A collateral contract is one where the parties to one contract enter into or promise to enter into another contract. Thus, the two contracts are connected and it maybe enforced even though it forms no constructive part of the original contract. According to Lord Denning MR in the case of Evans & Sons Ltd v Andrea Merzario Ltd  1 WLR 1078 a collateral contract is ‘When a person gives a promise, or an assurance to another, intending that he should act on it by entering into a contract, we hold that it is binding’. Thus, no term of the collateral contract is found in the original one, but nevertheless it is enforceable for the original one. A collateral contract usually takes the form of a unilateral contract. A unilateral contract is where only one party to it makes a promise. This promise is usually in the form of doing something in return for something else. The offer and acceptance of the agreement is the original intention of the first contract that is in place. The consideration of the collateral contract is the promise to enter into the original agreement. Whereas in a three way agreement it can be used as a means to evade the notion of privity. A collateral contract was evidenced in the case of Shanklin Pier v Detel Products  2 KB 854. In this case the plaintiffs were owners of a pier and were promised by the paint manufacturers, who were the defendants, that their paint has a life span of seven years. This was said in the attempt to induce the plaintiff into buying the defendant’s paint. Due to this representation the plaintiff instructed the decorators to purchase the paint and use it to decorate the pier. This was duly done, however the paint only lasted three months. During the inception of the case the plaintiff’s did not appear to have a remedy as they had not provided the defendants with any consideration for the promise. The only contract in force was between the defendant and the decorators for the purchasing of the paint, this did not include the plaintiffs. However, it was held that the plaintiffs could recover damages on the basis of a collateral contract. It was held that the consideration for the promise as to the life of the paint was sufficiently inductive to render it effective in the chain of purchase. The contract in existence in this case was to purchase paint in order to re-decorate the pier. However, according to the case of Wells (Merstham) Ltd v Buckland Sand and Silica Co Ltd  2 QB 170, the construction of a collateral contract can be used even when there is not a contract specified at the time the promise was made. In this specific case the plaintiffs were chrysanthemum growers and bought sand from a third party that was produced by the defendants. This sand was purchased on the undertaking from the defendants over its iron oxide content. This undertaking proved to be incorrect and the plaintiffs sued on the basis of the loss suffered. It was held that they could claim damages, even though no main contract was in existence, due to the fact that one was in contemplation. Thus, a collateral contract is a creation of the courts to allow certain pre-contractual comments to be relied upon inn the event of a dispute. Conclusion
In conclusion, a collateral contract is one that is a second agreement that pertains to the original agreement. It is used to insert an intention that the goods bought by the claimants should reflect the pre-contractual statements made as to their durability and quality.
Collateral contract is a concept which has gradually evolved since its inception. However, collateral contract has been applied in a limited fashion in Australia, compared to other jurisdictions.
In this essay, I will argue that collateral contract has outlived it usefulness and currency in legal practice in Australia. To remain current, the broadening of its application is essential.
To support my argument, I will discuss: