Proprietary estoppel

Guest and another (Appellants) v Guest (Respondent) [2022] UKSC 27

The Authorities

14. The principles applicable to proprietary estoppel have never been before the Supreme Court, and only twice in recent times before the House of Lords, in Cobbe v Yeoman’s Row [2008] 1 WLR 1752 and Thorner v Major [2009] 1 WLR 776. Neither yields rich pickings for a reasoned understanding of the principles governing the identification of appropriate relief to satisfy the equity once established. Cobbe v Yeoman’s Row was primarily about whether proprietary estoppel had any role to play in an arms-length commercial subject to contract relationship where one party incurred expense on a speculation that a binding contract would eventually be entered into, but from which the other resiled. The claim failed in limine in the House of Lords, so that the question of appropriate remedy never arose. Besides containing the well-known dicta of Lord Walker of Gestingthorpe about the need for certainty in property transactions and the need for principle rather than uncontrolled judicial opinion as to the morality of the parties’ conduct, a bare recognition of the debate between detriment and expectation as the basis for relief, it offers nothing more by way of a solution.

15. The main significance of Thorner v Major was to rescue proprietary estoppel from what some commentators thought had been a fatal blow delivered to it by Cobbe. It displays strong similarity of type with the present case, since it was about the disappointed expectation that a farmer (“Peter”) would leave his farm on his death to the son of his cousin (“David”), on which David had worked full-time but for no payment for many years. The House of Lords restored the judge’s order that David should receive the whole of the farm, animal stock and equipment on the farmer’s death. There was no valuation of, or compensation for, David’s detriment, although the judge concluded that, without needing a precise valuation of the detriment, his expectation of inheriting the whole farm was not disproportionate to it. The decision may have rescued proprietary estoppel from an unintended early demise, but the House saw no need to reinvent it or recast the underlying principles as they had been developed by the courts of equity over more than a century.

16. If nothing else Thorner v Major demonstrates how factual differences within the same type of case may make all the difference to a perception about the justice of the outcome, and therefore the difficulty of laying down rules or principles applicable even to cases of a particular type, let alone across the wide field covered by proprietary estoppel. In particular there was no falling out between Peter and David. Peter had provided fully for David’s expectation in his will, but then destroyed it only because it also contained a legacy to someone else, of which he had repented. He was warned of the consequences of intestacy but died before making a new will, and David got nothing. The critical difference with the present case was that the time for fulfilment of the promise did not lie in the future at the time when David discovered that it had been repudiated. There were therefore no problems arising from early receipt and potential injustice to the promisor and his other dependants from the imposition of a clean break lifetime remedy which complicate the present case. Nonetheless both the expectation and the detriment were of very similar kinds to those in the present case. Yet the judge plainly started from a disposition to satisfy David’s expectation rather than calculate and then compensate for the detriment, and this was not criticised as an error of principle by the House of Lords. A “minimum equity” point was raised as a ground of appeal but not, as far as can be seen from the judgments, seriously argued.

17. There being no decisive treatment of the present issue by the highest court, the student is thrown upon the confused waters of a large body of non-binding but persuasive authority in the Court of Appeal and below, with the (in the event) less than compelling assistance of the parallel learning of other common law jurisdictions. The repeated judicial statements that they contain no conclusive resolution of the question which, of satisfying expectation or compensating for detriment, is the purposive bedrock of the equitable jurisdiction to grant appropriate relief does not mean that they can therefore just be passed by. As Floyd LJ said in the Court of Appeal, this may be because neither is.

18. It is instructive to look first at some of the antecedents to what is now called proprietary estoppel, since the jurisdiction did not suddenly spring up, fully fledged, in the 20th century. There are much earlier cases which, although sometimes classified under different legal headings, are based upon remarkably similar fact types. The first is illustrated by the attempted application in Loffus v Maw (1862) 3 Giff 592; 66 ER 544 of the principle laid down by the House of Lords in Hammersley v De Biel (1845) 12 Cl & F 45; 8 ER 1312 that where a person induces another to act upon the faith of a representation, then he will be compelled to make it good. The plaintiff was a young widow who was induced to care for the needs and home of an elderly and very unwell uncle for nothing more than pocket money by the promise that he would leave her specified interests in real property in his will, verified three years before his death, and on her threatening to leave, by her being showed a codicil to that effect. Sixteen days before he died he made a further codicil giving the same property to his son, cutting the plaintiff out altogether. The plaintiff claimed, in the alternative, the specific enforcement of the promise (i.e satisfaction of her expectation) or compensation by way of proper remuneration for all her work (i.e compensation for her detrimental reliance). Sir John Stuart VC gave her the former.

19. This early precursor of proprietary estoppel proved to be stillborn, because Loffus v Maw was overruled by the House of Lords in Maddison v Alderson (1883) 8 App Cas 467, on the ground that, in order to found a cause of action based on detrimental reliance, the representation in question had to be about an existing fact, not a promise of future conduct. The unsuccessful plaintiff had worked for many years without wages as housekeeper for Alderson, on the faith of a promise that he would leave her his house in his will, fortified by his showing her his signed but unfortunately not properly executed will to that effect. He therefore died intestate. The House of Lords considered whether the facts satisfied the doctrine of part performance, but held that her conduct was not sufficiently referable to a contract by Alderson to transfer his house to her. The case is best remembered as the classic exegesis of the (now abolished) equitable doctrine of part performance, under which the claimant’s right to the promised property lies not in the contract itself, which is void under the Statute of Frauds, but “upon the equities resulting from the acts done in execution of the contract” (per Lord Selborne at p 475). Those acts are generally a form of detrimental reliance, but the relief normally consists of fulfilment of the plaintiff’s expectation rather than compensation for her detriment.

20. The same single-minded determination to satisfy an equitable claim by reference to expectation rather than detriment is found in Dillwyn v Llewelyn (1862) 4 De G F & J 517, [1862] EWHC Ch J67, a case now widely regarded as an early precursor of proprietary estoppel, but treated by Lord Westbury LC as analogous to part-performance of an ineffective contract. A father invited his younger son to take a farm of his and build a house on it, producing a document of purported transfer which was ineffective for the purpose because it was neither a contract nor a deed. The son built a house on the farm for £14,000, following which his father died without ever perfecting his intended gift. His will did not provide for the plaintiff to inherit the farm. But the House of Lords satisfied the son’s equity, derived from his detrimental reliance, by an award of the fee simple, whereas the Court of Appeal had granted him only a life interest. The cost of the detriment was known to the last penny, but compensation for it did not form the basis of the remedy. Nor did it in the classic case about the doctrine of estoppel by acquiescence, in Lord Kingsdown’s famous dictum (while dissenting, but not on this point) in Ramsden v Dyson (1866) LR 1 HL 129, 170:

“If a man, under a verbal agreement with a landlord for a certain interest in land, or, what amounts to the same thing, under an expectation, created or encouraged by the landlord, that he shall have a certain interest, takes possession of such land, with the consent of the landlord, and upon the faith of such promise or expectation, with the knowledge of the landlord, and without objection by him, lays out money upon the land, a court of equity will compel the landlord to give effect to such promise or expectation.”

An alternative remedy consisting of refunding the money laid out did not even come a poor second.

21. Expectation was preferred to detriment again when Ramsden v Dyson, and Lord Kingsdown’s dictum, was applied by the Privy Council in Plimmer v Wellington Corpn (1884) 9 App Cas 699, but there was express recognition of the flexibility of the remedy, and of the alternative possibility of compensating for the detriment incurred in making expenditure on another’s land: see per Sir Arthur Hobhouse at pp. 713-714. He cited Unity Joint Stock Mutual Banking Corpn v King (1858) 25 Beav 72 as an example, where the landowner had not intended or suggested that the expenditure on the land by his sons should lead to the conferring of a proprietary interest upon them. They were declared to have a lien on the land for the recoupment of their expenditure upon it. This appears to be a case where there was no reasonable expectation greater than that to satisfy.

