The relationship that exists between the parties to a contract. The common law doctrine of privity of contract established that only the parties to the contract, i.e. those that provided consideration, could sue or be sued under the contract. Third parties could not derive rights from, nor have obligations imposed on them by, someone else's contract. This position has now been modified by the Contracts (Rights of Third Parties) Act 1999. By the provisions of the Act, a person or class of persons can enforce a term of a contract to which he is not a party provided that the term purports to confer a benefit on him or the contract expressly provides for such enforcement. The Act does not, however, interfere with the principle that a person cannot incur obligations under a contract to which he has not provided consideration.