← The hardest concepts in Australian law
In one breath
Equitable estoppel prevents a person from going back on an assumption they encouraged another to adopt, when the other has relied on it to their detriment and it would be unconscionable to depart from it. The remedy is not fixed: the court gives the minimum needed to do justice, which may be less than the promise.
The picture
The scaffold around a half-built wall
A builder is told by a neighbour, “Go ahead and extend your wall onto my strip; I’ll sort out the boundary papers later.” The builder buys bricks and begins work. When the wall is half built, the neighbour withdraws the permission. The law does not let the neighbour keep everything, and it does not force the neighbour to finish the wall. It puts up a scaffold: a support, erected because of the neighbour’s encouragement, to hold up what the builder’s reliance has built and stop it collapsing on the builder.
The scaffold is only as large as the damage requires. If the builder’s loss is a few bricks and some labour, the scaffold is a payment for those. If the builder has put up an entire house believing it would stand, the scaffold may be a right to stay. The court asks in sequence what assumption was encouraged, what the other did in reliance and what they would lose if the assumption failed, and what is the least the court must do to avoid an unconscionable result.
Where the picture stops working
A scaffold is a material thing erected after the damage. Estoppel starts earlier, in the encouragement, and takes into account the whole conduct of both parties. The picture also hides that the High Court has not settled every question, such as whether there is one unified estoppel across common law and equity, and what the remedy should be in every case.
How it really works
- 1Place the rule. It is general law (equity) and is the same across the country, although State statutes about writing and formalities may interact with it.
- 2Identify the assumption: a belief that a legal relationship exists or will exist, for instance that an interest in land will be given, and not just a hope.
- 3Show that the party now denying it encouraged the assumption by words or conduct, or stood by in silence when it was unconscionable not to speak.
- 4Show reliance and detriment. The other party acted or held back in reliance, and would suffer if the assumption were abandoned.
- 5Ask whether it would be unconscionable to depart from it. If so, choose the relief: the minimum equity needed to do justice, which may be compensation, a lien, a licence or the promised thing, having regard to third parties’ rights.
Why people get it wrong
- Assuming estoppel makes the promise a contract. No consideration is needed, but the remedy is limited to the detriment.
- Thinking a promise alone is enough. Reliance and detriment are required.
- Believing the remedy is always to enforce the promise. It is the minimum needed to prevent unconscionable loss.
- Treating it as a shield only. The High Court has allowed it to found a claim.
- Taking an expectation or hope for an assumption. A party who knows the other may not proceed is in a weak position.
A worked example
The facts are invented
Noreen tells her niece Lena, “The cottage will be yours when I’m gone; move in and look after me.” Lena gives up her job in the city, moves in, and spends eight years caring for Noreen and repairing the cottage. Noreen’s will leaves the cottage to someone else. Lena can plead estoppel: the assumption was encouraged, she relied on it, she suffered detriment in lost earnings and work, and it would be unconscionable for the estate to deny it.
The remedy depends on the facts. If her contribution was large and the estate has no other claim of weight, the court may order the cottage transferred to her. If she was housed and fed for eight years and paid back in other ways, a sum of money may do justice. Change the facts: Lena had given up nothing and merely enjoyed living there. With no detriment there is no estoppel.
Try it
Sam is told by a landowner that Sam may build a pavilion on the landowner’s block and will be allowed to buy it. Sam spends savings building it. The landowner then refuses to sell. What is the best account of what a court may do?
Landmark authorities
Read the sources themselves; this list is a starting point.
- Legione v Hateley, (1983) 152 CLR 406
- Waltons Stores (Interstate) Ltd v Maher, (1988) 164 CLR 387
- Commonwealth v Verwayen, (1990) 170 CLR 394
- Giumelli v Giumelli, (1999) 196 CLR 101
Where to go next
Courses
Case briefs
Dictionary
More hard concepts in Australia law
- Unconscionable conduct (Equity)
- Accessory liability and strangers to a trust (Equity)
- Torrens title and indefeasibility (Property law)
This page is an educational overview. It is not legal advice and not a substitute for the sources: the statute, the rule, the case itself. Australia is a federation: the Commonwealth, the six States and the Territories each make law, and the High Court is the final court for all of it. The common law, by contrast, is one law across the country. Each page says whether the rule is constitutional, federal or common law shared by every jurisdiction, or State-by-State legislation that varies, and flags where the States and Territories differ. Each page states the usual formulation of the rule and names landmark decisions; check the primary sources of your own jurisdiction before relying on any rule.