22. The early cases which deal with proprietary estoppel under its now customary name demonstrate a similar assumption that expectation is the main driver of the remedy. That is probably why it was thought fit to call the remedy a form of estoppel, even though a cause of action rather than merely a defence. The earliest of the well-known modern cases is Inwards v Baker [1965] 2 QB 29. A son was encouraged to build a bungalow on his father’s land, with the expectation that it should be his home for as long as he wished. After the father’s death his executors claimed to be able to terminate the son’s licence. The case was therefore a direct descendant of Dillwyn v Llewelyn, Ramsden v Dyson and Plimmer v Wellington, all of which were relied upon by both Lord Denning MR and Danckwerts LJ. It was the latter who called the remedy a form of equitable estoppel (at p 38). In his view the purpose of the remedy was to protect the promisee from injustice. But Denning MR was characteristically more specific. At p 37 he said:

“All that is necessary is that the licensee should, at the request or with the encouragement of the landlord, have spent the money in the expectation of being allowed to stay there. If so, the court will not allow that expectation to be defeated where it would be inequitable so to do.”

The son’s expectation was specifically enforced. He had been living rent free in the bungalow for 34 years by the time of the appeal and his father had paid half the £300 cost of its construction. There was nonetheless no attempt to evaluate and then compensate for the net continuing detriment (if any, because even at those days’ prices rent free occupation for over 30 years seems quite a good quid pro quo for the payment of £150), nor any suggestion that this was the purpose of the remedy. The recognition by the Court of Appeal that equity enjoyed a flexibility as to remedy was treated as enabling the best means to be provided for the fulfilment of the expectation.

23.  Lord Denning MR and Danckwerts LJ gave the leading judgments in the next case: E R Ives Investments Ltd v High [1967] 2 QB 379. This was factually distinct from those already discussed, since the detrimental reliance consisted of the defendant building a garage on his own land on the faith of an understanding, encouraged by his neighbour’s predecessor in title, that he enjoyed a right of way to it across his neighbour’s land. Unfortunately the supposed right of way was, in law, ineffective against the successor in title because of inter alia non-registration, although the successor had been informed about it at the time of purchase. It was a case of a genuinely defensive use of an estoppel or, as Lord Denning MR called it, at p 394, “equity arising out of acquiescence”. The remedy had by then been labelled proprietary estoppel by the editors of Snell’s Equity, 26th ed (1966), pp 629-633 and Danckwerts LJ was content to give that name the court’s first official blessing, at p 399. For present purposes all that needs to be noted (apart from Snell’s observation, at p 633, that “the doctrine thus displays equity at its most flexible”) is that again the promisee received specific enforcement of his expectation, and that there was no mention made of compensation for detriment.

24. Crabb v Arun District Council [1976] Ch 179 falls into much the same fact-set as Ives v High. The plaintiff, in the expectation encouraged by the defendant council that he would be given a right of access to his land over the defendant’s neighbouring land, sold off part of his land so as (to the defendant’s knowledge) to leave the retained part with no means of access other than by means of the expected easement. The defendant then blocked up the route of the expected easement leaving the plaintiff’s retained property landlocked. The plaintiff lost at first instance but duly received the expected easement by way of proprietary estoppel from the Court of Appeal, in which Lord Denning MR was joined by Lawton and Scarman LJJ. The case is memorable for Lord Denning’s robust but perhaps less than fully reasoned affirmation that proprietary estoppel can be used as a cause of action. At p 187 he said:

“When Mr Millett (later Lord Millett), for the plaintiff, said that he put his case on an estoppel, it shook me a little: because it is commonly supposed that estoppel is not itself a cause of action. But that is because there are estoppel and estoppel. Some do give rise to a cause of action. Some do not. In the species of estoppel called proprietary estoppel, it does give rise to a cause of action.”

Academic writers have been puzzling over that explanation ever since but it has stood the test of time. It is not in dispute, nor material to this appeal.

25. Much more important for present purposes is Scarman LJ’s famous observation about “minimum equity to do justice”, which now calls for serious examination. Fortunately the case is very fully reported. In opening the appeal Mr Millett QC made it clear that his client’s expectation was not that the easement would be provided for nothing in return. Rather he submitted that the loss sustained by having his land sterilised by being landlocked for a time (in fact for five or six years) should be set off to the extinction of any requirement for payment for the easement: see pp181-182. Lord Denning accepted that submission in terms, at p.189-190. Scarman LJ did so as well, but in more detail, at pp. 198-199. The basis of the analysis, both in Mr Millett’s submission and in the judgments of Lord Denning and Scarman LJ, was how best and most fairly to fulfil, but not to exceed, the plaintiff’s expectation. It had nothing at all to do with compensating for the detriment as an alternative to fulfilling the expectation, still less choosing in any particular case the cheaper (or more minimalist) alternative, as between the two. The true “detriment” in that case was the sale-off by the plaintiff of part of his land in a way which left the remainder landlocked without the promised easement. The true harm caused by the defendant’s repudiation was not a few years’ obstruction of an easement to which in equity the plaintiff was already entitled (which was the subject of the set-off) but the permanent sterilisation of part of the plaintiff’s land by the denial of the easement in perpetuity. That was not itself valued, and the remedy awarded was specific enforcement of the expectation, not compensation for the detriment or harm. Lord Scarman’s “minimum equity” dictum appears in the following passage, at pp. 198-199:

“I turn now to the other two questions-the extent of the equity and the relief needed to satisfy it. There being no grant, no enforceable contract, no licence, I would analyse the minimum equity to do justice to the plaintiff as a right either to an easement or to a licence upon terms to be agreed. I do not think it is necessary to go further than that. Of course, going that far would support the equitable remedy of injunction which is sought in this action. If there is no agreement as to terms, if agreement fails to be obtained, the court can, in my judgment, and must, determine in these proceedings upon what terms the plaintiff should be put to enable him to have the benefit of the equitable right which he is held to have.”

This analysis is all about fine-tuning the fulfilment of the expectation of the promisee, and nothing to do with valuing and then compensating for the detriment, while denying him the expectation.

26. This expectation-based approach is hardly surprising. The authorities to which the Court of Appeal had regard included Ramsden v Dyson, Plimmer v Wellington, Inwards v Baker and Ives v High. As I have sought to demonstrate, they are almost single-minded in their pursuit of the enforcement of expectation. None of them would have given Scarman LJ any inkling that compensating for the detriment, as an alternative to satisfying or enforcing the expectation, had anything to do with the remedy of proprietary estoppel. Nor, for completeness, would Duke of Beaufort v Patrick (1853) 17 Beav 60, to which Scarman LJ referred during argument at p 182. Attempts since then to use “minimum equity” as a sort of mantra for that purpose are in my view misconceived, and would have left that distinguished judge very surprised at such misuse.

27. The earliest case of compensation for detriment as a remedy by way of proprietary estoppel which I have found appears to be Dodsworth v Dodsworth (1973) 228 EG 1115. The plaintiff persuaded her brother and his wife (who had just returned from Australia and were looking for somewhere to live) to come and live with her in her bungalow on the basis that they could use it as their home for as long as they wanted. They spent about £700 on improvements. The cohabitation lasted only a few months, after which the parties fell out and the plaintiff sued them for possession. The County Court judge held that an equity had been established but, because the specific enforcement of the defendants’ expectation would force then to live with the plaintiff under the same roof while they were at loggerheads, a more just solution would be to order the plaintiff to refund their expenditure, so that they could use it on another property. The defendants appealed and the plaintiff then died. The Court of Appeal also considered them entitled to an equity, and recognised that the obstacle which had prevented the judge from fulfilling their expectations had disappeared on the plaintiff’s death. But the court held that the conferral on the defendants of a life interest would make them tenants for life under the Settled Land Act 1925 which would give them statutory powers (including a power of sale) which far exceeded their expectations. So they were given a right to possession until repaid their outlay. This was not because compensation for detriment was regarded as the purpose of the remedy, but only because the court thought that an expectation-based remedy could not be awarded in a way which would not have been in excess of their real expectation.

