Disputes over property inheritance are particularly sensitive, often involving conflicting accounts, historical contributions and verbal assurances that were never committed to writing. In such cases, a crucial legal doctrine comes into play: proprietary estoppel.

In this blog post, Walker Foster’s contentious probate and inheritance disputes specialist Guy Platon explores the legal foundations and real-world application of proprietary estoppel, drawing on a recent High Court case that highlights how the courts approach these claims.

What is a proprietary estoppel claim?

Claims for proprietary estoppel (PE) have become increasingly common in commercial, family and contentious probate matters. A PE claim arises where a party acts to their detriment in reliance upon a representation made by another (usually, but not necessarily, the deceased). The promisee can therefore ask the court to intervene and enforce the promise.

If proven, such claims can be very effective, as they can override the provisions of a will or the rules of intestacy.

A typical scenario for this kind of PE claim is within farming estates, as they tend to share common characteristics:

• A succession of generations working on the farm from an early age and over a considerable period (particularly the male children)
• A sprawling estate comprising multiple land parcels and buildings
• A lack of written contracts and a reliance on verbal assurances (e.g. "one day this will all be yours")

For example, a parent might promise a child that they would inherit the property after their death (‘representation’). In reliance on that promise, the child may either work on the property or forgo the opportunity to attend university or pursue a career elsewhere (‘detrimental reliance’).

Provided these elements are met, the child may be able to claim that PE exists - even if the property in question is subsequently given away, sold, or disposed of under a will.

Cleave v Cleave

As with most legal concepts, a case example often provides the clearest illustration. A recent case heard in Bristol - Cleave v Cleave [2024] EWHC 2492 - demonstrates the current principles effectively.

This judgment helpfully sets out the relevant legal principles (originally from an earlier case) relating to proprietary estoppel as follows:

• The ingredients necessary to raise an equity are:
• an assurance of sufficient clarity;
• reliance by the claimant on that assurance; and
• detriment to the claimant as a consequence of that reasonable reliance.
• The court should look back from the time the promise is due to be performed and ask whether, in light of what actually happened, it would be unconscionable for the promise not to be kept, either wholly or in part.
• No PE claim can be divided into watertight compartments. The quality of the relevant assurances may influence the issue of reliance; “reliance and detriment are often intertwined…”
• Detriment need not involve the expenditure of money or other quantifiable financial loss, so long as it is something substantial.
• There must be a sufficient causal link between the assurance relied upon and the detriment asserted. The question is whether (and if so, to what extent) it would be unjust or inequitable to allow the person who gave the assurance to renege on it.
• 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 benefit the claimant enjoyed as a result of that reliance.
• Proportionality lies at the heart of the doctrine. In particular, there must be a proportionate relationship between the remedy and the detriment the remedy seeks to address.

The facts of the case

The parties involved were Mary, aged 91, her son Irving and his wife, Caroline. The property in question was a 52-acre working farm comprising several outbuildings, a paddock, an orchard and later, a barn conversion.

Irving and Caroline (the ‘Claimants’) brought a proprietary estoppel claim on the basis that Irving had devoted his working life to the farm, earning low wages in reliance on assurances from his parents that he would one day inherit it. It was accepted that Irving had indeed helped on the farm from a young age, although the extent of his contribution was disputed. Nevertheless, it was agreed that Irving earned only £125 per month, which increased to £250 after 2016. The farm operated at a loss.

By 1991, Irving had taken on most of the farm work. In 2018, he began a relationship with Caroline, whom he married in 2022. Irving’s parents later decided to convert a separate barn into a home for Irving and Caroline, partly to support Irving, who had developed Parkinson’s disease.

It was accepted by all parties that Caroline invested approximately £127,000 of her own money into the conversion. Irving contributed around £200,000 from the sale of land and other assets. Over time, the barn conversion was expanded to include an annexe for Mary, due to her declining mobility and health. Irving’s father, Elwyn, passed away in April 2021.

Shortly after Mary moved into the annexe - in July 2022 - a dramatic incident occurred. A serious altercation between the three parties led to a seemingly irreparable breakdown in their relationship, followed by Mary’s alleged suicide attempt. She also accused Caroline of attempting to suffocate her with a pillow.

