Legal Update
Proprietary estoppel after Guest v Guest
14 November 2022

Proprietary estoppel after Guest v Guest

Author: Sean Kelly

Written by Sean Kelly


For some time, the Court has had to deal with an increasing number of proprietary estoppel claims brought by a son against his parents in relation to the family farm. This may be the result of changes in family relationships or just due to the increasing value of farming land. The majority of claims used to be made against the executors of the parents following the realisation by the son that the will contained no bequest to him of the family farm.

The new norm is for the claim to be made during the lifetime of the parents following a breakdown in the relationship. The ability to make such a claim during the lifetime of the parents was first established by the decision of the Court of Appeal in Gillett v Holt [2001] Ch 210. Although some claims are made by daughters (such as Davies v Davies [2016] EWCA Civ 463), the majority are still made by sons.

In most cases the promise, representation or assurance relied upon is “One day, all this will be yours”. The promise leads to the expectation that all or part of the family farm will pass to the son at some point in the future and the son spends his entire life working on the farm (often at low pay) instead of pursuing other career options. There is no contract to rely upon and the lack of certainty in the promise precludes a constructive trust claim. The son has to make his claim in proprietary estoppel.

Proprietary estoppel is a judge-made remedy which had been the subject of considerable case law including two decisions of the House of Lords (that is to say Cobbe v Yeoman’s Row [2008] 1 WLR 1752 and Thorner v Major [2009] 1 WLR 776) albeit that such decisions are of limited scope. Thorner v Major confirmed that the promise could be in very general terms and it was the function of the Court to interpret it. Cobbe v Yeoman’s Row confirmed that proprietary estoppel had no application to commercial negotiations.

The Court has usually adopted a two-stage test. In the first stage, it determines whether “an equity” has been raised which makes it necessary for the Court to intervene to provide a remedy. The second stage is the crafting of a remedy to “satisfy the equity”. The principles are set out succinctly by Lewison LJ in Davies v Davies at paragraph 38 in a passage that has become a template for later decisions:

1) Deciding whether an equity has been raised, and if so, how to satisfy it is a retrospective exercise looking backwards from the moment when the promise falls due to be performed and asking whether, in the circumstances which have actually happened, it would be unconscionable for a promise not to be kept either wholly or in part.

2) The ingredients necessary to raise an equity are (a) an assurance of sufficient clarity (b) reliance by the claimant on that assurance and (c) detriment to the claimant as a consequence of his reasonable reliance

3) However, no claim based on proprietary estoppel can be divided into watertight compartments. The quality of the relevant assurances may influence the issue of reliance; reliance and detriment are often intertwined, and whether there is a distinct need for a “mutual understanding” may depend on how the other elements are formulated and understood.

4) Detriment need not consist of the expenditure of money or other quantifiable financial detriment, so long as it is something substantial. The requirement must be approached as part of a broad inquiry as to whether repudiation of an assurance is or is not unconscionable in all the circumstances.

5) There must be a sufficient causal link between the assurance relied on and the detriment asserted. The issue of detriment must be judged at the moment when the person who has given the assurance seeks to go back on it. The question is whether (and if so to what extent) it would be unjust or inequitable to allow the person who has given the assurance to go back on it. The essential test is that of unconscionability.

6) Thus, the essence of the doctrine of proprietary estoppel is to do what is necessary to avoid an unconscionable result.

7) In deciding how to satisfy any equity the court must weigh the detriment suffered by the claimant in reliance on the defendant’s assurances against any countervailing benefits he enjoyed in consequence of that reliance.

8) Proportionality lies at the heart of the doctrine of proprietary estoppel an permeates its every application. In particular, there must be a proportionality between the remedy and the detriment which is its purpose to avoid. This does not mean that the court should abandon expectations and seek only to compensate detrimental reliance, but if the expectation is disproportionate to the detriment, the court should satisfy the equity in a more limited way.

9) In deciding how to satisfy the equity the court has to exercise a broad judgmental discretion. However, the discretion is not unfettered. It must be exercised on a principled basis.

Lewison LJ went to set out the “lively controversy” as to the purpose of the remedy, that is to say whether the purpose was to give effect to the claimant’s expectation unless it would be disproportionate to do so or whether it was to compensate the claimant for the detriment which he had suffered as a result of reliance on the promise.

The “lively controversy”

In Guest v Guest [2022] UKSC 27 (delivered on 19th October 2022) the Supreme Court was required to resolve this “lively controversy” and determine the purpose of the remedy.

The facts in Guest v Guest are complicated given that the promises were given over the whole lifetime of the son. However, for the most relevant facts could be said to be as follows:

1)  There was a breakdown in the relationship between the claimant son and his parents during their lifetime. Accordingly, the claimant son was seeking an interest in the family farm now rather than when it was promised and his interest was being accelerated.

2) The family farm had a farmhouse which was still occupied by the parents

3) As a result of repeated promises over his whole life, the claimant son expected to conduct the dairy farming business until the death of his father. On the death of the second parent to die, the claimant son expected to receive one half of the dairy farming business and one half of the farm (including the farmhouse). A brother was to receive the other half of the farm.