28. The same problem arose in Griffiths v Williams (1977) 248 EG 947, but with an outcome that fully vindicated the promisee’s expectation. Mrs Williams had lived for many years in a house belonging to her mother, in the expectation encouraged by her mother that she would inherit a life interest in it. Her mother had so provided in a will, and Mrs Williams has spent about £2,000 on the house, partly in running repairs and partly in improvements. Her mother then changed her will, cutting out Mrs Williams altogether. After her mother’s death Mrs Williams was sued for possession. Reginald Goff LJ asked, at p 948:

“What is the equity? That must be an equity to have made good, so far as may fairly be done between the parties, the representation that Mrs Williams should be entitled to live in the house rent-free for the rest of her life”

He then (with the parties’ consent) neatly avoided the Settled Land Act problem by providing for her to have a long lease at a nominal rent determinable on her death. But he made this comment, at p949, about the Dodsworth case:

“But it seems to me that Dodsworth v Dodsworth proceeded upon the basis which I have spelt out of Crabb’s case - that the third problem (i.e. remedy) is one of discretion: the court ought to see, having regard to all the circumstances, what is the best and fairest way to secure protection for the person who has been misled by the representations made to him and subsequently repudiated”

For my part I would readily accept that the remedy is discretionary, but “the best and fairest way to secure protection” for the promisee begs the question: protection from what? Crabb’s case is clear authority for an expectation-based form of protection, at least as a starting point.

29. A dispassionate observer of those two cases might think that the real distinction between them (once the plaintiff in Dodsworth had died) lay not so much in the ability of the Court of Appeal in Griffiths to navigate a safer route around the Settled Land Act, but in the very large difference in the period during which the promisees relied on the promises made. It goes far beyond the idiosyncrasies of particular judges to regard reliance during the best part of the promisee’s working life as creating a much stronger case for the fulfilment of expectation than a few months spent as a lodger on return from abroad. If there is some kind of spectrum between expectation and detriment as the basis for relief based upon the length of the period of detrimental reliance, then the length of that period in the present case must surely lie at the expectation end of the spectrum.

30. Pascoe v Turner [1979] 1 WLR 431 is the first of the cases cited in this appeal in which Scarman LJ’s “minimum equity to do justice” dictum appears to have been elevated into a guiding principle. It is a direct descendent of Dillwyn v Llewelyn, and the outcome was the same. The plaintiff and the defendant lived together as man and wife in a house bought by the plaintiff. When their relationship was breaking down due to the plaintiff’s infidelity he assured the defendant that the house was hers and everything in it. She then spent sums on improvements which were objectively modest but substantial for her. He had by then left but, later, sued her for possession. The Court of Appeal awarded her the house outright, together with the contents, by way of remedy for proprietary estoppel. It was a full specific enforcement of her expectation and rejected her alternative lesser claim for a life interest. After reviewing the authorities from Dillwyn v Llewelyn to Crabb v Arun Cumming-Bruce LJ said this, at pp 437- 438:

“So the principle to be applied is that the court should consider all the circumstances, and the counterclaimant having at law no perfected gift or licence other than a licence revocable at will, the court must decide what is the minimum equity to do justice to her having regard to the way in which she changed her position for the worse by reason of the acquiescence and encouragement of the legal owner.”

It is clear from the court’s review of her detrimental reliance that the award in her favour was worth more by many orders of magnitude than any value which could have been placed upon her detriment. Indeed the court regarded a life interest or outright ownership as the only real alternatives and gave heavily fact-dependent reasons for preferring the latter, even though it was of course worth much more than the former. It is certainly a good example of the discretionary approach to a remedy designed primarily to satisfy expectation, and a clear demonstration that, even using the “minimum equity to do justice” dictum as a principle, (which in my view it was not intended to be) “minimum” plainly does not mean cheapest.

31.  It is therefore not at all surprising to find, three years later, one of the greatest equity judges, Oliver J (later Lord Oliver of Aylmerton) treating as uncontroversial the following summary by counsel of the remedy of proprietary estoppel in the following terms, in Taylors Fashions Ltd v Liverpool Victoria Trustees Co. Limited [1982] QB 133, at 144:

“if under an expectation created or encouraged by B that A shall have a certain interest in land, thereafter, on the faith of such expectation and with the knowledge of B and without objection by him, [A] acts to his detriment in connection with such land, a Court of Equity will compel B to give effect to such expectation.” (my italics).

This found its way into the 31st Edition (2005) of Snell’s Equity, at para 10-16, as “the most important and authoritative modern statement of the doctrine” subject to a health warning about the need for the remedy to be proportionate to the detriment, and satisfaction of the expectation not being an invariable requirement. That summary was duly adopted as his guidance by the deputy judge Mr John Randall QC at first instance in Thorner v Major [2008] WTLR 155, para 5, and his judgment was eventually upheld by the House of Lords.

32. Another case in which there was a need to avoid forcing warring parties into cohabitation was Burrows v Sharp (1991) 23 HLR 82. The appellant, a long-term council tenant, had managed to exercise her right to buy the freehold of her house by securing the financial assistance of her grand-daughter and her husband (the respondents) on the basis that they would pay the necessary mortgage and look after the appellant’s handicapped daughter after the appellant’s death, and inherit the house. They also planned to extend the house and moved in with their children to live with the appellant and her daughter. The extension had not been built by the time the relationship broke down within a year of the move, not least because of the serious overcrowding involved. The County Court judge made what the Court of Appeal described as a complicated but wholly unworkable order which sought to provide for their continued cohabitation. In the end, after a detailed analysis of the insuperable obstacles in the way of satisfying the respondents’ expectations, and a review of Crabb, Dodsworth and Griffiths, Dillon LJ made an order for refunding the respondents’ expenditure. They had fortunately not parted with their own council flat, to which they were able to return. So they were not left homeless. He summarised the very difficult remedial task in this way, at p 92:

“It is often appropriate to satisfy the equity by granting the claimant the interest he or she was intended to have. If that is not practicable however, the court has to do the best it can. In general it would, if possible, want to avoid giving the claimant more than he was ever intended to have.”

That case illustrates a number of the problems which have led the court to depart from specific enforcement of the promised expectation. They included the need to avoid enforced cohabitation, in the present case called the need for a clean break, the fact that the promise had been repudiated well before the benefit was to be conferred (on the appellant’s death) and the very short period during which the reliant conduct had occurred. It was also relevant that the reliant respondents had not burned their boats, and could return to their own flat. But the problems do not have appeared to have included a concern that the expectation was disproportionate to the detriment. It almost certainly was, but that was not treated as an obstacle to an expectation-based remedy. Still less was compensating for the detriment treated as the aim of the equitable remedy.

