Can You Enforce a Promise Without a Signed Contract?

The assumption that a handshake or a verbal assurance carries no legal weight is, in Victoria, demonstrably wrong. While a signed contract remains the clearest and safest evidence of a binding agreement, the law has long recognised that parties sometimes act in serious and costly reliance on promises that were never reduced to writing. Where one party encourages another to proceed on the basis of a representation, and that other party does so to their significant detriment, equity will not simply stand aside.

Understanding the twin doctrines of consideration and promissory estoppel is essential for anyone who negotiates, makes promises, or acts on the promises of others in a commercial or property context. Both doctrines operate in Victoria today with full force, and both have produced outcomes in the courts that would have surprised the parties who thought they were simply having a conversation.

The Role of Consideration

Consideration is the legal concept that distinguishes a binding contract from a gratuitous promise. Put plainly, a promise is only enforceable if the person receiving it has given something in return — whether that is money, a service, a forbearance from exercising a right, or a counter-promise. Without consideration, there is no contract; there is merely an expression of intent that the law will not compel anyone to honour.

Courts in Victoria do not inquire into whether the consideration exchanged was commercially equivalent to the promise it supported. A peppercorn, famously, will do. What the law requires is that consideration be real, that it move from the person seeking to enforce the promise, and that it exist in response to the promise — not as some prior act that preceded it.

This last point is frequently misunderstood. Past consideration — something already done before a promise was made — will not ordinarily support that promise. If a party performs a service and the other then says, gratefully, "I'll pay you for that," the subsequent promise may be unenforceable in the absence of a fresh agreement. The High Court has, however, recognised an important qualification: where a past act was performed at the request of the promisor, and the circumstances were such that both parties reasonably understood payment would follow, the subsequent promise to pay a specified amount will be treated as part of the same transaction and may be enforced.

When the Pre-Existing Duty Rule Creates Problems

A recurring issue in commercial contracts arises when a party promises additional payment to induce someone to perform obligations they are already contractually bound to fulfil. Under the traditional rule, performing a pre-existing contractual duty cannot constitute good consideration for a fresh promise of more money. The logic is straightforward: if you are already obliged to do something, you are giving nothing new in exchange for the additional promise.

Victorian courts, following the English Court of Appeal's reasoning in Williams v Roffey Bros, have recognised that this rule does not always produce commercially sensible outcomes. Where a promisor obtains a genuine practical benefit from the other party's continued performance — avoiding the expense of finding a replacement contractor, or avoiding penalties under a head contract — that practical benefit may constitute sufficient consideration for the promise of additional payment. The doctrine has been extended in Australia and applies to commercial negotiations in Victoria where the surrounding circumstances support it.

The limits of this principle matter equally. It does not permit a party who is already owed a debt to accept partial payment and then later sue for the balance simply because they changed their mind. The rule in Foakes v Beer — that payment of a lesser sum is not satisfaction of a greater debt without something more — remains good law in Victoria. A creditor who agrees to accept less than is owed has not surrendered the right to pursue the balance unless fresh consideration supports that agreement, or unless promissory estoppel intervenes.

Promissory Estoppel — Equity's Answer to Unconscionability

Promissory estoppel is the doctrine that prevents a party from resiling from a clear and unequivocal promise where the other party has acted in reliance on that promise to their detriment, and where it would be unconscionable to allow the promisor to go back on their word. It operates not as a cause of action in its own right under traditional analysis, but as a shield against unconscionable conduct — though Australian courts have, in significant decisions, extended its reach considerably.

The requirements are well established. The representation must be clear and unequivocal — a vague indication, a qualified statement, or an expression of hope will not suffice. The party relying on the representation must have acted on it in a manner that is referable to the representation itself. And the detriment suffered must be real: not merely the disappointment of an expectation, but an actual change of position that makes it unjust to permit the promisor to resile.