At that point, the main barn was not yet habitable, and the Claimants were still living in a caravan on the site. The Claimants contended that Mary’s behaviour had been deteriorating prior to this incident. Mary subsequently changed her will to disinherit Irving, Caroline and her daughter entirely, prompting the Claimants to initiate legal proceedings.

Irving’s case

Irving gave a statement detailing the promises made by his parents that he would inherit the farm, along with evidence of job offers from third parties that he had declined - illustrating his detrimental reliance. His statement included details of a request he had made to formalise these assurances in writing, which his parents rejected, insisting that “it was all going to him anyway”.

Mary gave evidence confirming that Elwyn wanted Irving to have the farm (“of course we did, both of us”) and that they had conveyed this to Irving. Irving maintained that repeated and clear representations had been made regarding the property being left to him, even though Mary created a new will after their July 2022 altercation.

He had committed his working life to the farm, a fact corroborated by several witnesses who gave consistent and credible testimony in support. He also presented evidence showing his wages were significantly lower than standard market rates for similar agricultural work.

Additionally, Irving had turned down another job opportunity. Both he and Caroline had made substantial financial contributions to the farm and the barn conversion. It was an overwhelmingly strong claim, which arguably should never have needed to go before the court.

As a remedy, Irving sought immediate transfer of the barn conversion and 90% of the land (referred to as ‘trust land’ in a separate head of loss, but effectively comprising most of the 52 acres), while allowing Mary to retain the farmhouse and the remaining 10%.

Mary’s defence

In her defence, Mary partially relied on the equitable maxim of “clean hands”. This is applicable in proprietary estoppel claims, as they fall within the equitable jurisdiction of the court, where the longstanding principle applies: “He who comes into equity must come with clean hands.” This means that the claimant must have behaved properly, particularly in relation to the relief they seek.

Mary alleged that Irving had employed bullying and oppressive tactics to pressure the transfer of the farm, and therefore should be barred from claiming equitable relief, even if the substantive claim was otherwise valid. This argument was rejected.

She also contended that Irving’s evidence of detrimental reliance was insufficient, noting that he received “free board and lodging” while working on the farm.

The judge’s decision

The judge found Mary’s evidence to be unreliable, despite its emphatic delivery. He clearly favoured the evidence provided by Irving and Caroline.

The court accepted that the family had previously been a close unit but noted that Mary had turned against the Claimants in a “startlingly intense way”. Interestingly, the court found that minor inconsistencies in Irving and Caroline’s evidence lent credibility to their account - indicating truthful testimony, as opposed to a rehearsed or “false united front”.

On the PE claim, the judge concluded:

• The Claimants’ evidence was preferred and accepted;
• Irving had been told from a young age that the farm would one day be his, and had stayed on with that understanding;
• The “clean hands” defence was dismissed as unsupported by the facts;
• Irving had been “positively pressured” into rejecting alternative employment, and evidence suggested he may have forfeited over £500,000 in potential earnings as a result.

Applying these facts to the established principles, the judge held that Irving had clearly acted to his detriment based on a longstanding assurance that he would inherit the farm. It would therefore be unconscionable for Mary to renege on that promise.

The final ruling

The court then considered the appropriate remedy or award. It referred to the principles set out in Guest v Guest, which establish that, if reneging on the promise is unconscionable in the circumstances, then the default remedy should be enforcement of the promise.

However, if enforcing the promise would be wholly disproportionate to the detriment suffered, the court may limit the remedy. It can therefore either compel performance of the promise, or award compensation to place the claimant in the position they would have been in had they not relied on the promise.

This flexibility was applied in the present case, taking into account Mary’s ongoing care and accommodation needs. The court ordered that:

• The renovated barn should be transferred to the Claimants;
• The remainder of the property was to be placed into trust on a 90/10 basis in favour of the Claimants and Mary respectively;
• Mary retained the farmhouse, an orchard and a paddock - though these assets might need to be sold to fund her care.

The case was notably costly, involving seven days of hearings, multiple witnesses, and the engagement of King’s Counsel. Despite this, no new points of law were raised - it was purely a restatement and application of existing principles. Given the strength of the Claimants’ proprietary estoppel case, it arguably should have settled much earlier, possibly at pre-issue mediation. Having a 91-year-old in the witness box in such a high-stakes dispute was, by any measure, far from ideal.