4. Consideration and estoppel
Without assuming prior legal knowledge, books in the Directions series introduce and guide readers through key points of law and legal debate. Questions, diagrams and exercises help readers to engage fully with each subject and check their understanding as they progress. This chapter explains the nature of consideration with the aid of examples and discusses two basic definitions of consideration (consideration as a legal benefit or burden and as the price of a promise) as well as the past consideration rule. It addresses whether performance of an existing duty can count as a legal benefit or burden to form consideration for a promise. It considers existing public duties, existing duties owed to a third party and existing duties owed to the promisor. The chapter examines the related rules concerning part payment of a debt and the extent to which promises not supported by consideration can be enforced using promissory estoppel.