Proprietary estoppel arises in the context of property and creates a proprietary interest in that property in circumstances where: (i) a promise in respect of the property is made to by one person to another who relies upon the promise to their detriment; and (ii) there is a failure to keep that promise that causes an unconscionable outcome. Where a Court finds proprietary estoppel to have arisen, a frequent question which arises is: what is the appropriate remedy?

The Supreme Court has clarified in Guest and another v Guest [2022] UKSC 27 the proper basis for awarding remedies in cases of proprietary estoppel. In such circumstances, the Supreme Court's decision reflects a flexible approach to remedying detriment where proprietary estoppel arises. The general principle is that Courts should consider, in the round, whether a particular remedy would do justice between the parties and would cause injustice to third parties in the circumstances.

It is worth noting that the traditional remedy for proprietary estoppel is to transfer ownership of the property, however the Supreme Court's decision shows that the Courts may consider alternatives such as providing a monetary equivalent where the property has been sold or if its transfer would cause injustice to others. The Supreme Court also noted that this approach does not mean that Courts should seek precisely to compensate the detriment, allowing for a more flexible approach.

Hussein Mithani, an associate in our disputes and private wealth team, considers the decision in more detail below.


The dispute concerns a family who own a farm (the "Farm"). The Claimant is a farmer and is the eldest child of the Defendants who are the current owners of the Farm. The Defendants have two other children, one of whom is a farmer and another who is not. The Claimant lived and worked on the farm with the Defendants for some 32 years, with increasing responsibilities but relatively low pay.

The Claimant had been promised by the Defendants that he would inherit a substantial but unspecified share of the farm and had reflected this promise in wills executed in 1981 providing for the Claimant and his farmer sibling to inherit the farm in equal shares (subject to financial provision of 20 percent of the estate for the non-farmer sibling).

The relationship between the Claimant and the Defendants deteriorated in or around 2008, with the Defendants writing the Claimant out of their will in or around May 2014 and giving the Claimant notice to quit the property he lived in with his family (which was located on the Farm) in April 2015.

The Claimant subsequently issued proceedings alleging that he was entitled to a share in the Farm or its monetary equivalent on the grounds of proprietary estoppel.

First Instance Decision

At first instance, the trial judge held that the Claimant had satisfied the grounds for proprietary estoppel to arise as he worked on the Farm for little financial reward because he reasonably relied, to his detriment, on various assurances made by the Defendants as to his right to the Farm after they passed away.

The trial judge ordered the Defendants make an immediate payment of £1.3 million (subject to certain adjustments) to the Claimant to satisfy his expectation as to what he would have inherited. This was calculated as 50 percent of the value of the dairy farming business plus 40 percent of the value of the freehold land and buildings at the Farm.

The Defendants subsequently appealed.

Court of Appeal Decision

Before the Court of Appeal, the Defendants argued that the remedy was incorrect and should not have been based on the Claimant's expected inheritance. The Defendants argued that the award should, instead, be calculated by reference to the Claimant's contribution to the value of the Farm or his loss of opportunity to work elsewhere. The Defendants also argued that the remedy wrongly accelerated the Claimant's expectation, as he had not expected to receive an interest in the farm until the Defendants' death.

The Court of Appeal dismissed the appeal on the basis that it was appropriate to order a remedy by reference to Andrew's expectation. The Defendants then appealed to the Supreme Court.


A majority of the Supreme Court (Lord Briggs, with whom Lady Arden and Lady Rose agreed) allowed the appeal in part. The majority substituted alternate remedies and gave the Defendants the choice of either: (i) putting the farm into trust in favour of the three children, or (ii) paying compensation to the Claimant now but with a reduction properly to reflect his earlier-than-anticipated receipt (with such reduction to be agreed between the parties or if not agreed to be remitted back to the Chancery Division).

Lord Briggs (who delivered the judgment on behalf of the majority) noted that, historically, the usual remedy was for the Courts to enforce the promise. He noted this is the "normal and natural remedy... because that was the simplest way to prevent the unconscionability..." However, Lord Briggs noted that this remedy was always discretionary and the Court could substitute a payment based upon (but sometimes less than) the value that the promisee expected to receive.

Lord Briggs went on to note that he rejected the idea that the aim of a remedy for proprietary estoppel is based on compensating the detriment suffered by the promisee. Instead he noted the approach to be taken was as follows:

  1. The Courts should start by determining whether going back on the promise is unconscionable at all in the circumstances.
  2. If it is, then the Courts should proceed on the assumption that the simplest way to remedy that unconscionability is to enforce the promise (i.e. transfer the property in question), but should consider alternatives such as providing a monetary equivalent when it would be appropriate to do so.
  3. In determining the remedy (whether it be enforcement of the promise or providing the monetary equivalent) the Courts must consider whether that remedy would be out of proportion to the detriment to the promisee. If it is, then the Courts may need to limit the remedy. However, in undertaking this exercise, the Courts should not seek to precisely compensate the promisee for the detriment caused.
  4. If the remedy involves acceleration of a future promised benefit (as it did in this case), the Courts should generally require a discount for accelerated receipt.
  5. Finally, the Courts should ask themselves "whether it would do justice between the parties, and whether it would cause injustice to third parties." The yardstick for that justice assessment will always be whether, if the promisor was to confer that proposed remedy upon the promisee, he would be acting unconscionably.

In applying these principles, the majority found that the trial judge did not adequately discount the sum awarded to reflect the fact that Claimant would receive compensation earlier than he had expected to inherit an interest in the Farm.

A minority of the Supreme Court (Lord Leggatt and Lord Stephens) would also have allowed the appeal but on substantially different grounds and would have substituted a different remedy. Lord Leggatt who gave the judgment on behalf of the minority, considered that the core principle underpinning relief for proprietary estoppel is to prevent a party going back on a promise without ensuring that the party who relied on that promise will not suffer a detriment as a result of that reliance.

Lord Leggatt noted that the Courts may achieve this by compelling performance of the promise (or order equivalent payment) or award compensation to put the promisee into as good a position as if they had not relied on the promise. Lord Leggatt noted the Courts should adopt whichever method results in the minimum award necessary to meet the aim.

On this basis, the minority would have awarded the Claimant £610,000 to compensate for the detriment he has suffered as a result of working on the farm in reliance upon his parents' assurances as this reflects the estimated additional amount the Claimant would have earned by working elsewhere.


Lord Briggs started his judgment with "One day my son, all this will be yours". This really highlights that these sorts of cases typically arise in family business situations where a family member (or family members) are promised some form of inheritance and rely on that promise to their own detriment. Sometimes, as it was in this case, it is the son of a farmer who has been told he will inherit a substantial part of the farm and works long hours for little to no wages in reliance on that promise. Or it could be a scenario where an individual works for the family business and abandons other lucrative opportunities because they are promised that they will one day own and run the company.

This decision shows the flexible options open to the Court relying on equitable principles which is welcome to ensure the remedies are equitable and just. However, it does reduce certainty in respect of remedies which may impact on how such litigation is conducted. This more flexible approach – and thus uncertainty – may lead to more settlements in this area (especially where the matter is not straightforward or there are other people who are inheriting) or it could have the opposite effect if the parties decide to gamble on the basis they think they may win more. It remains to be seen what the consequence may be, but our own experience is that unfortunately disputes involving families can become acrimonious and go to the bitter end.

Another consequence, alluded to by Lord Briggs, is that the Courts may require expert evidence when calculating a discount for an earlier than anticipated receipt.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.