33. The order of the Court of Appeal in Baker v Baker (1993) 25 HLR 408 is sometimes regarded as an example of a detriment-based remedy. In fact it was the opposite. The plaintiff was a 75 year old man who contributed £33,950 to the purchase of a house for his son and daughter-in-law, on the basis that he would be given a room there in which to live for the rest of his life. The relationship failed within a year, and the plaintiff moved into council accommodation. The trial judge rejected his claim to a resulting trust interest but ordered repayment of his outlay as a remedy for proprietary estoppel. The defendants appealed on the basis that this was much more than his expectation interest was worth. Agreeing, the Court of Appeal ordered his expectation interest to be valued and paid, by a majority ruling that there should be no discount for the fact that the plaintiff had found somewhere else to live at public expense. No one suggested that the parties could be expected to continue to live together. It was therefore a case in which the promisee received a monetary proxy for his expectation interest. There is a useful analysis by Beldam LJ at p 415 of the “minimum equity to do justice” dictum in Crabb, in which he concludes:

“I would not interpret Lord Scarman's remarks as suggesting that in a case in which a plaintiff's equity could only be satisfied by a monetary award, that the court necessarily had to place the minimum value on the disappointed interest.”

Thus the reduction in the plaintiff’s monetary remedy was not because expectation was, in that case, cheaper than compensation for detriment, but because the expectation was the true and maximum measure of the equity.

34. The penultimate 20th Century English authority to which I need to refer is Walton v Walton (unreported) 14 April 1994. It is a farming case with considerable similarities with the present, at a high level of generality. The promise by mother to son was that the son would inherit her farm. It was first made when he was a teenager, and he devoted many years labour to the farm at very low wages before the mother retired. The main differences, which made the question as to remedy much easier than here, are that although the mother and son had fallen out during her lifetime she had died by the time of the trial, and there was no other family member with relevant expectations in relation to the farm which had been promised to the son. There were, in short, none of the obstacles in the way of the full expectation-based remedy ordered by the Court of Appeal of the type which make the present case so difficult. The case is of value because of the brief statement of principle about the purpose of the remedy by Hoffmann LJ. At para 11 he said:

“The plaintiff’s claim is based upon equitable estoppel. That sounds very technical but the principle is really quite simple. Ordinarily the law does not enforce promises unless they have been made formally under seal or as part of a contract. Mrs Walton’s promise was not, of course, made under seal and for reasons which I shall explain in a moment, I do not think that it was part of a contract. So if there was nothing more than the promise, she would have been free to change her mind. It would have been a matter for her conscience and not the law. But the position is different if the person who has been promised some interest in property has, in reliance upon it, incurred expense or made sacrifices which he would not otherwise have made. In such a case the law will provide a remedy. It can take various forms. It may order the maker of the promise to pay compensation for the expense which has been incurred. It may make payment of compensation a charge on the property. Or it may require the promise to be kept. The choice of remedy is flexible. The principle on

which the remedy is given is equitable estoppel. As Oliver J put it in Taylor Fashions Ltd. v Liverpool Trustee Co. Ltd [1982] QB 133, 151, [1981] 1 All ER 897, the question is -

‘whether, in particular individual circumstances, it would be unconscionable for a party to be permitted to deny that which, knowingly or unknowingly, he has allowed or encouraged another to assume to his detriment.’”

In the event the court ordered the mother’s executors to keep her promise in full. There was no attempt to value either the expectation or the detriment, still less to choose the cheaper as the “minimum equity”.

35. In Sledmore v Dalby (1996) 72 P & CR 196, [1996] EWCA Civ 1305 Mr and Mrs Sledmore allowed their daughter Jacqueline and her husband Mr Dalby use of an unoccupied house which they owned, initially at a modest rent but, after Mr Dalby lost his job and Jacqueline contracted cancer, rent-free, and on the basis that it would one day be theirs by inheritance. The Dalbys then spent a significant amount on improvements. Mr Sledmore did make a will leaving the property to Jacqueline if she survived her mother, but she did not. After Mr Sledmore died, his widow sought possession of the house for her own use, her existing home being precarious due to disrepair and a large mortgage. By that time Mr Dalby had little use for the property, spending two nights there a week and living mainly with a new partner at her home, while again employed. But he successfully resisted the possession claim at first instance, on the basis of proprietary estoppel.

36. The Court of Appeal ordered him to leave. The court was palpably offended at the injustice of his conduct in insisting upon his supposed equity at a time when he hardly needed the property while his mother-in-law, in straightened circumstances, plainly did. Roche LJ (with whom Butler Sloss LJ agreed) held that Mr Dalby had to be content with something less than his full expectations, that his equity had expired and that in the changed circumstances there was nothing unconscionable in Mrs Sledmore seeking possession. While agreeing, Hobhouse LJ also made reference to recent dicta from Australia (to which I will return) in support of an additional conclusion about the need for proportionality between the remedy and the detriment. He said at p 209 that:

“This is to say little more than that the end result must be a just one having regard to the assumption made by the party asserting the estoppel and the detriment which he has experienced.”

37. This decision seems to me, on its facts, to have been a very proper application of the fundamental principle of unconscionability, and at the correct time, namely when the promisor seeks to repudiate the promise. The facts of the case show vividly that it will not always by then be unconscionable to do so. But the introduction of a supposed general requirement for proportionality between the remedy and the detriment was entirely new in English law. Although not part of the ratio of Sledmore v Dalby, it soon proved to be a fast-growing seed. The irony is that, as will appear, it did not flourish in its country of origin.

38. From the beginning of the current century the cases come thick and fast, as do the academic writings. I intend to consider seven of the cases, as appearing to be the most relevant to the present task. But it is first worth pausing to see what a distinguished academic, Professor Elizabeth Cooke, thought was the animating principle or aim behind the choice of remedy, in England at least, in her book The Modern law of Estoppel (2000). Her view was that despite the dicta in Australia relied upon by Hobhouse LJ in Sledmore v Dalby (to which I shall return) the long-standing tendency of the English courts had been to frame relief on an expectation rather than detriment basis, save where practical considerations made that impossible, impracticable or manifestly unjust. An expectation-based remedy would typically be specific enforcement of the promise, but it might take the form of a monetary equivalent, for example where the promised property had already been sold, as in Wayling v Jones (1995) 69 P & CR 170. My own examination of the pre 2000 authorities leads me to the same conclusion.

39. Gillett v Holt [2001] Ch 210 marks the arrival on the scene of England’s most significant living judicial contributor to this debate, Lord Walker of Gestingthorpe, then Robert Walker LJ. It was a farming case in which a wealthy landowner Mr Holt took the plaintiff (who was not a family member) under his wing in his mid-teens, trained him to be the resident manager of his farm and later encouraged him to expect that he would inherit it. They fell out after the plaintiff had lived and worked there for over 25 years, and Mr Holt sought to dismiss and remove him, also cutting him out of his will. As in the present case the litigation was fought while Mr Holt remained alive, and while therefore the plaintiff’s proprietary expectation of inheritance remained in the future. But there was no problem of cohabitation at the farm, since Mr Holt had long since ceased to live or work there. The plaintiff failed at trial on promise and detriment but succeeded in the Court of Appeal. In relation to detriment his success was significantly based on what Robert Walker LJ said was the judge having taken a “too narrowly financial a view of the requirement for detriment” (p 235). In the event the plaintiff received an expectation-based award, consisting of a mixture of the freehold farmhouse, freehold farmland and monetary compensation for his expectation interest in the remainder of the farming business, in that aspect to achieve a clean break with Mr Holt and his new protegee. There does not appear to have been any attempt to monetarise the detriment, to consider whether it was proportional to the expectation, or to frame a detriment-based remedy.

40. The treatment of the remedy issues is too fact (and tax) specific to yield much express dicta about the underlying principles, but Robert Walker LJ did refer to the need to consider all the circumstances, and to the “minimum equity to do justice” dictum in Crabb. He also introduced his analysis of proprietary estoppel with this summary, at p 225:

“…the fundamental principle that equity is concerned to prevent unconscionable conduct permeates all the elements of the doctrine. In the end the court must look at the matter in the round.”

