Estoppel, constructive trusts and unconscionability

This article considers the extent to which there has been an assimilation of constructive trust and proprietary estoppel doctrines in the context of equitable claims to the family home. It is argued that, despite common characteristics, amalgamation of the two concepts into a unified concept of unconscionability is far from complete. The subject continues to be debated with vigour by the judiciary and trust lawyers. Here Professor Pawlowski maintains that the two doctrines remain separate and distinct. It has been argued strongly by Professor Hayton that any distinction between proprietary estoppel and constructive trusts is ‘illusory’ and that the basic principle of unconscionability underlies both concepts: see, Hayton, [1990] Conv. 370, at 380. In his view, the criterion for equity's intervention in both cases is unconscionable conduct on the part of the legal owner. This criterion, he suggests, should regulate both when and how the court intervenes in a given case. The remedy is at the court's discretion and should be only what is necessary to remedy the legal owner's unconscionable conduct. Moreover, it should be prospective so as not to bind a third party unless his conscience is also affected. Thus, according to Hayton, the underlying rationale of estoppel and constructive trust claims is ‘the discretionary prevention of unconscionable conduct’: ibid, at 380.