There are a number of situations where it is possible to say that a person may, and in some cases almost certainly will, get an interest in property at some time in the future. However, until that time there is some degree of uncertainty: there is usually some risk that no interest will be acquired and there may be uncertainty as to the identity of the property or the nature of the interest. This article deals with the interim period between the act or event that initiates the interest and its final acquisition. It considers the approaches taken by the courts to the question of what rights, if any, come into existence during that interim period and whether there is a distinct entity or interest that can be described as a “floating right”.

The conflict between common law and equity on the question of when time should be regarded as being “of the essence” for the performance of a contract has often been debated, as has the impact of its resolution by the Judicature reforms in favour of equity's more relaxed approach. Even so, it is tolerably clear that the two approaches have been substantially assimilated within general principles of discharge for breach. If, as a matter of construction, a time stipulation is a condition, then time is of the essence. Alternatively, time may have become of the essence by an effective notice to perform served by a promisee. If the contract has been validly discharged on either basis, specific performance will not be ordered in favour of the promisor.1

The prospective buyers of a waste treatment plant (“Reprotech”) wished to use the site to generate electricity from the waste produced. They asked the Chief Planning Officer of the local council whether this would be a material change of use, for which planning permission would be required, and were assured that it would not. After they bought the land, the council insisted that the Officer lacked authority to make such a determination and required a formal application for planning permission; this was met by local opposition. Must the buyers make such an application and suffer a reduction in the value of the land if the application is unsuccessful, or should the public bear the consequences of the unauthorised act of the Officer? This was one of the questions facing the House of Lords in R. v. East Sussex County Council, ex p. Reprotech (Pebsham) Ltd. [2002] UKHL 8, [2002] 4 All E.R. 58. Their Lordships denied that there had been a “determination” for the purposes of the Town and Country Planning Act 1990, s. 64, upon which Reprotech sought to rely, but the obiter discussion of the proper role of estoppel in public law is the focus of this note.

It was perhaps never very likely that the proponents of fundamental breach would allow their doctrine to die just because of some obiter dicta on the subject from the House of Lords. In that respect, therefore, the recent decision of the Court of Appeal in Harbutt's “Plasticine” Ltd. v. Wayne Tank and Pump Co. Ltd. need cause no surprise. What had happened in that case, essentially, was that the defendants had agreed to manufacture some equipment and to instal it in the plaintiffs' factory under a contract, clause 15 of which limited the defendants' liability to the amount of the contract price (£2, 330). A small and easily corrected defect in the equipment caused a fire which destroyed the factory and resulted in a loss to the plaintiffs of some £150,000. The Court of Appeal held (Lord Denning M.R. dubitante) that on its true construction clause 15 covered the loss in the events which had occurred. The whole court nevertheless joined in holding that the destruction of the factory and consequent discharge by breach of the contract had the effect of making clause 15 inapplicable. Judgment was given for the full amount of the loss.

The word “practice” does not occur frequently in the pages of H. L. A. Hart's book The Concept of Law. Yet the notion of a practice is, if not the key to the science of jurisprudence, at least the key to the central foundations of Hart's theory. The validity of a law, according to Hart, can be established by reference to certain social (or official) practices: in this way questions of legal validity are separated from questions of moral justification. The theory can profitably be read as a study of the connection between the characteristic forms of legal discourse and the existence of social practices.

It is surprising that the already voluminous literature on the Hart v. Dworkin dispute has neglected the issues I intend to raise. One of Dworkin's arguments attacks Hart's claim that the existence of a rule is, in some cases, the existence of a social practice. The argument, if successful, would refute everything Hart has to say about the rule of recognition. Can Hart's theory meet this criticism? I shall sketch the hint of a shadow of an analysis of practices which offers Hart an escape, but an escape which has its price. By adopting something resembling my analysis, Hart can preserve major elements of his theory. I will attempt to isolate those features which are valuable and which can be salvaged. The price that Hart must pay, however, is the abandonment of his extreme positivism. If my suggestions about practices are correct, then the ultimate questions concerning legal validity are moral or political questions.

Twenty years ago Mr. Cairns set himself the task of looking at law from three points of view, that of the social sciences, that of logic and the empirical sciences, and that of philosophy. Law and the Social Sciences was published in 1935, the Theory of Legal Science in 1941. The volume under review completes the trilogy. The object of all these volumes is the same—‘To construct the foundation of a theory of law which is the necessary antecedeat of a possible jurisprudence’. All those who have come under the spell of Mr. Cairns' stimulating thought will look forward with the greatest interest to the application and expansion of his conclusions which is now promised us in a projected final work, The Elements of Legal Theory.