Waltons Stores (Interstate) Ltd v Maher (1988) 164 CLR 387

Maher owned commercial property and negotiated with Waltons to demolish an existing building and construct new premises for Waltons to lease. The parties exchanged draft leases. Waltons' solicitors indicated that approval was forthcoming and that they would advise if any amendments were not agreed to. Hearing nothing further, Maher returned the signed documents and commenced demolition — at considerable expense. Waltons, who had internally decided not to proceed, remained deliberately silent. By the time Waltons formally withdrew, Maher had completed approximately forty percent of the new building. The High Court held that Waltons had induced Maher to assume a binding contract would be executed, had knowingly stood by while Maher acted on that assumption to his detriment, and that it was unconscionable for Waltons to depart from the assumption it had created. Promissory estoppel was available as a cause of action — not merely a defence — and Maher was entitled to relief.

Waltons Stores v Maher is not simply an important case. It is a transformative one. The High Court's judgment, delivered by Mason CJ and Wilson J with Brennan J writing separately, established that promissory estoppel in Australia is not confined to cases where a pre-existing contractual relationship exists between the parties. It extends to representations made in the course of negotiations, before any contract has been concluded — precisely the circumstances where commercial parties are most vulnerable and most likely to act on the basis of apparent consensus.

"The unconscionable conduct which it is the object of equity to prevent is the failure of a party, who has induced the other party to act in a certain way, to fulfil the assumption upon which that other party has so acted."

The implications for Victorian commercial and property practice are significant. A developer who is led to believe that a joint venture partner has committed, and who then expends money on consultants, planning applications and site preparation, may have recourse even in the absence of a formally executed agreement. A business operator who restructures operations in reliance on a landlord's promise to reduce rent may have grounds to resist the landlord's subsequent attempt to recover the full amount. In each case, the question is the same: has one party induced the other to act on an assumption, with knowledge of that reliance, in circumstances where withdrawal would be unconscionable?

The Limits of the Doctrine

Promissory estoppel is not a mechanism for converting every broken promise into a legal remedy. Courts are alert to its potential for overreach and apply its requirements carefully. A party who behaved unconscionably in obtaining the promise in the first place cannot rely on estoppel — the doctrine is rooted in equity, and equity demands clean hands. Equally, a representation that is genuinely qualified — where the maker has made clear that formal approval is required, or that the arrangement remains subject to the execution of documents — will not generally found an estoppel, because no unequivocal assumption has been created.

The remedy granted where estoppel is established is also calibrated to the circumstances. The court asks what relief is necessary to prevent the unconscionable result — which may mean enforcing the assumed contract, compensating for losses incurred in reliance, or something more limited. The objective is not to punish the promisor but to ensure the promisee is not left worse off for having trusted them. This is the same equitable concern that underpins the law's approach to unconscionable conduct more broadly, where one party exploits an imbalance in the bargaining relationship.

Practical Implications

For those engaged in negotiations of any commercial significance, the lessons here are consistent whether you are the party making representations or the party acting on them. Representations made in pre-contractual discussions carry legal risk. Silence in the face of another party's costly reliance on an assumption you know to be false is not a neutral act. And a formal written contract, properly executed, remains the most reliable way to ensure that the rights and obligations of all parties are clear before anyone is asked to act on them.

If you find yourself in a situation where you have relied on a promise that has been withdrawn, or where you are being held to a promise you believed was merely preliminary, the factual detail of what was said, written, and done matters enormously. These cases are rarely straightforward, and the outcome turns on precisely the kind of close analysis that this series is designed to illuminate.

Key Principle

A promise unsupported by consideration may still be binding if the party to whom it was made has acted in reliance on it to their detriment, in circumstances where it would be unconscionable for the promisor to resile. In Victoria, following Waltons Stores v Maher, this principle applies with full force even before a formal contract has been concluded.

Next in this series: misleading conduct and misrepresentation — when a statement made before or during a contract gives rise to liability under Victorian law and the Australian Consumer Law.

This article is intended for general informational purposes only and does not constitute legal advice. The application of contract law principles, including promissory estoppel, is highly fact-specific. If you have a matter involving a disputed promise or pre-contractual representation, you should seek advice from a qualified Victorian solicitor. CMH Lawyers practises in property law, commercial law, litigation and dispute resolution.