In Redfern Limited v O'Mahony [2009] IESC 18, Finnegan J held that there is no general principle whereby legal professional privilege in documents is waived by putting in issue allegations to which the privileged documents are relevant.

The appellants appealed to the Supreme Court against two orders of the High Court; firstly, an order refusing the appellants' application to inspect an opinion of senior counsel, and secondly an order allowing the respondents inspection of all privileged documents discovered by the appellants. The Supreme Court considered whether privilege was waived by the respondents in respect of the Opinion of senior counsel, as a result of the respondents furnishing a copy of it to two people. Additionally, the Supreme Court considered whether privilege was waived by the appellants, in respect of documents containing legal advice, on the basis that in their defence plea the appellants put in issue their state of mind and intended to rely at the hearing of the action on the fact that legal advice was obtained in entering into a contractual agreement.

Finnegan J. at the Supreme Court held firstly, that it is well established that privilege may be waived expressly or by implication. He stated that if a document comes into the public domain privilege will be lost. However it will not be lost where there is limited disclosure for a particular purpose or to parties with a common interest. The Supreme Court held that the disclosures in question were limited disclosures to third parties with a common interest and did not amount to an implied waiver. Accordingly the Supreme Court affirmed the order of the High Court, refusing the appellants' motion for inspection of the Opinion of senior counsel.

In regard to the second issue, it was held that privilege is not waived by putting in issue allegations to which the privileged documents are relevant. The Supreme Court therefore allowed the appellant's appeal in this respect and set aside the order of the High Court which granted the respondents inspection of all privileged documents discovered by the appellants.

Finnegan J found that two of the propositions derived from Australian authorities, and relied on by the respondent, did not represent good law in Ireland. He refused to follow the principle in Hong Kong Bank of Australia Limited v Murphy [1932] 2 V.R. 419, that privilege may be lost where the court might be misled if a document is not available; and also the principle in the case of Wardrope v Dunne [1996] 1 Qd. R. 224, that where in his pleadings a party relies on a state of mind, it would be unfair to permit that party to maintain privilege in respect of communications passing between them and their legal advisers which might bear upon the existence of that state of mind. In regard a third proposition, derived from Australian authority, that a party by pleading the privileged document into relevance waives legal professional privilege, the judge stated that such waiver will only arise, where the contents and effect of the legal advice are disclosed. That was not the position here as the appellant had informed the court that only the fact that legal advice was obtained would be relied upon.

Finnegan J stated that the law in Ireland is that as set out in the English cases of Paragon Finance Plc v Freshfields [1999] 1 WLR 1183 and Farm Assist Limited (In Liquidation) v Secretary of State for Environment, Food and Rural Affairs [2008] All ER 124. Those cases clarified that there is no general proposition that unfairness to an opponent will result in implied waiver of privilege. Nor is there any general implied waiver of privileged material merely because a state of mind or certain actions are in issue.

Comment: The Supreme Court judgment confirms that the test in Ireland for implied waiver of privilege follows the UK and is not based on general principles of fairness or on relevance. The judgment also confirms that implied waiver of privilege on the basis of unfairness is limited to proceedings instituted by a client against his solicitor. The only other area in which privilege can be lost on the basis of unfairness is in relation to partial disclosure of legal advice. Finnegan J stated that "where a party deploys in court material which would otherwise be privileged the other party and the court must have an opportunity of satisfying themselves that what the party has chosen to release from privilege represents the whole of the material relevant to the issue in question".