All in all Gillett v Holt represents no departure from the tendency of the English courts to prioritise an expectation-based approach to remedy, as firmly established by the turn of the century, over the previous century and a half.

41. The same cannot be said of Jennings v Rice [2003] 1 P&CR 8, [2002] EWCA Civ 159. This was a classic “one day all this will be yours” case, in which the claimant looked after an elderly widow Mrs Royle on what became an unpaid basis, as a live-in carer tending for her every need, all in the expectation which she encouraged that he would inherit all or part of her large house valued on her death at £420,000 and its furniture, worth £15,000. The judge awarded him £200,000, on the basis that he needed only £150,000 to buy himself a suitable house, and that the sum awarded was a fair estimate of the cost of full-time nursing care for the relevant period.

42. The claimant appealed, unsuccessfully, on the ground that the basic rule was that a proprietary estoppel equity could only be satisfied by making good the expectation. After a review of the authorities, including Sledmore v Dalby, Aldous LJ said, at para 36:

“There is a clear line of authority from at least Crabb to the present day which establishes that once the elements of proprietary estoppel are established an equity arises. The value of that equity will depend upon all the circumstances including the expectation and the detriment. The task of the court is to do justice. The most essential requirement is that there must be proportionality between the expectation and the detriment.”

On the way to that conclusion he nonetheless rejected, as forming any part of English law, the notion that compensating for the detriment was the aim or purpose of the award: see para 30. I must confess to some surprise that proportionality between remedy and detriment should have been regarded by Aldous LJ as “the most essential requirement” in the framing of the remedy. It had never previously been so described, during the more than 150 years during which, on broadly comparable facts, the courts of equity had been applying and developing this essentially flexible jurisdiction. And the only prior English recognition of it was in the concurring judgment of Hobhouse LJ in Sledmore v Darby which did not form part of the ratio of the case, borrowed from Australian obiter dicta which advocated a different point (namely that the aim of the remedy is to protect against detriment) and which have not stood the test of time, even in Australia.

43. Robert Walker LJ agreed but added his own analysis. At para 44 he said:

“The need to search for the right principles cannot be avoided. But it is unlikely to be a short or simple search, because (as appears from both the English and the Australian authorities) proprietary estoppel can apply in a wide variety of factual situations, and any summary formula is likely to prove to be an over-simplification. The cases show a wide range of variation in both of the main elements, that is the quality of the assurances which give rise to the claimant’s expectations and the extent of the claimant’s detrimental reliance on the assurances. The doctrine applies only if these elements, in combination, make it unconscionable for the person giving the assurances (whom I will call the benefactor, although that may not always be an appropriate label) to go back on them.”

Turning to the remedy he continued (from para 45) with an analysis of the distinction between, on the one hand, an understanding little short of contract in which the expectation and the detriment have been clearly defined, where a full expectation-based remedy would usually be appropriate and, on the other hand, a case where the expectation is genuine but not clear, where the fulfilment of the highest expression of it may only be a starting point. In a later lecture he said that he would have preferred to use the concept of a spectrum between those extremes. Speaking of the “minimum equity to do justice” dictum in Crabb, he said, at para 48:

“Scarman LJ’s reference to the minimum does not require the court to be constitutionally parsimonious, but it does implicitly recognise that the court must also do justice to the defendant.”

He concluded at paras 50-51:

“ To recapitulate: there is a category of case in which the benefactor and the claimant have reached a mutual understanding which is in reasonably clear terms but does not amount to a contract. I have already referred to the typical case of a carer who has the expectation of coming into the benefactor’s house, either outright or for life. In such a case the court’s natural response is to fulfil the claimant’s expectations. But if the claimant’s expectations are uncertain, or extravagant, or out of all proportion to the detriment which the claimant has suffered, the court can and should recognise that the claimant’s equity should be satisfied in another (and generally more limited) way.

But that does not mean that the court should in such a case abandon expectations completely, and look to the detriment suffered by the claimant as defining the appropriate measure of relief. Indeed in many cases the detriment may be even more difficult to quantify, in financial terms, than the claimant’s expectations.” (my italics).

44. Robert Walker LJ deprecated any detailed computational approach to valuing the detriment. After illustrating an Australian example, he continued, at para 54:

“That illustrates the Australian preference for compensating the reliance loss only. Under English law that approach may sometimes be appropriate (see paragraph 51 above) but only where, on the facts, a higher measure would amount to overcompensation. In my view it would rarely if ever be appropriate to go into detailed inquiries as to hours and hourly rates where the claim was based on proprietary estoppel (rather than a restitutionary claim for services which were not gratuitous). But the going rate for live-in carers can provide a useful cross-check in the exercise of the court’s discretion.”

Finally at para 56 he said this about proportionality:

“The essence of the doctrine of proprietary estoppel is to do what is necessary to avoid an unconscionable result, and a disproportionate remedy cannot be the right way of going about that.”

No one would disagree with the notion that a remedy must be proportionate to the harm. But in the present context that begs the question whether the harm is the detriment or rather (as I think) the loss flowing from the repudiation of the expectation. Nonetheless by that means the seed of proportionality has become firmly embedded in the English law of proprietary estoppel.

45. Ottey v Grundy [2003] EWCA Civ 1176; [2003] WTLR 1253 is an example of a case in which the proportionality principle (by then binding as part of the ratio in Jennings v Rice) was applied in the framing of a remedy. The claimant had cared for a Mr Andreae during a loving relationship of three years’ duration, but promises that she would inherit his apartment in Jamaica and house-boat on the Thames were made only two years before they broke up. Mr Andreae died about a year later. The trial judge awarded the claimant the Jamaica flat (with £50,000 in lieu) plus another £50,000 out of an expectation which he valued at £250,000. He found, without valuing the detriment but noting its short duration, that the expectation and the detriment were out of proportion. The main issue in the appeal was whether the claimant should have received anything, but she cross-appealed for a larger share of her expectations. Both the appeal and the cross-appeal failed.

46. Giving the leading judgment Arden LJ said at para 58 that Robert Walker LJ’s judgment in Jennings v Rice did not detract “from the general proposition that the relationship between the promise and the remedy must be proportionate, and that the promise, even if of a specific property, is only a starting point”. At para 61 she said that:

“…the purpose of proprietary estoppel is not to enforce an obligation which does not amount to a contract nor yet to reverse the detriment which the claimant has suffered but to grant an appropriate remedy in respect of the unconscionable conduct.”

47. In my view the outstanding feature of Ottey v Grundy was the shortness of the period of detrimental reliance, not in absolute terms, but by comparison with what must have been the expectations of both parties at the time when the promise was made. Any promise to provide by inheritance suggests an assumption that, in the meantime, the relationship will continue at least for the life of the promisor. In that case the judge found that the relationship was a close, devoted and loving one on both sides, so that its early failure was outwith their contemplation when the promise was made, at a time when Mr Andreae was only in his early 50s. It is easy to see why, in such a case, there may be nothing unconscionable in the promisee receiving less than her full expectation.

48. Uglow v Uglow [2004] EWCA Civ 987; [2004] WTLR 1183 is another farming case. Nothing turns on the facts, and the estoppel claim failed both at first instance and on appeal. But it is noteworthy for the characteristically useful and compressed six point summary of the relevant principles provided by Mummery LJ at para 9. They are well-known and need not be set out in full. In points (1),(2),(4) and (5) he emphasises how the prevention of unconscionable conduct lies at the heart of the doctrine. Point (5) is directed at remedy:

“It is necessary to stand back and look at the claim in the round in order to decide whether the conduct of the testator had given rise to an estoppel and, if so, what is the minimum equity necessary to do justice to the claimant and to avoid an unconscionable or disproportionate result.”