4) While the claimant son and the parents had been in partnership for a short period, this partnership had been dissolved and no consideration was given to the effect of it.

5) Any remedy would involve the sale of the dairy business and the farmhouse. This was bound to create an immediate CGT charge.

In contrast with Davies v Davies (where liability and remedy were tried separately), HHJ Russen, QC ([2019] EWHC 869 (Ch)) tried both together. The parents put all of their efforts into defeating the claim and made no detailed submissions as to remedy. The Judge determined that it was unconscionable for the parents to go back on their promises and that a remedy should be provided to satisfy the equity. The Judge considered that the most proportionate remedy was to make a lump-sum award to the claimant son calculated on the following basis:

1) 50% after tax of the market value of the dairy business

2) 40% after tax of the value of the farm and 40% after tax of the value of the farmhouse taking into account a decrease to be generated by the assumption that the same was subject to a notional life-interest for the parents.

Other than the reference to the assumed life-interest of the parents, there was no express reference to the effects of acceleration and how there could be a discount to reflect this effect.

The Court of Appeal refused the appeal, so the award was not altered.

In the Supreme Court, there are two competing opinions. The majority opinion (3) is given by Lord Briggs, with the minority opinion (2) given by Lord Leggatt. They could not be more different.

1) For the majority (paragraph 61) the unconscionability is the repudiation of the promise, and the purpose of the remedy is to prevent the defendants from doing so. It must naturally follow that the remedy to be crafted by the Court will involve ensuring that the reasonable expectation of the claimant is fulfilled save where this would be “out of all proportion to the detriment”. The burden of proof is on the defendant to plead and prove that the remedy would be out of all proportion to the detriment (paragraph 76). Although not stated expressly, as a matter of logic, this would also mean pleading and proving some other more proportionate remedy to achieve the same purpose.

2) For the minority (paragraph 191) the unconscionability is not the failure by the defendant to keep a non-binding promise. It is the failure by the defendant to accept responsibility for the consequences of the claimant’s reasonable reliance on the promises. Accordingly, the remedy is there to deal with the consequences of detriment, and this is the starting point for crafting any remedy. The minority then went on to seek to determine the real financial loss suffered by the son.

The majority did not object to the principle of a lump-sum order but objected to the order made by HHJ Russen, QC due to its failure to deal expressly with the effects of acceleration. However, it did not substitute its own order. If necessary, this issue would be remitted to the trial judge. The minority substituted a detriment-based award calculated so as to accord with the loss of earnings or other lost benefits of the claimant son.

It is unfortunate that it has taken so long for the purpose of this remedy to be determined at the highest level. The two views cannot be reconciled, and the position has now been resolved by the principle of majority rule. The starting point is that the Court should craft its remedy in order to ensure that the reasonable expectation of the claimant is satisfied unless this would be out of all proportion to the detriment. It is for the claimant to set out what his expectation is and how this is to be satisfied by order of the Court. The claimant needs to plead and prove detriment, but not in financial terms. It is for the defendant to set out why this would be out of all proportion to the detriment and put forward another remedy to achieve the same end.

As regards the test of unconscionability, proportionality is still important. Repudiation of the promise (or refusing to give effect to the expectation if different) only requires the intervention of the Court if this is unconscionable. The extent of the detriment suffered is relevant to this. As the majority clarified, it is not necessarily unconscionable for parents to repudiate the promise if their financial circumstances change.

In the majority of farming cases, fulfilment of the expectation will involve the transfer of assets which are in monetary terms out of all proportion to the financial detriment suffered by the son in working on the farm for his whole life. The value of many of the family farms which are the subject of the most recent cases is measured in millions if not tens of millions of pounds.

This is a natural result of the increase in the value of farming land. Clearly, the majority in the Supreme Court took the view that this increase in the value of land is not a good reason of itself to refuse to fulfil the expectation. Something more is required. This might involve prejudice to the interests of other members of the family or the need to provide for the parents in retirement.

Outstanding Issues

Following the decision of the Supreme Court, the following issues remain unresolved:

1) Will the need to fulfil the claimant’s expectation make the Court more reluctant to provide any remedy?

2) What factors make it out of all proportion to fulfil the expectation of the claimant?

3) How should the Court deal with tax concerns?

4) How should be Court deal with the acceleration which results from having to provide a remedy during the lifetime of the parents?

5) What difference (if any) would it make if the parents and the son had been partners.

1) Provision of some remedy

Some of the decisions of the Court involving a lump-sum payment can be explained on the basis that the Court considered that the claimant ought to be compensated in some way but not by the fulfilment of his expectation. Jennings v Rice [2002] EWCA Civ 159 would be the most obvious example. If proportionality were to permeate every part of the judicial process, then it would allow the Court to award something which allows the claimant to progress with his life without fulfilling his expectation of ownership of a particular farm or farming somewhere else. It remains to be seen whether the requirement to fulfil the expectation in full reduces the number of successful claims. 

