Proprietary Estoppel and Wills UK (2026): Promises About Inheritance, Detrimental Reliance and Remedies

Proprietary estoppel is an equitable doctrine that allows a person to claim a proprietary interest in land (or other property) where the strict legal position (e.g. a will or the intestacy rules) would otherwise deny them any entitlement. In the context of wills and inheritance, it most commonly arises where: (a) a person was promised they would inherit a farm, house, or business; (b) they relied on that promise by working for low wages, making improvements, or giving up other opportunities; (c) the promise was not kept — the promisor died leaving a will that gives the property to someone else (or leaving no will). THE THREE ELEMENTS — established in Thorner v Major [2009] UKHL 18 per Lord Walker and confirmed throughout: (1) ASSURANCE: the owner of the property must have made an assurance (or representation) to the claimant that they would acquire a right in or to the property. The assurance need not be express — it can be implied from words or conduct. In Thorner v Major [2009], the claimant's uncle made no explicit promise but his oblique comments and conduct over 29 years of unpaid farm work created a clear implied assurance that the nephew would inherit the farm. The assurance must be sufficiently clear and specific — not vague encouragement; (2) RELIANCE: the claimant must have relied on the assurance. Reliance is usually inferred from the assurance itself — if a clear assurance is made to the claimant, they are presumed to have relied on it unless the opposite is shown. The reliance need not be the only reason for the claimant's conduct — it is sufficient that the assurance played a significant part in the claimant's decision-making; (3) DETRIMENT: the claimant must have suffered detriment in reliance on the assurance. Detriment is assessed broadly: working for low or no wages; sacrificing career opportunities; making financial contributions to the property; spending years caring for the promisor; forgoing other relationships or opportunities. The detriment must make it unconscionable for the promisor (or their estate) to deny the claimant the interest promised.

The proprietary estoppel remedy is NOT automatic — the court does not simply give the claimant the full extent of the promise. Instead, the court satisfies the equity by awarding the minimum necessary to do justice: (1) THE MINIMUM EQUITY PRINCIPLE — Jennings v Rice [2002] EWCA Civ 159: the leading case on remedies. Robert Walker LJ (as he then was) set out the approach: the court should look at the EXPECTATION (what was promised) and the DETRIMENT (what was given up) and award a remedy that is proportionate and fair — the minimum equity. Where expectation and detriment are commensurate, the claimant may receive the full expectation. Where detriment is limited but expectation is very high, the remedy may be limited to reversing the detriment (or its monetary equivalent); (2) THE RANGE OF REMEDIES: the court has a wide discretion and can award: (a) the full expectation — transfer of the property as promised (most appropriate where assurance was clear, detriment was substantial, and the property is still available); (b) a lesser interest — a life interest in the property; a share; a right of occupation; (c) a money award — a lump sum compensating for the detriment suffered. In Jennings v Rice itself, a gardener/carer was awarded £200,000 (the value of the services provided) rather than the full estate of £1.285 million promised; (3) FACTORS THE COURT WEIGHS: (a) The clarity of the assurance — vague assurances attract lower remedies; (b) The extent and nature of the detriment — long unpaid service is significant; (c) Whether the property is still in the estate — if sold, a monetary equivalent; (d) The wishes of others affected — other family members' interests; (e) The length of time between assurance and enforcement; (f) Any change in circumstances — if the claimant's circumstances changed significantly; (4) THE COURT'S APPROACH IN FARMING CASES: where a nephew or child worked the family farm for decades on a clear promise of inheritance (following Thorner v Major), courts typically award the full expectation (transfer of the farm). The detriment (a working lifetime) is commensurate with the expectation (the farm).

The critical point is that proprietary estoppel operates AS AN EQUITY BINDING THE ESTATE — meaning it can prevail over the terms of a will: (1) THE EQUITY BINDS THE ESTATE: when the promisor dies, the proprietary estoppel equity does not die with them. The equity binds the estate — specifically, it binds the personal representative (executor/administrator) and the beneficiaries under the will (unless they are equity's darling — bona fide purchasers for value without notice, which beneficiaries under a will are not). The claimant can therefore bring a proprietary estoppel claim against the estate even if the will leaves the property to someone else entirely; (2) PROCESS — COMMENCING A CLAIM: a proprietary estoppel claim is brought in the Chancery Division of the High Court (or a county court if the estate value is below the jurisdictional threshold). It is a civil claim, not a probate claim. The claimant must commence proceedings before the limitation period expires. Limitation Act 1980 s.21 generally allows equitable claims within 6 years of the cause of action arising — though the cause of action arises when the equity is denied (on the promisor's death), so the claimant typically has 6 years from death; (3) INTERACTION WITH THE WILL — PRIORITY: if the proprietary estoppel claim succeeds, the court imposes a constructive trust or makes a direct transfer order over the property. The constructive trust (or transfer order) takes priority over the terms of the will — the beneficiary under the will who was meant to receive the property gets nothing (or reduced share) to the extent of the estoppel equity; (4) INTERACTION WITH INHERITANCE ACT CLAIMS (IPFDA 1975): a proprietary estoppel claim and an Inheritance Act 1975 claim can both be brought against the same estate but are separate causes of action. The Inheritance Act covers 'reasonable financial provision'; proprietary estoppel covers the specific promise. They may be pleaded alternatively. Key distinction: proprietary estoppel is based on a specific promise; IPFDA 1975 is based on need and the deceased's moral obligation; (5) DEFENDING AN ESTATE AGAINST A CLAIM: the executor should investigate any potential proprietary estoppel claims early. The executor can negotiate settlement or defend the claim. The cost of litigation is payable from the estate — another reason to make a will that addresses promises made during a lifetime.

