The doctrine of promissory estoppel, a principle rooted in equity and fairness, serves as an essential bulwark against inequitable conduct, particularly when one party has acted upon the promise or assurance of another to their detriment. Originally developed in common law jurisdictions, the doctrine has since found robust applicability within Indian jurisprudence, albeit with nuanced modifications. This legal doctrine seeks to bind a promisor who, despite the lack of consideration, has made a representation or promise that another party has relied upon. This article seeks to provide a comprehensive analysis of the doctrine, its historical evolution, its application in Indian law, and its limitations, with references to relevant case laws, including landmark decisions of the Supreme Court of India.

Introduction
The doctrine of promissory estoppel is a critical principle within the jurisprudence of contract law. It operates as a mechanism to enforce promises that, while not supported by consideration, have been relied upon by a promisee to their detriment. Traditionally, in the domain of common law, a contract is rendered enforceable when it is supported by consideration. However, the strict application of this principle often led to inequitable outcomes, particularly where a party had relied on a promise but could not enforce it due to the absence of consideration.

Promissory estoppel, thus, evolved as an equitable exception to the rigidities of common law, providing relief where strict adherence to the rule of consideration would result in manifest injustice. In India, the doctrine has developed through judicial interpretation, primarily by the Supreme Court, which has consistently upheld the doctrine in various contexts, particularly in relation to governmental promises and assurances.

Evolution of the Doctrine of Promissory Estoppel

The genesis of the doctrine can be traced back to the 19th-century English case of Hughes v. Metropolitan Railway Co. [(1877) 2 App Cas 439], where Lord Cairns enunciated the principle that when one party to a transaction leads another to believe that strict rights will not be enforced, the former will be estopped from going back on the representation. However, it was in the case of Central London Property Trust Ltd v. High Trees House Ltd [(1947) KB 130] that Lord Denning significantly expanded the doctrine, laying the groundwork for its modern application.

In High Trees, the defendant had reduced the rent for the plaintiff during the Second World War, and the plaintiff had acted upon this promise. When the defendant sought to revert to the original rent after the war, the court held that although the promise lacked consideration, the defendant was estopped from going back on the promise since the plaintiff had relied upon it.

Application of the Doctrine in Indian Jurisprudence

In India, the doctrine of promissory estoppel was first recognized by the Supreme Court in Union of India v. Anglo Afghan Agencies [(1968) 2 SCR 366]. In this case, the government had issued an export promotion scheme, promising certain incentives to exporters. The court held that the government was estopped from going back on its promise, as the exporters had relied upon the assurance to their detriment. The court's observation that the doctrine is applicable even against the government provided a significant extension to its applicability.

Subsequently, in Motilal Padampat Sugar Mills Co. Ltd. V. State of Uttar Pradesh [(1979) 2 SCC 409], the Supreme Court reinforced the applicability of promissory estoppel, holding that the state was bound by its promise to exempt the appellant's factory from sales tax for a period, despite the absence of formal legislation to that effect. The court observed that it would be manifestly unjust and unfair for the government to renege on its promise, especially when the appellant had altered its position based on the said promise.

Essentials of the Doctrine

• Clear and Unequivocal Promise: There must be a clear and unequivocal representation or promise made by one party to another.
• Alteration of Position: The promisee must have acted upon the representation and altered their position to their detriment.
• Reliance: The promisee must demonstrate that they relied upon the promise in good faith.
• Injustice: It must be shown that the promisor would cause significant injustice or harm if allowed to renege on the promise.

Promissory Estoppel Against the Government

In India, promissory estoppel has often been invoked against the government and public authorities, particularly when they have made representations that induced individuals or corporations to act. In the case of Delhi Cloth and General Mills Ltd. V. Union of India [(1987) 4 SCC 342], the government was estopped from levying customs duty retrospectively after assuring the appellant of certain exemptions. The Supreme Court has reiterated that the doctrine applies against the government in the same manner as it applies to private parties, except where it can be demonstrated that the public interest necessitates a deviation from the promise.

However, in Jit Ram Shiv Kumar v. State of Haryana [(1981) 1 SCC 11], the court carved out an exception, holding that the doctrine cannot be invoked to compel the government to perform illegal acts or acts that are outside its statutory power. This limitation ensures that promissory estoppel is not used to perpetuate ultra vires promises.

Limitations of the Doctrine

While the doctrine of promissory estoppel operates to ensure fairness, it is not without limitations. The most significant limitation arises in cases where enforcing the promise would contravene statutory provisions or where the public interest would be adversely affected. In State of Rajasthan v. J.K. Udaipur Udyog Ltd. [(2004) 7 SCC 673], the Supreme Court held that promissory estoppel cannot be invoked if the enforcement of the promise would be against the law or public policy.

Another key limitation is that promissory estoppel cannot be used as a sword but only as a shield. This means that a party cannot use promissory estoppel to claim damages but can only use it to prevent the other party from going back on their promise.

Conclusion
The doctrine of promissory estoppel serves as a testament to the equitable underpinnings of contract law. It operates to mitigate the rigidities of common law, ensuring that justice prevails where a party has acted in reliance on a promise. In India, the judiciary has played a pivotal role in shaping and expanding the doctrine's contours, applying it even against the government, thereby holding public authorities accountable for their promises. Nevertheless, the doctrine is subject to limitations, particularly where enforcing the promise would contravene statutory provisions or the public interest.

In the ultimate analysis, the doctrine of promissory estoppel embodies the maxim "Equity will not suffer a wrong to be without a remedy" (ubi jus ibi remedium). It provides a safeguard against inequitable conduct, ensuring that parties are held to their promises when another has acted upon them to their detriment. Its continued relevance in modern jurisprudence is a reflection of the judiciary's commitment to fairness and equity in the realm of contractual relations.

References:

1. Union of India v. Anglo Afghan Agencies [(1968) 2 SCR 366]
2. Motilal Padampat Sugar Mills Co. Ltd. V. State of Uttar Pradesh [(1979) 2 SCC 409]
3. Central London Property Trust Ltd v. High Trees House Ltd [(1947) KB 130]
4. Delhi Cloth and General Mills Ltd. V. Union of India [(1987) 4 SCC 342]
5. State of Rajasthan v. J.K. Udaipur Udyog Ltd. [(2004) 7 SCC 673]