It is to be noted that, while endorsing proportionality of result as a relevant consideration, he does not tie the remedy to the detriment as the subject of a proportionality test, still less suggest that the aim of the remedy is to protect against detriment.

49. Henry v Henry [2010] 1 All ER 988, an appeal from St Lucia, is famous for the dictum at para 65 that:

“Proportionality lies at the heart of the doctrine of proprietary estoppel and permeates its every application.”

Geraldine Pierre had promised Calixtus Henry that he would inherit her one-half share of a property in St Lucia if he cared for her until her death and cultivated the plot. But Theresa Henry purchased Geraldine’s share before she died. The Court of Appeal held that since Calixtus had been in occupation at the time of the sale his estoppel equity was an overriding interest, and therefore bound Theresa. He therefore received his half share. On Theresa’s appeal the Privy Council cut his entitlement by half. He had suffered a detriment in providing food and care for Geraldine, and had, by remaining on the plot, admittedly rent free and partly for his own benefit, deprived himself of the opportunity of a better life elsewhere. The Court of Appeal had held that it had no power to consider whether the promise (and the resulting benefit) was disproportionate to the detriment. This is what led to the dictum to the contrary quoted above. The outcome is a slightly strange one, in the sense that the Board made no apparent attempt to value either the expectation or the detriment, and simply made an unexplained 50% reduction in an otherwise expectation-based specific enforcement of the promise. It no doubt satisfied the Board’s perception as to what needed to be done to rectify the unconscionability of Calixtus being otherwise left with nothing. It is difficult to dispel the suspicion that sympathy for Theresa, who had paid for Geraldine’s share of the property in good faith, may have led to a conclusion that, as between her and Calixtus, the pain should fairly be equally shared.

50. The next relevant case is Davies v Davies [2016] EWCA Civ 463; [2016] 2 P & CR 10, again arising from an expectation of inheriting a farm. Although heavily caveated, it comes nearer to elevating compensation for detriment into a governing principle in the framing of a remedy than any other. At para 39, shorn of references to authority and academic scholarship, Lewison LJ said this:

“There is a lively controversy about the essential aim of the exercise of this broad judgmental discretion. One line of authority takes the view that the essential aim of the discretion is to give effect to the claimant’s expectation unless it would be disproportionate to do so. The other takes the view that essential aim of the discretion is to ensure that the claimant’s reliance interest is protected, so that she is compensated for such detriment as she has suffered. The two approaches, in their starkest form, are fundamentally different. Much scholarly opinion favours the second approach. Others argue that the outcome will reflect both the expectation and the reliance interest and that it will normally be somewhere between the two. Logically, there is much to be said for the second approach. Since the essence of proprietary estoppel is the combination of expectation and detriment, if either is absent the claim must fail. If, therefore, the detriment can be fairly quantified and a claimant receives full compensation for that detriment, that compensation ought, in principle, to remove the foundation of the claim. Fortunately, I do not think that we are required to resolve this controversy on this appeal.”

51. On the facts, the claimant had not made life-changing choices in reliance upon any promise of inheritance. Lewison LJ acknowledged that, in such a case, the imponderable and speculative nature of the detriment might properly lead the court to decide that specific enforcement of the expectation in specie should be given: see para 66. The outcome of a complicated set of facts was a largely unexplained very round sum, between the defendants’ detriment-based offer and the judge’s detriment coupled with expectation-based financial proxy, which provides no real insight into the Court of Appeal’s precise analysis.

52. The well-known passage about the ‘lively controversy’ quoted above calls for some cautious examination. First, while there clearly was, by 2016, a long line of authority stretching back over 150 years which had generally followed the expectation-based approach, there is not a single English authority favouring the approach that the essential aim of the remedy was to protect the claimant’s reliance interest and therefore to compensate for the detriment. As I have sought to show, the nearest that the English authorities had come was to say that there had to be some proportionality between remedy and detriment, but always a rejection of the notion that compensation for the detriment was the aim. There was some short-lived Australian authority apparently to the contrary, to which I will shortly turn.

53. Secondly, the supposed logic of the detriment-based approach is in my view both faulty in origin and wrong in its inevitable result. It is faulty in origin because it fails to recognise that while reliant detriment is necessary to engage the equitable relief, and forms a large part of its moral justification, it is the repudiation of the promised expectation which constitutes the unconscionable wrong. It ignores the view of equity that land is unique, which is the foundation for the remedy of specific performance, and for much of the remedial work of equity in supplementing the defective notion of the common law that every wrong can and must be remedied by monetary compensation. It mistakenly treats the detriment rather than the loss of expectation as the relevant harm. It is wrong in its result because it would if correct entirely replace what is meant to be a flexible conscience-based discretion aimed at producing justice with the mechanical task of monetarising the detriment and the expectation and then awarding whichever produces the lower figure, on the misconceived basis that this is the “minimum equity needed to do justice”. It would banish the expectation-based remedy to the diminishing shadowy margins where the court could not satisfy itself as to one or other of those two figures. This would set the traditional English approach, that the purpose of the estoppel is, prima facie, to hold the promisor to his promise, completely upon its head. It is in that context not surprising that its proponents question whether proprietary estoppel is the right name for the remedy at all. It would directly contradict the warning from Robert Walker LJ in Jennings v Rice that it would hardly, if ever, be appropriate to undertake a precise mathematical task of calculating the monetary value of the detriment. And it would make a nonsense of proportionality. If the aim of the remedy is to compensate for the detriment, why should it not do so precisely?

54. I must mention the recent decision of the Court of Appeal in Habberfield v Habberfield [2019] EWCA Civ 890. The facts were similar to those of the present appeal. The claimant was assured that she would inherit a sufficient part of her parents’ farmland on which to run a viable dairy unit, and in reliance she spent nearly 30 years working there at low wages with minimal holidays. At the time when the promise was repudiated her mother was still alive and living in the farmhouse. The judge (Birss J) made a monetary award based on a valuation of most of her expectation, of about £1.17 million, on a basis which maximised the prospects of the mother being able to continue to live at the farmhouse which, although within the claimant’s expectation by way of inheritance, was excluded from the valuation. The award was also scaled down from her full expectation by reference to the claimant’s earlier rejection of an offer from her parents which would have preserved a working dairy unit on the farm, with a replacement value of £400,000. The detriment consisting of wage differential was about £220,000.

55. The Court of Appeal upheld the judge’s approach. In particular Lewison LJ agreed with the judge’s view that the “whole life” consequences of the promises to the claimant made it impossible fairly to value her detriment as a whole, so that it could not be shown that his proposed award was out of all proportion to her detriment. He affirmed the relevance of Robert Walker LJ’s spectrum, and treated the case as lying towards its quasi-contractual end. The claimant had done what her parents had asked of her, and they should now perform their promise. At para 33 he said:

“Underpinning the whole doctrine of proprietary estoppel is the idea that promises should be kept. “

Later at para 68 he said:

“Both Mr Wilson and Mr Blohm agreed (rightly in my judgment) that there was no clear point of division between different categories of proprietary estoppel claims. There was a broad spectrum of such claims. Looking back from the moment when assurances are repudiated, the nearer the overall outcome comes to the expected reciprocal performance of requested acts in return for the assurance, the stronger will be the case for an award based on or approximating to the expectation interest created by the assurance. That does no more than to recognise party autonomy to decide for themselves what a proportionate reward would be for the contemplated detriment. As Mr Blohm put it: if you get what you asked for, you should give what you offered.”

