Painting Proprietary Estoppel

In 1982, while a lecturer at Essex University, Mark Thompson wrote what came to be regarded as a signpost article about the development of proprietary estoppel. In From Representation to Expectation: Estoppel as a Cause of Action,1Mark traced the development of estoppel from its origins as a rule of evidence, which he characterised as common law estoppel2 to its acceptance as an equitable cause of action.3 He recognised, of course, that proprietary estoppel was an ancient doctrine, but concluded that Taylors Fashions Ltd v Liverpool Victoria Trustees Co Ltd4 had unshackled it by identifying the “underlying principle” of unconscionability.5 He concluded that equitable estoppel was the medium through which non-contractual expectations could be fulfilled, in whole or in part. Critically, however, while Mark was arguing for a “flexible and wide ranging doctrine”,6 he did not see it as an attack on orthodox contract law,7 or as the embodiment of a free-form judicial discretion to achieve “fairness”. Proprietary estoppel was the manifestation of a principled doctrine leading to the fulfilment of expectations, unconscionably denied.8