Restitution – Unjust enrichment – Failure of basis or condition – Interest – Where client engaged law firm under retainer agreements – Where retainer agreements imposed binding obligations on client to pay legal costs – Where law firm had no right to retain payment under Legal Practice Act 2003 (WA) if, and to extent that, payment was found on taxation to exceed amount authorised by certificate from taxing officer – Where, prior to taxation, client and law firm reached settlement – Where settlement deed required repayment of sum as "amount that would have been ordered to be refunded" if there had been taxation – Where settlement deed left open option of litigating further claim for interest on settlement sum – Whether interest available on settlement sum – Whether there had been failure of basis or condition for client's payments of invoices issued under retainer agreements – Whether Legal Practice Act formed comprehensive regime for recovery of principal sum paid for legal costs over amount certified by taxing officer, and interest on that sum, to the exclusion of any common law restitutionary claim.
Words and phrases – "basis or condition", "bill of costs", "compound interest", "condition subsequent", "conditional obligation", "deemed taxation", "failure of basis or condition", "fair and reasonable", "interest", "legal costs", "no juristic reason", "no justification", "principal", "restitution", "retainer agreement", "simple interest", "statutory interest", "taxation certificate", "unjust enrichment".
Legal Practice Act 2003 (WA), ss 221, 222, 229(a), 231, 232, 235, 240, 242, 243.
Legal Profession Act 2008 (WA), ss 2(b), 598, 616(1).
Legal Profession Uniform Law Application Act 2022 (WA), s 260.
Supreme Court Act 1935 (WA), s 32.