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Estoppel is a judicial doctrine existing in various common law jurisdictions.

Its purpose is to achieve equity in contractual matters by preventing (or estopping) a person from going back on their word and is most commonly used and argued where one party has relied on a promise or representation made by another party and suffered a detriment as a result.

Practically, estoppel seeks to prevent a party from acting in a manner which is contrary to what they have promised to do.

Estoppel in Estate Litigation

In the context of a deceased estate, estoppel can arise in several ways – a testator may promise to leave certain property to a plaintiff in exchange for the plaintiff acting to their detriment.

A common example is a testator promising to leave a house to a plaintiff in exchange for care or companionship given by the plaintiff, often for free or at a very low price.

Another example is a testator’s promise to leave their farm to a plaintiff in exchange for labour on the farm, again for little or no pay.

The Elements of Estoppel

The basic elements of proprietary estoppel were established by Justice Kaye in Harrison v Harrison and are set out as follows:

1. A Defendant must first make a promise or undertake to confer an interest in property on the Plaintiff at some point in the future.
2. The Plaintiff must then go on to rely on the promise or undertaking made by the Defendant.
3. The Plaintiff must go so far as to act reasonably in reliance on the promise or undertaking made by the Defendant.
4. In the circumstances, it must be established that the Defendant knew or intended that the Plaintiff would rely on the promises or undertakings made by them.
5. Finally, it must be established that the Plaintiff in relying on the promise or undertaking made by the Defendant acted to their detriment.

A Plaintiff seeking to make a claim by estoppel should use these elements as a framework for any claim brought forward.

In addition to considering this framework, when considering a claim, Courts will also consider a Plaintiff’s ability to establish promissory conduct and detrimental reliance.

Promissory Conduct

Evidence of the representation or promise

A Plaintiff must prove that the Defendant made a promise or representation as to their future and will be required to adduce evidence in support of any assertion made.

In many cases, it can be difficult for a plaintiff to establish that the alleged representation or promise was made, especially in cases where there is evidence directly conflicting what was said or done.

Trial judges have provided commentary and guidance on this point and in the case of McDonald v Dunscombe, the Plaintiff, Margaret failed to establish her estoppel claim. In that case the trial judge looked to the surrounding circumstances and drew inferences that meant that she was not satisfied on the balance of probabilities that Margaret’s version of events had occurred.

How specific must a promise be?

Although there must be a clear promise to do something, what is promised does not need to be precisely defined or defined with the same level of detail as what would be required for a valid contract.

It has been noted however, that vagueness or uncertainty may affect and call into question whether a Plaintiff rightfully relied upon a promise or whether the expectation of the promise was unfairly or unduly relied upon by that Plaintiff.

Is the promise capable of founding an estoppel?

The circumstances surrounding a promise or representation are critical to determining whether an estoppel arises.

For example, a promise or representation made by a testator that they will devise or bequeath an asset may not give rise to an estoppel where the testator does not have capacity to judge the competing moral claims of those who might expect to be beneficiaries under their will.

This was the case in Gill v Garrett where William represented that he would leave his house to Jason. In this case, the trial judge ultimately concluded that the representations made were not the acts of a man who was fully competent. Instead, upon the expert evidence of a medical practitioner, the trial judge considered that these indications were instances where William surrendered to Jason’s suggestions instead.

Detrimental Reliance

To establish detrimental reliance, a Plaintiff must prove that they were induced by the promise or representation of the Defendant to act to their detriment.

In the context of proprietary estoppel cases, this will usually involve some form of life changing, irreversible or profoundly personal and significant detriment.

Is reliance on the promise reasonable?

It is important that the promise made be one that was reasonably a significant factor or contributing cause such that the Plaintiff would, in the absence of the promise, have taken a difference course of action.

Importance of evidence as to detrimental reliance

A Plaintiff’s assertion that they have detrimentally relied upon a representation or promise will be scrutinised and tested in cross-examination, including by reference to documentary evidence.

In this regard, an inference that a Plaintiff would have acted differently but for the representation will be more difficult to establish if it is inconsistent with other direct or circumstantial evidence.

If you have any queries, please contact Anne Pantelidis on 9612 7363