Re-examining a significant issue, the High Court has decided that claims for legal advice privilege are, in principle, subject to a dominant purpose test.  In this context, the court also gave guidance on the approach where emails are sent to multiple addressees.

This is likely to be an issue of particular importance to businesses with in-house lawyers who often wear both legal and commercial hats. Such businesses should ensure that they have robust communication protocols in place to maximise the chances of relevant communications being protected by legal advice privilege. Such protocols should highlight (i) the desirability of keeping legal and commercial email traffic separate; and (ii) the need to avoid indiscriminate copying in of multiple recipients (particularly involving both lawyers and non-lawyers) as this could undermine a claim to privilege. 

R (on the application of Ltd) v Civil Aviation Authority [2018] EWHC 3364 (Admin)


The Civil Aviation Authority (CAA) published a press release in which it criticised for its decision not to participate in its new, voluntary, ADR scheme for passenger complaints. In a letter to the CAA, complained about the press release and explained its reasons for not moving to the new scheme. The CAA responded by letter dated 1 February 2018 (February Letter) in which it criticised further. The Daily Mail then published articles that referred in detail to this correspondence. started judicial review proceedings. As part of these proceedings, the CAA disclosed an initial draft of the February Letter together with the covering email, which had been circulated by a CAA non-lawyer to colleagues including an in-house lawyer. sought specific disclosure under CPR 31.12 of, amongst other things, all drafts of the February letter and internal discussions of those drafts. The CAA invoked legal advice privilege.

Legal advice privilege

Relying on Three Rivers (No 5) in the Court of Appeal, and Three Rivers (No 6) in the House of Lords, the judge held that "…claims for legal advice privilege are, in principle, subject to a dominant purpose test, namely whether the communication or document was brought into existence with the dominant purpose of it or its contents being used to obtain legal advice." This was controversial given the (obiter) comments of the Court of Appeal in SFO v ENRC [2018] EWCA Civ 2006 and academic commentary which cast doubt on the need for a dominant purpose test in relation to legal advice privilege.

Although the dominant purpose test will likely be irrelevant in many cases (for example where an external lawyer is sent material), it can add an additional layer of complexity where material is sent to in-house lawyers, who may have dual commercial and legal roles. Noting that "the mere involvement of a lawyer is not enough to justify a claim for privilege", the judge gave the following guidance:

  • Where the in-house lawyer is clearly being asked for legal advice, privilege is likely to attach.
  • Where the in-house lawyer is being asked about a largely commercial issue, the dominant purpose test will need to be applied.

In relation to an emails sent to multiple addressees, including lawyers and non-lawyers:

  • if the dominant purpose of the email is to seek advice from the lawyer and others are copied in for information only, then the email is privileged, regardless of who it is sent to.
  • if the dominant purpose of the email is to seek commercial views, and the lawyer is copied in (for information or for legal advice) then the email is not privileged.
  • If sent to the non-lawyer for commercial comment, but sent to the lawyer for legal advice then the email is not privileged unless it or the non-lawyer's response discloses the nature of the legal advice.

In this case, any draft of the February Letter created before the CAA's in-house lawyers were consulted was not privileged. Further drafts of the letter "are not covered by privilege unless specifically drafted by the lawyers or for the dominant purpose of obtaining legal advice. Such drafts do not subsequently attract privilege when they were shown to the in-house lawyers".


In a subsequent case ( Limited v Civil Aviation Authority [2019] EWHC 336 (Admin)), the CAA requested permission to appeal arguing there was no dominant purpose test for legal advice privilege. The judge rejected that argument and the other grounds for appeal.

In resisting the CAA's application for permission to appeal, raised an alternative waiver argument. If, contrary to the judge's original decision, the CAA's written discussions of the February Letter were privileged, the CAA had in any event waived privilege in these communications by voluntarily disclosing an internal email from a non-lawyer to three internal addresses, including an in-house lawyer.

The court decided that (i) the purpose of the CAA referring to the email was to show its true mind-set at the time; (ii) the "transaction" (issue) in respect of which privilege was waived was not the email itself but the wider internal discussions/emails in the period between's letter of complaint and the publication of the first article by the Daily Mail; and (iii) fairness required disclosure of the entire chain of discussion.

Dangers of "cherry picking"

The practical effect of this was that, by deliberately disclosing one particular email, the CAA had waived privilege in it "and any other relevant documents recording discussions of the draft February Letter". This is a cautionary reminder about the dangers of inadvertent collateral waiver of privilege across a wider class of documents as a result of cherry picking privileged documents for disclosure. 

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Hannah Bradley

Hannah Bradley

Principal Knowledge Lawyer, Dispute Resolution
Leeds, UK

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