Mann v Carnell

Facts

The plaintiff, Dr Mann, sought documents from the defendant, Ms Carnell (Chief Minister of the Australian Capital Territory), claiming that legal advice had been disclosed to a third party in a manner that waived legal professional privilege. The ACT government had provided legal advice to a member of the Legislative Assembly to explain the government's conduct in relation to the plaintiff's contract. The plaintiff argued that this disclosure waived privilege over related documents.

Issues

1. Whether legal professional privilege was waived by the voluntary disclosure of legal advice to a third party. 2. Whether waiver requires intentional act or whether inconsistency between the conduct and the maintenance of confidentiality is the governing test.

Holding

The High Court held that legal professional privilege had been waived in respect of the disclosed advice, but not over all related documents. Waiver occurs where the conduct of the privilege-holder is inconsistent with the maintenance of the confidentiality that privilege is designed to protect.

Ratio decidendi

Legal professional privilege is waived where the privilege-holder acts in a manner that is inconsistent with the maintenance of the confidentiality which the privilege exists to protect; it is not necessary to establish an intentional relinquishment of the privilege, and the test is objective inconsistency between the conduct and the confidentiality.

Obiter dicta

The majority observed that the common law doctrine of implied waiver is not confined to cases of fairness or to situations where the privileged material is used as a weapon; rather, the inconsistency principle is of general application and reflects the purpose underlying the privilege itself. The court also noted that waiver of part of a communication does not automatically waive privilege over all related communications unless fairness so requires.

Significance

Mann v Carnell is the leading Australian authority on implied waiver of legal professional privilege, establishing that the test is objective inconsistency between the privilege-holder's conduct and the confidentiality the privilege protects, a principle routinely applied in subsequent litigation and statutory contexts across Australian jurisdictions.

Key authorities

• Wardley Australia Ltd v Western Australia Wardley Australia Ltd v Western Australia (1992) 175 CLR 514cited
• Attorney-General (NT) v Kearney Attorney-General (NT) v Kearney (1985) 158 CLR 500considered
• Baker v Campbell Baker v Campbell (1983) 153 CLR 52considered
• Benecke v National Australia Bank Benecke v National Australia Bank (1993) 35 NSWLR 106considered
• General Accident Fire and Life Assurance Corporation Ltd v Tanter General Accident Fire and Life Assurance Corporation Ltd v Tanter [1984] 1 WLR 100considered
• Thomason v Campbelltown Municipal Council Thomason v Campbelltown Municipal Council (1939) 39 SR (NSW) 347cited