2) Disproportionate relief

It is always difficult to apply other principles of equity by analogy. However, where a person receives money which is transferred in breach of trust, his liability in knowing receipt is based on his knowledge (express or implied) of the transaction. The underlying test is one of unconscionability. If it is unconscionable for him to keep the money, he has to pay it to the beneficiary of the trust.

There is no question of him paying only some part if it depending upon how unconscionable it is for him to receive it. A sliding scale principle does not work with unconscionability. It is a binary issue. Logically, if it is unconscionable for the parents to resile from their promise to transfer all or part of the farm to their son, then his expectation can only be fulfilled by a transfer of some, or all of that particular farm and a lump-sum payment can never be an adequate alternative.

A lump-sum payment can allow the son to operate a farm somewhere else. However, that was not the expectation. The majority in the Supreme Court do not seem to be troubled by this. On this basis, the factors which a defendant can plead and prove include (a) the interests of other members of the family (b) the need for the parents to be provided with an income and housing in retirement and (c) the availability of means by which the son can acquire a similar farm.

3) Tax concerns

In the normal course of events, if the son is to inherit the family farm upon the death of the last parent to die, then there will be 100% agricultural relief for inheritance tax. Any CGT will be washed out. If the family farm is given to the son during the lifetime of his parents, then this will be a PET (albeit one to which agricultural relief could apply). As it is a PET, CGT is chargeable immediately at the true market value. If the son elects to do so, he can hold over the gain for CGT purposes. While it is unwise to predict future tax changes, it is reasonable to assume that CGT rates will increase significantly to fund the budget deficit.

Bringing a proprietary estoppel claim during the lifetime of the parents can give rise to a tax charge. If the farm needs to be sold to a third party, this will give rise to immediately chargeable CGT. If the son is to receive all or part of the farm, he will need to agree to accept the election for him to be taxed and for the CGT be rolled over.

It would be fair to say that the Court is not particularly concerned about the effects of taxation on the crafting of the remedy. It is often said that it is not the job of the Court to save the party's tax. In any event, the Court is poorly equipped to consider the tax aspects of any remedy. Orders requiring the farm to be transferred to the son subject to continuing periodic payments to the parents (such as Moore v Moore [2018] EWCA Civ 2669) have been made. Such a route has the merit of avoiding the CGT on sale, but this is not the reason for the Court’s choice of the route. 

4) Acceleration

There is really no assistance from the Court in any case as to how the acceleration in the entitlement of the son to the family farm should be dealt with.

As regards the lump-sum method, the effects of acceleration were not considered in any detail in Davies v Davies. While the lump payment awarded by the High Court in Guest v Guest was criticized, no real guidance was provided as to how it should be done. There was merely a suggestion that actuarial tables could be used.

As to the transfer of the farm subject to a periodic payment method, the order of the High Court in Moore v Moore provided for a weekly payment of £200 to the parents, in relation to a farm worth several million. While this payment was set aside as being far too low and a higher payment substituted, there was no real guidance as to how such a figure should be calculated. Presumably, it should bear some relation to the value of the farm to be transferred or (at least) the ability of the farm to generate income. 

5) Partnership issues

These were not addressed in Guest v Guest. In Moore v Moore the claim arose in relation to an interest in a farm held in partnership. Even though the case started as a winding-up claim, there was no real discussion as to whether the existence of a partnership affected the nature of the expectations of the son or the relief to be granted. These issues remain unresolved.

When a parent takes a son into partnership, the relationship must change to a predominantly commercial one. The expectation of the son as regards what is to occur when the partnership is dissolved ought to accord with the position under the partnership agreement or the general law of partnership. The decision in Cobbe v Yeoman’s Row precludes a proprietary estoppel claim in relation to a purely commercial relationship. Logically, the decision should preclude the son from asserting rights greater than those which arise as a partner. Unfortunately, this point was not raised in Moore v Moore.

Another feature of partnership proprietary estoppel claims is the widespread assumption that all land farmed by a partnership is partnership land. A son might work on the family farm as a partner for many years on the assumption that the farm is partnership property only to realise much later that it is still owned by the parents. In such a situation, there is no promise. There is merely a misunderstanding of the law.

The role of mediation

In relation to the assessment of whether it would be unconscionable for the parents to repudiate the promise made by them, mediation has a limited role. However, in most cases it is relatively obvious whether the son has a claim with merit and the real issue is as to remedy.

In relation to remedy, mediation is really the best way of proceeding. The Court is ill-equipped to provide a sensible pragmatic solution to the problem especially if tax is an issue. A mediator will probably be concerned primarily with what the claimant requires in order to continue to farm whether at the family farm itself or otherwise. In reality, there are likely to be many different solutions each with pros and cons which can be examined in detail during a mediation.


Sean undertakes a broad range of chancery and commercial work with emphasis on partnerships, company law, banking, contractual disputes, land law (including land registration), landlord and tenant and administration of estates.