Despite the fact that the “nature, role and form” of financial market regulation has varied—sometimes significantly—from jurisdiction to jurisdiction, traditionally there has been a remarkable degree of unanimity about the need for comprehensive regulatory controls governing the operations of financial institutions and the financial markets more generally. In essence, this consensus derives from a conception of financial markets as being sufficiently distinct from other kinds of economic activity, such as manufacturing electrical goods, or the marketing of adventure holidays, to require extensive regulation and oversight. From a descriptive point of view, the inspiration for much of this regulation—at least in its statutory form—can very often be traced to various reactions to financial crises. In the US, for example, extensive Federal Securities legislation, which has been in place since the 1930s, was Congress’s response to bank runs and alleged financial abuses in the depression era.

This article focuses on a particular aspect of the operation of proprietary estoppel: it asks when a proprietary estoppel claim will give rise to a property right. The inquiry proceeds on the linked assumptions that proprietary estoppel is a means of acquiring rights and that rights thereby arising take effect immediately, without the need for any court order. Like any other means of acquiring rights, proprietary estoppel can give rise either to personal rights or to property rights: in some cases the estoppel claimant is acknowledged to have a personal right (e.g. to damages or a licence to use land); in others a property right (e.g. a lien; an easement; a lease; or a freehold). The central argument of this article is that proprietary estoppel should give rise to a property right only if that is necessary to protect the claimant’s reasonable reliance. Where a personal right gives sufficient protection that will have to do, whatever the claimant may have been promised or expected; this may well mean that the circumstances in which a property right arises are more narrow than has been thought.

John Austin, having spent the winter term of 1827/28 in the idyllic and peaceful Rhenanian university town of Bonn, far away from the bustle of London and the irritating failures he had suffered at the chancery bar, was unrivalled in his admiration for the modern version of Roman law as it had been interpreted, refined and further developed by the German scholars of his time. It was, he exclaimed, “greatly and palpably superior, considered as a whole, to the law of England. Turning from the study of the English to the study of the Roman law, you escape from the empire of chaos and darkness, to a world that seems by comparison, the region of order and light”. How he longed to be as acknowledged and as influential as one of the great expositors of that law. “I was born out of time and place”, he is reported to have lamented, “I ought to have been a schoolman of the twelfth century—or a German professor”. His desire was rather understandable, given that the nineteenth century English law professors regarded themselves as “a feeble folk.