The ACT Court of Appeal (majority McCallum CJ and Taylor J, Collier J dissenting) held that where a payment is made by mistake to a party not entitled to it, the payer need not independently prove 'unjustness' beyond the causative mistake; proof that the payment was made and was caused by the mistake establishes enrichment at the payer's expense, following David Securities. The Court further held that a finding of ostensible authority estopping one party (Benex) from denying an agent's authority does not operate to benefit a different party (Civil) in a separate restitution claim — the estoppel constrains only the party who made the representation and does not convert the represented state of affairs into fact. Collier J would have allowed the appeal on the basis that Nova's payment to Civil discharged Nova's contractual liability to Benex via ostensible authority, precluding the restitution claim.
The full text is available to signed-in members.