If a pebble is dropped into a pool of water, ripples will spread on the surface of the water; how far the ripples will spread and with what strength depends on a variety of factors, but there will always be a ripple of some kind. The same is true of a decision of a court of law. Notwithstanding what Professor Chayes has accurately described as the “bipolar” character of traditional civil litigation, it is almost inconceivable that the outcome of a civil action will affect no one but the parties to it: unless an exception can be found to John Donne's famous axiom that "No man is an Island, entire of itself”—and such a man, if he exists, is unlikely to bring an action in the first place—the ripple effect even of, say, a simple decision that an individual defendant must pay a sum of money by way of damages to an individual plaintiff will extend to their respective families and beyond. It is not wholly absurd to say of such a case that, for example, the retail traders, the banks, and so on with whom the parties have dealt or may deal in the future have an “interest” which an action by an injured individual may “protect” and, if they do, that interest is certainly "diffuse" and "fragmented" even if it is not “collective.”

In recent years, one of the most vibrant doctrines has been that of equitable estoppel. This doctrine is generally seen as having two main branches: the defensive doctrine of promissory estoppell and the older and more aggressive doctrine of proprietary estoppel, which can itself be used to obtain rights: to be the cause of action itself. The aim of this article is to analyse the central concepts of equitable estoppel in order to distinguish it from its common law counterpart, to consider its relationship to the law of contract and also to present the two main branches as being closely related concepts, based on common underlying themes.

To Speak of the European Court as an international tribunal is to expose oneself to the charge of heresy. No principle of Community law is more fundamental, none more frequently reiterated by the European Court, than that the Treaty establishing the European Economic Community “is more than an agreement which merely creates mutual obligations between the contracting States” but rather constitutes a new legal order capable of conferring rights and imposing obligations directly upon individuals. In the Court's words, “By contrast with ordinary international treaties, the E.E.C. Treaty has created its own legal system, which, on the entry into force of the Treaty, became an integral part of the legal systems of the Member States.” For this reason, Professor Lipstein has, with justification, said of Community law that it represents a “peculiar phenomenon … which does not fit into any regular pattern of international law.”Professor Hay has insisted upon describing it as “supranational law” and Professors Brown and Jacobs maintain that the function of the European Court, in interpreting and applying that law, is "constitutional" rather than international.