estoppel

Estoppel is a judicial device whereby a court may prevent or "estop" a person from making assertions or from going back on their word. The person barred from doing so is said to be "estopped". Estoppel may prevent someone from bringing a particular claim. In common law legal systems, the legal doctrine of estoppel is based in both common law and equity. Promissory and proprietary estoppel are specific forms of estoppel reflecting distinct legal traditions within various jurisdictions. Estoppel is also a concept in international law.

==Types of estoppel== There are many different types of estoppel, but the common thread between them is that a person is restrained from asserting a particular position in law where it would be inequitable to do so. By way of illustration: If a landlord promises a tenant that he will not exercise his right to terminate a lease, and relying upon that promise the tenant spends money improving the premises, the doctrine of promissory estoppel may prevent the landlord from exercising a right to terminate, even though his promise might not otherwise have been legally binding as a contract. The landlord is precluded from asserting a specific right. If a person brings legal proceedings in one country claiming that he was injured by a second person negligently, and the courts of that country determine that there was no negligence, then under the doctrine of issue estoppel the first person cannot normally argue before the courts of another country that the second person was negligent (whether in respect of the same claim or a related claim). The first person is precluded from asserting a specific claim.