Priestley v Priestley

The appeal in *Priestley v Priestley* concerned a dispute between the appellant and the respondent regarding the deceased's estate. The appellant alleged that the deceased had made a testamentary contract not to revoke her will, and alternatively, that the deceased was estopped from revoking her will due to the appellant's detrimental reliance on a mistaken belief that he would inherit certain property. The case was heard in the Court of Appeal of New South Wales.

The primary legal issues before the Court of Appeal were whether the conduct of the appellant and the deceased objectively demonstrated an intention to create a legally binding testamentary contract, and whether the deceased was contractually obliged not to revoke her will. Additionally, the court was required to determine if the doctrine of proprietary estoppel applied, specifically whether the appellant had relied to his detriment on a mistaken belief that he would inherit the deceased's property, and if it would be unconscionable for the deceased to have accepted the benefit of the appellant's assistance while aware of this mistaken belief. The court also considered whether the appellant needed to demonstrate that he would have acted differently but for his mistaken belief, and whether his reliance was unreasonable, as well as the proportionality of granting proprietary relief in light of the detriment suffered.

The Court of Appeal allowed the appeal, setting aside the orders made by the primary judge. The court found that the elements of proprietary estoppel were made out, concluding that it was unconscionable for the deceased to have accepted the benefit of the appellant's assistance when she knew of his mistaken belief that he would inherit the property. The court determined that the appellant's reliance on this mistaken belief was reasonable and that the detriment suffered was substantial, outweighing any potential detriment to the estate. Consequently, the court found that the deceased was estopped from denying the appellant's entitlement to the property.

The Court of Appeal ordered that the appeal be allowed, the orders of the primary judge be set aside, and that the parties file written submissions regarding costs. The parties were also directed to provide short minutes of order giving effect to the court's reasons.