Introduction
The doctrine of consideration is a cornerstone of English contract law, serving as the primary test of enforceability for promises. However, its strict application can sometimes lead to outcomes that appear unjust. In response, the equitable doctrine of promissory estoppel was developed to provide a degree of flexibility, preventing a party from going back on a promise where it would be unconscionable to do so. This essay will critically discuss the statement that promissory estoppel was developed to mitigate the rigidity of consideration, yet its scope remains uncertain and limited. It will argue that while promissory estoppel serves an important function in preventing injustice in specific circumstances, its development has been cautious, and its scope is deliberately constrained by the courts, ensuring it does not completely undermine the traditional role of consideration.
The Doctrine of Consideration
What is Consideration and Where is it Found?
In the law of contract in England and Wales, consideration is an essential element required for the formation of a legally binding simple contract. A promise is generally not enforceable unless it is supported by consideration or made in a special form, such as a deed. Consideration is often described as the 'price of the promise' – something of value in the eyes of the law must be given in exchange for another's promise (McKendrick, 2021). It is the mechanism by which courts decide which promises should be enforced by law and which should be treated as gratuitous, and therefore non-binding.
Definitions of Consideration
The classic definition of consideration was provided by Lush J in Currie v Misa (1875), where it was described as:
> "A valuable consideration, in the sense of the law, may consist either in some right, interest, profit, or benefit accruing to the one party, or some forbearance, detriment, loss, or responsibility, given, suffered, or undertaken by the other…" (Currie v Misa (1875) LR 10 Ex 153, p. 162).
This definition highlights the concept of a bargain, involving either a benefit to the person making the promise (the promisor) or a detriment to the person to whom the promise is made (the promisee). A more modern interpretation, focusing on the idea of exchange, was endorsed by the House of Lords in Dunlop Pneumatic Tyre Co Ltd v Selfridge & Co Ltd [1915] AC 847, which approved Sir Frederick Pollock's definition: "An act or forbearance of one party, or the promise thereof, is the price for which the promise of the other is bought, and the promise thus given for value is enforceable."
The Function of Consideration
The requirement of consideration serves several important functions. Firstly, it acts as a key indicator that the parties intended their agreement to be legally binding. By demanding a reciprocal exchange, the law filters out informal, social, or gratuitous promises that are not intended to create legal relations. Secondly, it serves a cautionary function, encouraging parties to think carefully before entering into a binding agreement. Finally, it provides a simple test of enforceability for the courts. However, the rules surrounding consideration can be rigid. For instance, the rule that performing an existing duty does not amount to good consideration (Stilk v Myrick (1809)), and the rule that part-payment of a debt cannot discharge the whole debt (Foakes v Beer (1884)), can lead to harsh results where one party has relied on a promise to vary an existing contract.
The Nature and Purpose of Promissory Estoppel
It is in the context of this rigidity that the equitable doctrine of promissory estoppel emerged. Equity is a body of law that intervenes where the strict application of common law rules would lead to an unconscionable outcome. Promissory estoppel is a prime example of this intervention. Its central purpose is to prevent a person from reneging on a promise where another person has relied on that promise to their detriment.
The modern doctrine is largely attributed to the judgment of Lord Denning in Central London Property Trust Ltd v High Trees House Ltd [1947] KB 130. In this case, a landlord promised to accept a reduced rent during the Second World War. When the war ended, the landlord sought to claim the full rent for the entire period. Lord Denning held that the landlord could resume their right to full rent for the future but would have been estopped from claiming the arrears that had accrued during the war. He reasoned that a promise intended to be binding, intended to be acted on, and in fact acted on, is binding so far as its terms properly apply. This principle provides a means of making a promise to vary an existing contract binding, even without new consideration.
The Core Elements and Limitations of Estoppel
Core Elements of Promissory Estoppel
For promissory estoppel to be successfully invoked, several conditions must be met:
- A Pre-existing Legal Relationship: The doctrine typically operates to modify existing legal relationships, rather than to create new ones. It is most commonly applied to contractual relationships.
- A Clear and Unambiguous Promise: There must be a clear and unequivocal promise or representation by the promisor that they will not insist on their strict legal rights (Woodhouse A.C. Israel Cocoa Ltd S.A. v Nigerian Produce Marketing Co. Ltd [1972]).
- Reliance: The promisee must have acted in reliance on the promise. This means they must have altered their position in some way. While it is debated whether this reliance must be detrimental, it is clear that it must be inequitable for the promisor to go back on their word (Chen-Wishart, 2018).
