It has been said that ‘the law of limitation is a subject which peculiarly involves an enquiry into first principles.’ That is particularly true in registered land. Section 75 of the Land Registration Act 1925 grafted into registered land a concept inimical to it, namely the possibility of defeat by adverse possession of a flawless documentary title. That endeavour has on the whole been successful; but there remain problems, concerning such fundamental concepts as trusts, the nature of legal estates after 1925, and ‘title absolute.’ This article seeks to explore those problems; at the same time, the opportunity will be taken to look again at the decision in Spectrum Investment Co v Holmes and to suggest that it need no longer be regarded as a major source of difficulty.

The current distinctions between different forms of estoppel are inappropriate and traditional orthodoxy is being challenged by judges and by academics. It is now necessary to recognise that the organising concept for the doctrine of estoppel is unconscionability because the function of estoppel is to restrain injustice arising from unconscionable conduct. The form ofestoppel, known as promissory estoppel, and stemming from the decision in Central London Property Ltd u High Trees House Ltd, is not triggered by the organising concept of unconscionability. It should be regarded, therefore, as an exceptional contractual response, in various situations, to the requirement of consideration. It follows that, in principle, estoppel based upon the concept of unconscionability, may be employed as an independent cause of action. There is ample evidence that this already happens in the context of claims concerning land. This article seeks to demonstrate that estoppel can and should be treated as an independent cause of action in a more general context.

This article is an attempt to add to our understanding of the map of common law obligations. That there is such a thing is an article of faith among those who believe that the common law is based on reason. Any map does three things: it represents a certain area; it enables us to locate any point on that area by providing us with axes of reference (for example, longitude and latitude) and it identifies certain points on that area as significant. The map of common law obligations covers the set of all possible duties. A duty is located in that set by reference to its pattern (its content) together with its origin (the set offacts sufficient to give rise to that duty). The map of common law obligations identifies all the duties which the common law may give effect to by compelling those who are subject to those duties to comply with them.

From within the law school, group personal injury litigation may be approached in various ways. Until very recently it was, indeed, ignored as an irrelevant foreign development: not perhaps ‘it could never happen here’, but at least ‘it hasn’t happened here, yet’. Now that it plainly has happened, it is nonetheless possible to ignore it. The question whether the snail in my ginger beer bottle can give rise to an action is not, in principle, affected by what other people found when they opened theirs; if it is said that in practice it cannot but be affected, the retort would be that the law schools need not concern themselves with the sort of practicalities involved. Indeed, group litigation barely rates a mention in most practitioners’ texts either; so many academics feel excused from considering it all, even as a mere footnote to the general run of cases.

In what circumstances, if any, can a person be held liable in tort for failing to prevent another person from causing harm?

Different legal systems answer the question in different ways. In many US jurisdictions, for example, although theoretically there is a presumption against liability, a great number of categories of citizen (including doctors, bar-keepers and psychologists) are held responsible for the harm caused by others to whom, for example, they have prescribed medicines or served alcoholic drinks or offered advice.

Theoretical discussion of the question of whether and under what circumstances ignorance of law should be a defence from criminal liability has had a peculiar history in Anglo-American law. Commentators have been more convinced that ignorance oflaw should generally not serve as a defence than they have been persuaded by any particular rationale in favor of this rule. When one argument is shown to be unsound, another emerges to take its place, preserving the conclusion intact; the weight of scholarly opinion does not shift to embrace the position that ignorance of law should typically be a defence from criminal liability.