The principal purpose of this article is to consider how well, or badly, the English system of land law and conveyancing handles the exceptional, but nonetheless important, cases of informal transactions in land. The article is in six parts. Part 1 points to the high degree of formality normally required for transactions in land and discusses the exceptional cases where informal transactions are permitted. Some criticisms and suggestions for reform are made. One of the exceptional cases where interests in land can arise informally is under the doctrine of proprietary estoppel, and part 2 considers whether interests so arising can be fitted satisfactorily into a conveyancing system which increasingly, because of the spread of the title registration system, requires interests in land to be registered in order to bind subsequent purchasers. The conclusion reached is that both the registered and the unregistered land systems cope satisfactorily with such interests. In part 3, attention is turned to a well-known but difficult case, ER Ives Investment Ltd v High,l which is treated in many of the books as a case on proprietary estoppel. The Court of Appeal had great difficulty in deciding the case on its merits without doing violence to the registration requirement. It is argued that none of the judgments gives a satisfactory explanation, but that using a different form of estoppel, a better explanation is possible which is consistent with both the registered and unregistered land systems. In part 4 it is argued that Ives v High is but one example of a wider category of cases where the courts show themselves to be unhappy with the proposition that an unregistered interest can be defeated by a purchaser who has actual knowledge of that interest. This point is illustrated in part S by a brief examination of the Green family saga,2 and it is argued that the principal decision in favour of Mrs Green causes concern. Part 6 concludes the article with an argument for abolishing the protection given to a purchaser with actual knowledge, and some other proposals for reform.