibility of the evidence. Without disclosure, the Tribunal would be left with only the PCR's high-level and untested summary of the communications. 

The Tribunal therefore ordered disclosure of communications concerning the retaliation concerns, including the identities of the relevant class members, subject to a lawyers-only confidentiality ring. However, the PCR was given the alternative of withdrawing the relevant evidence entirely. 

Key Takeaway for Waiver

You can’t have it both ways: 

If a party wishes to rely on privileged materials, it must be prepared for the possibility that those communications, and sometimes related documents (known as collateral disclosure) will have to be disclosed. Parties do not usually give up legal privilege intentionally, but it can happen surprisingly easily during a dispute. 

Even a mere mention, or an accidental reference to a privileged document, can lead to arguments about whether the right to keep those communications confidential has been lost.

Before referring to privileged material in proceedings, parties and their lawyers should carefully consider whether it is necessary. If they do choose to rely on it, they need to be aware that doing so could mean losing the right to keep those communications confidential and may lead to an order to disclose them. In short, a mere reference to privileged material can open the door to a dispute over whether privilege has been waived, with the risk that the court may ultimately require the material to be disclosed.

Written by Stacie Bourton and Jacob Berger