The Australian jurisprudence

56. The fons et origo of the Australian jurisprudence to the effect that the aim of all estoppels is to prevent harm arising from detrimental reliance are the minority opinions of members of the High Court, dissenting, in Commonwealth of Australia v Verwayen (1990) 170 CLR 394. The case arose from the dreadful collision in 1964 between two Australian Navy warships, in which the aircraft carrier HMAS Melbourne cut in two and sank the destroyer HMAS Voyager, with heavy loss of life. The plaintiff had been a member of Voyager’s crew, injured in the collision. He alleged negligence and, at that time in accordance with policy, the defendant did not deny either a duty of care or plead limitation, following which the plaintiff continued with the action and incurred cost. Later, upon a change in litigation policy, the defendant sought to plead both defences by amendment. It succeeded in obtaining leave to amend to run both defences at first instance, was held to have been estopped from doing so in the Court of Appeal, and lost its appeal to the High Court by a bare 4-3 majority. Two of the majority upheld estoppel while the other two based their conclusion on waiver. The result was that the plaintiff’s expectation of not having to face either of those defences was protected. His only detriment was probably costs.

57. There are influential dicta from the minority (Mason CJ, Brennan and McHugh JJ) that protection from detriment is the main aim of the court’s remedy for estoppel, and that the “minimum equity” may not require specific enforcement of the promise or representation. But the estoppel in question was not proprietary estoppel, nor had it been in the earlier case of Grundt v Great Boulder Pty Gold Mines Ltd (1937) 59 CLR 641, from which, in part, the minority developed their thesis.

58. Giumelli v Giumelli [1999] HCA 10; 196 CLR 101 was a case about proprietary estoppel, in line with the stream of English authority which the High Court traced back to Dillwyn v Llewelyn and Plimmer v Wellington. Various promises had been made to the respondent by his parents that he would be given an interest in development land belonging to them, in reliance upon which he worked without wages and built a house on part of the land. The parents appealed to the High Court on the basis that, contrary to the dicta in Commonwealth v Verwayen, the relief awarded by the courts below (which was partly in specie and partly a financial proxy for the son’s expectation interest) exceeded the cost or value of his detrimental reliance. The High Court decided, unanimously, that the Verwayen case did not require relief for proprietary estoppel to be founded upon compensation for detriment. While by a majority they restored the order of the first instance judge by reference to reasons about other aspects of the equities of the matter than detriment, the result was that an essentially expectation-based monetary award was upheld.

59. To much the same effect was the decision of the High Court in Sidhu v Van Dyke [2014] HCA 19; 251 CLR 505. The claimant sought the transfer to her of a cottage which had been promised to her by the defendant on the faith of which she had relied to her detriment by (inter alia) not seeking a property transfer from her former husband on divorce. She had obtained an order for payment for the value of her promised interest, being denied a specific order for transfer because of the inequity which that would have caused to the defendant’s former wife, who was a co-owner of the land on which it stood. One of the grounds of appeal to the High Court was that the order should have been limited to the cost or value of her reliant detriment, again based upon the dicta in Commonwealth v Verwayen. The High Court’s response is encapsulated in the following passage from the joint judgment of the majority (French CJ, Kiefel, Bell and Keane JJ) at paras 84-85:

“If the respondent had been induced to make a relatively small, readily quantifiable monetary outlay on the faith of the appellant’s assurances, then it might not be unconscionable for the appellant to resile from his promises to the respondent on condition that he reimburse her for her outlay. But this case is one to which the observations of Nettle JA in Donis v Donis [(2007) 19 VR 577, 588-589, para 34] are apposite:

‘ [H]ere, the detriment suffered is of a kind and extent that involves life-changing

decisions with irreversible consequences of a profoundly personal nature…beyond the measure of money and such that the equity raised by the promisor’s conduct can only be accounted for by substantial fulfilment of the assumption upon which the respondent’s actions were based.’

85. The appellant’s argument, rightly, sought no support from the discussion in cases decided before Giumelli v Giumelli of the need to mould the remedy to reflect the ‘minimum relief necessary to “do justice” between the parties’ [Verwayen 170 CLR 394, 416].

There may be cases where ‘[i]t would be wholly inequitable and unjust to insist upon a disproportionate making good of the relevant assumption’ [Verwayen, at p 413]; but in the circumstances of the present case, as in Giumelli v Giumelli, justice between the parties will not be done by a remedy the value of which falls short of holding the appellant to his promises. While it is true to say that ‘the court, as a court of conscience, goes no further than is necessary to prevent unconscionable conduct’ [Waltons Stores (Interstate) Ltd v Maher (1988) 164 CLR 387, 419], where the unconscionable conduct consists of resiling from a promise or assurance which has induced conduct to the other party’s detriment, the relief which is necessary in this sense is usually that which reflects the value of the promise.”

60. Thus did the seed of a detriment-based aim of the remedy in proprietary estoppel, sown in Verwayen, fall on hard Australian ground and wither away. After a momentary wobble their jurisprudence on the issue appears now to have fallen squarely back within that which originated in England in Dillwyn v Llewelyn, Ramsden v Dyson and, with assistance from New Zealand, in Plimmer v Wellington. But the lively controversy to which its transplantation to England has given rise remains to be resolved.

The applicable principles

61. Drawing together this lengthy review of the authorities and looking at the matter historically, I suggest that what has happened may be summarised in this way. For over a century, starting in the 1860s, the courts of equity developed an equitable estoppel-based remedy, the aim of which was to prevent the unconscionable repudiation of promises or assurances about property (usually land) upon which the promisee had relied to his detriment. The normal and natural remedy was to hold the promisor to his promise, because that was the simplest way to prevent the unconscionability inherent in repudiating it, but it was always discretionary, and liable to be tempered by circumstances which might make strict enforcement of the promise unjust, either between the parties or because of its effect on third parties. While reliant detriment was a necessary condition for the equity to arise, the court’s focus on holding the promisor to his promise was not aimed at “protecting” the promisee from the detriment, still less compensating for it. It was aimed at preventing or remedying the unconscionability of the actual or threatened conduct of the promisor, with the effect, but not the aim, that it tended to satisfy the expectations of the promisee.

62. The experience of having to frame an appropriate remedy to do justice in the infinitely variable exigencies of real life threw up numerous practical problems to answer which the courts devised practical (rather than doctrinaire) solutions. Thus the court could substitute payment of the value of the expectation constituted by the promise rather than enforcement in specie where the promisor had sold the promised property, or where specific enforcement would cause injustice to a third party with an interest in it, or with a dependency upon its continued use. Occasionally the court concluded that the repudiation of the promise would not, in changed circumstances from those in which it was made, be unconscionable at all. More often in such cases the court might require some smaller monetary payment to be made than one which represented the full value of the promised expectation.

63. A particular problem in some of the cases (the “clean break cases”) arose where full enforcement of the promise would leave warring parties in cohabitation with each other. For the same reason that equity does not enforce a contract for personal services this usually required the court to remedy the unconscionability either by a mixed in specie and monetary award, or by a pure monetary award, but even then generally by reference to the value of the promised expectation.

64. A potentially acute problem arose, but not often in the reported cases, where (as here) the repudiation of the promise occurred long before it was due to be performed. This might often accompany the clean break problem, but it created a justice issue between the parties and sometimes family dependents which was conceptually distinct from the need to avoid enforced cohabitation.

65. The inherent flexibility and pragmatism of equitable relief enabled the courts to address all these problems as they arose without having to frame a rule book for the purpose, but while pursuing the invariable aim of preventing or putting right unconscionable conduct. Sometimes the solutions were simple and obvious. Sometimes an experienced court devised a complex solution which had previously eluded the court in earlier cases. But in none of them until the last 25 years did there appear to be a perception that the aim of the whole exercise was to protect from or compensate for detriment, or that there needed always to be a relationship of proportionality between the detriment and the remedy. In some cases a very marked disparity between the length of the period of detrimental reliance and the enduring nature of the promised property right did operate as a ground for something less than strict enforcement of the promise, on the common-sense basis that to ignore it would be to fail to do justice between the parties.

