Estoppel is a legal doctrine recognised both at common law and in equity in various forms. It is meant to complement the requirement of consideration in contract law. In general it protects a party who would suffer detriment if: The defendant has done or said something to induce an expectation The plaintiff relied (reasonably) on the expectation... ...and would suffer detriment if that expectation were false. Unconscionability by the defendant has been accepted as another element by courts, i… (More on Estoppel)