Proprietary estoppel claims in the inheritance context tend to cluster in a handful of recognisable fact patterns: (1) THE FARMING CASE — most common pattern: an elderly farmer promises a nephew, son, or trusted farmhand that they will inherit the farm in exchange for years of low-paid or unpaid work. The farmer later changes the will (or dies without updating it) leaving the farm to a different relative. The worker claims proprietary estoppel. Thorner v Major [2009]: David Thorner worked his uncle Peter's farm for 29 years with no wages for the last decade. Peter made oblique references to David inheriting. Peter later changed his will and revoked the bequest to David — but then died without a new will. House of Lords: the assurances were sufficiently clear; the detriment was substantial; full expectation remedy — David received the farm; (2) THE CARER SCENARIO: a family member (often a child or sibling) is promised they will inherit the house or estate if they give up their own career/home to move in and care for the elderly person. The person dies without having updated the will (or the will was made before the caring arrangement and does not reflect the promise). Jennings v Rice [2002]: 14 years of increasingly intensive unpaid care; promise of the house and more; remedy £200,000 rather than full estate; (3) HOME IMPROVEMENT: a partner, cohabitant, or family member spends money improving property on the basis of promises of co-ownership or inheritance rights. The promisor dies and the improver has no legal interest. The improver claims proprietary estoppel in respect of their contributions; (4) BUSINESS SUCCESSION: a son or daughter is promised they will take over the family business if they work in it and forego other opportunities. The business is sold or left to another on death. Proprietary estoppel can apply to business assets as well as land; (5) THE REVOKED WILL: a will was made in the claimant's favour and later revoked (without the claimant knowing). The claimant continued to act in reliance on the original will. Revocation of a will does not automatically bar the proprietary estoppel claim — the equity arose from the assurance, not from the will.

The best way to avoid a proprietary estoppel claim disrupting your estate is prevention — addressing promises made during your lifetime in your will and associated arrangements: (1) KEEP YOUR WILL UP TO DATE: if you have made a promise to a family member or employee about inheriting your property, your will should reflect it. An up-to-date will that expressly fulfils the promise removes the basis for the claim (the promise has been kept). Conversely, a will that contradicts a promise invites a claim on death; (2) PUT BINDING ARRANGEMENTS IN PLACE DURING LIFETIME: if a farming arrangement, a care arrangement, or a business succession is intended, formalising it during the testator's lifetime is more reliable than leaving it to a will. Options: (a) a formal contract for sale at a favourable price during lifetime; (b) a gift of the property during lifetime (subject to CGT and IHT planning); (c) a binding partnership agreement or shareholders' agreement covering succession; (d) a formal tenancy or employment agreement with market value wages (avoiding the low-wage detrimental reliance argument); (3) DRAFT THE WILL WITH AWARENESS OF PROMISES: a properly drafted will should: (a) where the testator has made promises, include those promises as specific bequests with clear identification of the property; (b) include a recital of the circumstances if helpful (e.g. 'in recognition of John's work on the farm since 2005, I give him the farm'); (c) include a substitution clause in case the promised beneficiary predeceases; (4) AVOID AMBIGUOUS PROMISES: vague encouragement ('all this will be yours one day') creates evidential uncertainty — but courts are capable of finding sufficient assurance from circumstantial evidence (Thorner v Major). The farmer who says nothing but consistently behaves as if succession is agreed can create an implied assurance. Being clear — either making the promise expressly in the will or expressly revoking it — is better than ambiguity; (5) DOCUMENT WAGES AND PAYMENTS: if a family member works in the business or cares for a parent, ensuring they are properly paid at market rates removes the 'detriment' element of the estoppel claim. Payment at full market rate means there is nothing unpaid — no detrimental reliance.