- Inequitable to Resile: It must be unfair or unconscionable for the promisor to go back on their promise. This is the core of the doctrine and gives the court discretion. For example, in D & C Builders v Rees [1966], a creditor’s promise to accept less was not binding because it was extracted through intimidation, meaning it was not inequitable for them to demand the full amount later.
Key Limitations of the Doctrine
Despite its utility, the scope of promissory estoppel is significantly limited, which supports the assertion in the question.
The first and most significant limitation is that promissory estoppel can only be used as ‘a shield and not a sword’. This means it can be used as a defence to prevent a promisor from enforcing their strict legal rights, but it cannot be used to create a new cause of action where none existed before. This principle was confirmed in Combe v Combe [1951], where a wife’s attempt to use her ex-husband’s promise to pay her maintenance as a basis for a claim failed because estoppel does not create a cause of action. This restriction ensures that estoppel does not completely supplant consideration as the basis for contract formation. This approach contrasts with that taken in other jurisdictions, such as Australia, where the courts in Waltons Stores (Interstate) Ltd v Maher (1988) have allowed estoppel to be used as a sword to create enforceable rights.
A second limitation is that the doctrine is generally considered to have a suspensory effect on legal rights, rather than an extinctive one. In many cases, it simply suspends the promisor’s rights, which can be revived upon giving reasonable notice (Tool Metal Manufacturing Co Ltd v Tungsten Electric Co Ltd [1955]). This creates uncertainty. For instance, in High Trees, the right to full rent was revived once the conditions giving rise to the promise (the war) had ceased. However, in circumstances where the promisee cannot be returned to their original position, the estoppel may have the effect of extinguishing the right permanently. The ambiguity between whether rights are suspended or extinguished contributes to the doctrine's uncertain scope.
The Role of Equity and Fairness
At its heart, promissory estoppel is an equitable remedy concerned with justice and fairness. The requirement that it must be 'inequitable' for the promisor to go back on their promise is paramount. This allows courts to examine the conduct of the parties and the context of the promise. The decision in D & C Builders v Rees illustrates this perfectly. Mrs Rees had not acted equitably by taking advantage of the builders' financial difficulties, and therefore she could not rely on the equitable doctrine of estoppel to enforce their promise to accept less. This ensures that the doctrine is only used to protect those who have acted in good faith and not as a tool for promisors to escape their obligations unfairly.
Critical Evaluation and Conclusion
In conclusion, the statement that promissory estoppel was developed to mitigate the rigidity of consideration, yet its scope remains uncertain and limited, is an accurate reflection of its status in English law. The doctrine undoubtedly serves as a valuable corrective to the sometimes-harsh application of the common law requirement for consideration, particularly in the context of modifying existing contracts. It prevents unconscionable behaviour and provides protection for a party who has relied on a promise.
However, its development has been cautious. The courts have deliberately limited its scope to prevent the wholesale abolition of the doctrine of consideration. The fundamental limitation that it is a 'shield, not a sword' means it cannot be used to enforce gratuitous promises and create new legal rights. Furthermore, the uncertainty as to whether it suspends or extinguishes rights means that parties cannot always be sure of their legal position. Promissory estoppel, therefore, exists in a delicate balance with consideration. It softens the sharpest edges of the common law but does not, and is not intended to, replace it. It remains an important but circumscribed equitable doctrine, whose very limitations and uncertainties are a product of the judicial desire to maintain the primacy of consideration in the English law of contract.
References
- Chen-Wishart, M. (2018) Contract Law. 6th edn. Oxford University Press.
- McKendrick, E. (2021) Contract Law: Text, Cases, and Materials. 10th edn. Oxford University Press.
Case Law
- Central London Property Trust Ltd v High Trees House Ltd [1947] KB 130
- Combe v Combe [1951] 2 KB 215
- Currie v Misa (1875) LR 10 Ex 153
- D & C Builders v Rees [1966] 2 QB 617
- Dunlop Pneumatic Tyre Co Ltd v Selfridge & Co Ltd [1915] AC 847
- Foakes v Beer (1884) 9 App Cas 605
- Stilk v Myrick (1809) 2 Camp 317
- Tool Metal Manufacturing Co Ltd v Tungsten Electric Co Ltd [1955] 1 WLR 761
- Waltons Stores (Interstate) Ltd v Maher (1988) 164 CLR 387
- Woodhouse A.C. Israel Cocoa Ltd S.A. v Nigerian Produce Marketing Co. Ltd [1972] AC 741
