Commentary on Guest v Guest

In October 2022, the Supreme Court handed down judgment in Guest v Guest [2022] UKSC 27. The case provides guidance on how the level of relief for a proprietary estoppel claim should be assessed. Is the purpose of the remedy to give effect to the claimant’s expectation or to compensate the claimant for the detriment suffered?

Proprietary estoppel

Proprietary estoppel claims can be brought to enforce a promise made to a claimant in respect of property or land that has not been fulfilled or later reneged on.

There are three elements that must be satisfied to successfully bring a claim:

  1. A clear assurance is made to the claimant
  2. The claimant has relied on that assurance
  3. The claimant has suffered a detriment as a result of reasonable reliance on the assurance

Typically, a proprietary estoppel claim will arise following the promisor’s death ie the deceased has promised some form of inheritance will be left to the promisee under their Will and it is later discovered that this is not the case. However, a claim can arise in other circumstances while a testator is still alive as occurred in the matter of Guest v Guest.


The case involved a family run farm, owned by the parents of the Claimant, Andrew Guest. The Claimant had worked on the farm for over 30 years, living rent-free but receiving a very low wage. His parents had made various assurances to him, which left him with the expectation that he would inherit a significant (but unspecified) proportion of the farm on their deaths. 

In 2014, after an unfortunate breakdown in familial relations, the Claimant left the farm and was subsequently disinherited from their estates entirely.

In 2017, the Claimant brought a claim of proprietary estoppel against his living parents for a share of the farm or a lump sum of equivalent market value. He argued that his parents had promised him he would inherit a substantial part of the farm which he had relied on to his detriment by devoting his life to working on the farm and receiving little compensation. 

High Court decision

The Judge at first instance found in favour of the Claimant. The Judge said that clear assurances had been given over a significant period of time, which were supported by the terms of earlier Wills and partnership agreements. The exact share of the inheritance had been left undetermined, but it was clear that the Claimant’s share would be significant. Reliance and resulting detriment were found to be obvious on the facts as the Claimant had worked hard to develop the farm; the benefit of free accommodation was insufficient to off-set his low wage. The Judge decided therefore that it would be unconscionable for the Claimant not to inherit something – the more difficult question was what should he receive.

The Judge made an order based on the Claimant’s expectations, being that he would take over running certain elements of the farm in due course and inherit those parts in full. The Judge ordered the Claimant’s parents to pay the Claimant a lump sum of £1.3 million, equivalent to 50% of the farming business and 40% of the value of the farmland and farm buildings (after tax). Notably, this award required the Claimant’s parents to sell the farm but the Judge determined that a “clean break solution” was necessary given the breakdown in relationships. The Claimant would therefore receive his share during his parents’ lifetimes.

Court of Appeal

The Claimant’s parents appealed the decision on the grounds that the award:

  1. Had been assessed incorrectly as relief based on the Claimant’s expectation was inappropriate
  2. Went beyond what was necessary to avoid an unconscionable result
  3. Should not have been granted whilst the parents were still alive

The appeal was dismissed by the Court of Appeal. The parents then appealed to the Supreme Court.

Supreme Court’s decision

The key issue before the Supreme Court was whether the remedy was appropriate and, more specifically:

  1. Whether a claimant’s expectation is the correct starting point when considering the remedy
  2. Whether the remedy granted went beyond what was necessary in the circumstances

The Claimant’s parents argued that the Claimant should only be compensated for the detriment suffered. In addition, the promise had been made on the basis that the Claimant would receive his share on the second death and, therefore, he was receiving an additional benefit by obtaining the lump sum now. 

It was held that the purpose of the doctrine of proprietary estoppel is the prevention or undoing of unconscionable conduct. The starting point when determining the remedy therefore should be to hold the promisor to the promise and fulfil the reasonable expectation of the claimant, unless that would be “out of all proportion to the detriment” suffered. This is a matter for the defendant to prove and propose an alternative or reduced award accordingly. 

The Court reinforced, however, that repudiation of the promise only requires the Court’s intervention if it would otherwise be unconscionable. This may not always be the case, for example, if the promisor’s financial circumstances have changed or if doing so would severely prejudice another beneficiary.

The Court found that the Claimant’s parents should have been given the option to choose from two appropriate remedies: they could put the farm into a life interest trust for the Claimant to inherit on their deaths or they could sell the farm during their lifetimes to pay the Claimant a lump sum. Any such sum however needed to be significantly discounted to take account of the Claimant’s accelerated receipt ie to reflect the benefit gained by the Claimant in receiving the sum sooner than he otherwise would have done, the Court does not have the power to award a claimant more than they have been promised or expected to receive.


The case demonstrates the wide discretion the Court has in respect of remedies to be awarded in proprietary estoppel claims, which will turn on the facts of each case. While the judgment therefore does not provide much certainty as to the likely outcome of matters for future claimants and defendants, it is clear overall that any award should not go beyond what is necessary to remedy an unconscionable outcome.

More widely it is important to note that, as a result of the increase in the value of farmland, in many farming cases the fulfilment of the claimant’s expectation may involve a transfer of assets which are, in monetary value, disproportionate to the financial detriment suffered. The Court does not view this as unconscionable. Individuals should therefore exercise caution when making promises of this nature and take legal advice to carefully document any agreements reached during their lifetime.

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