Mann v Carnell

The High Court of Australia considered the dispute between the appellant, Mr Mann, and the respondent, Ms Carnell, concerning the enforceability of a deed of settlement. The parties had entered into a deed to resolve a family dispute, but Mr Mann later sought to set aside the deed, alleging it was procured by undue influence and unconscionable conduct.

The central legal issues before the High Court were whether the deed of settlement was voidable on the grounds of undue influence or unconscionable conduct, and if so, what the consequences of setting aside the deed would be. Specifically, the court had to determine if Ms Carnell had exercised undue influence over Mr Mann, or if her conduct in procuring the deed was unconscionable, thereby vitiating Mr Mann's consent.

The High Court ultimately found that the primary judge had erred in concluding that the deed was voidable. Their Honours reasoned that the evidence did not establish the necessary elements for undue influence, particularly the absence of proof that Ms Carnell's will had been substituted for Mr Mann's. Furthermore, the court held that the conduct complained of did not amount to unconscionable dealing, as there was no exploitation of a special disadvantage by Ms Carnell. The principles applied focused on the high threshold required to prove undue influence and unconscionable conduct, requiring more than mere pressure or persuasion in the context of a settlement of family disputes.

The High Court allowed the appeal, setting aside the orders of the Full Court of the Supreme Court of the Australian Capital Territory and reinstating the orders of the primary judge, which had dismissed Mr Mann's claim to set aside the deed.