66. Nor did there appear to be a concern that the breadth and flexibility of the equitable remedy made it too much of an approximation to the length of the Chancellor’s foot.

67. A perception on doctrinaire grounds that all might not be well with the underlying principles of proprietary estoppel arose from minority dicta about a different estoppel in Australia in Commonwealth v Verwayen, to the effect that the true aim of the remedy was to prevent or compensate for the detriment. Put in harness with Lord Scarman’s often misunderstood “minimum equity to do justice” dictum in Crabb (which may have been influential in Verwayen itself) it sprouted in England in the form of two new themes. The first, developed judicially, was that the remedy ought not to be disproportionate to the detriment. The second, more radical, suggestion developed by some academic commentators in the present century was that maybe the true aim of the remedy ought now to be recognised as detriment-based, and that this might reduce harmful uncertainty as to likely remedy among litigants and their advisors.

68. I have already noted that the two themes are not easily reconciled. If the true aim of the remedy is to compensate for detriment then it should be done as precisely as possible, using all the common law court’s formidable techniques for monetarising almost everything, and treating the rest as too remote. But if the aim lies as I think elsewhere (to remedy unconscionability mainly by satisfying expectation) then a cross-check by reference to whether a proposed remedy is out of all proportion to the detriment is a useful guard against potential injustice.

69. My reading of the authorities tells me that the notion that the aim of the remedy is detriment-based has not taken root in England. It was expressly rejected in Jennings v Rice, and no more than toyed with in Davies v Davies. In Moore v Moore [2018] EWCA Civ 2669; [2019] 1 FLR 1277 at paras 25-26 Henderson LJ (with whom Leggatt and Floyd LJJ agreed) said that he would be wary of giving primacy to the detriment-based approach in a field where cases are so fact-sensitive and proportionality has such a prominent role to play.

70. Meanwhile it has been comprehensively rejected as the aim of a proprietary estoppel remedy in Australia. I have already explained why I regard it as wrong both in principle and in its likely effect. If the detriment consists of something done for or given to the promisor the remedy has the superficial appearance of being a kind of restitution, but that is not the same as equity. Otherwise it seems supportable only on the highly artificial tortious basis that the original promise or assurance, however well meant, is by its later repudiation somehow turned retrospectively into a wrong, causing the harm constituted by the detriment. I have explained why, with respect, I regard that as a reversal of the reality. The wrong is the repudiation and the harm is the non-fulfilment of the promise thereafter. The reliant conduct has occurred in full before the wrong is even committed. To treat it as harm caused by the wrong is incoherent. Some maintain that the reliant conduct is somehow converted into harm by the repudiation of the promise. But that is only because the promisee is being deprived of the expected benefit of the promise.

71. In my view therefore this court should firmly reject the theory that the aim of the remedy for proprietary estoppel is detriment-based forms any part of the law of England. I acknowledge that the common law (and perhaps even equity) could have based itself on such a theory, and I accept that the concept that the remedy compensates for detriment is one which will appeal to some minds. But the cases show that equity did not take that course, and there is no good reason for doing so now, by a reversal of over 150 years’ careful development of the remedy upon a different foundation.

72. By contrast the concept of a proportionality test does appear to have taken root in England, as part of the assessment of whether a proposed remedy to deal with the proven unconscionability based on satisfying the claimant’s expectation works substantial justice between the parties. It has become a well-used part of the relevant equitable toolkit in the Chancery Division: see e.g. my own decision in Hopper v Hopper [2008] EWHC 228 Ch; [2008] 1 FCR 557, paras 102-104, where its use was a matter of agreement between counsel. Like most tools or rules for the examination whether something produces justice, it is a good servant but a bad master. It is no more nor less than a useful cross-check for potential injustice. As Robert Walker warned in Jennings v Rice, it is not to be applied by reference to any detailed mathematical examination of wage rates or interest rates. The question is, as he put it, whether the proposed remedy is “out of all proportion to the detriment”. The true “value” of the detriment may be impossible to assess with anything approaching confidence. The counterfactual of an education and working life of a very different kind may be too speculative to quantify. But that does not mean that the non-financial element of the detriment should be ignored, as if it were too remote. Prima facie, wherever the reliant detriment has (as here) had lifelong consequences, a detriment valuation analysis will fall upon stony ground. As noted in the relevant cases, it is where the detriment is specific and short-lived, and in particular shorter than the parties are likely to have contemplated, that it is likely to serve a useful purpose. And that purpose is not generally to serve as even an approximate yardstick for a monetary award. In my view the best summary of the proportionality test is that the remedy should not, without some good reason, be out of all proportion to the detriment, if that can readily be identified. If it cannot, then the proportionality test is unlikely to be of much use.

73. Finally, the question of proportionality is not to be carried out on the basis of a purely financial comparison. Take the example where the daughter spends the whole of her working life on the family farm, working at low wages, in the promised expectation that she will inherit it. The question whether giving her the farm is disproportionate is not to be answered in such a case simply by comparing the monetary value of the farm with the net present value of the wages differential. Modern capital values of farmland are typically so high that the farm would always be worth much more than any valuation of the detriment. But that does not make a full in specie enforcement of the expected inheritance disproportionate. It will be proportionate (or at least not out of all proportion) because the daughter has fulfilled her part of the family understanding, and it is only fair and proportionate that the parents should now perform theirs.

74. I consider that, in principle, the court’s normal approach should be as follows. The first stage (which is not in issue in this case) is to determine whether the promisor’s repudiation of his promise is, in the light of the promisee’s detrimental reliance upon it, unconscionable at all. It usually will be, but there may be circumstances (such as the promisor falling on hard times and needing to sell the property to pay his creditors, or to pay for expensive medical treatment or social care for himself or his wife) when it may not be. Or the promisor may have announced or carried out only a partial repudiation of the promise, which may or may not have been unconscionable, depending on the circumstances.

75. The second (remedy) stage will normally start with the assumption (not presumption) that the simplest way to remedy the unconscionability constituted by the repudiation is to hold the promisor to the promise. The promisee cannot (and probably would not) complain, for example, that his detrimental reliance had cost him more than the value of the promise, were it to be fully performed. But the court may have to listen to many other reasons from the promisor (or his executors) why something less than full performance will negate the unconscionability and therefore satisfy the equity. They may be based on one or more of the real-life problems already outlined. The court may be invited by the promisor to consider one or more proxies for performance of the promise, such as the transfer of less property than promised or the provision of a monetary equivalent in place of it, or a combination of the two.

76. If the promisor asserts and proves, the burden being on him for this purpose, that specific enforcement of the full promise, or monetary equivalent, would be out of all proportion to the cost of the detriment to the promisee, then the court may be constrained to limit the extent of the remedy. This does not mean that the court will be seeking precisely to compensate for the detriment as its primary task, but simply to put right a disproportionality which is so large as to stand in the way of a full specific enforcement doing justice between the parties. It will be a very rare case where the detriment is equivalent in value to the expectation, and there is nothing in principle unjust in a full enforcement of the promise being worth more than the cost of the detriment, any more than there is in giving specific performance of a contract for the sale of land merely because it is worth more than the price paid for it. An example of a remedy out of all proportion to the detriment would be the full enforcement of a promise by an elderly lady to leave her carer a particular piece of jewellery if she stayed on at very low wages, which turned out on valuation by her executors to be a Faberge worth millions. Another would be a promise to leave a generous inheritance if the promisee cared for the promisor for the rest of her life, but where she unexpectedly died two months later.

77. There is in my view real merit in Lord Walker’s spectrum (as he would now prefer to call it) between on the one hand a case where both the promise and the detriment are reasonably precisely defined by the time when the promise is repudiated, where the one is in a sense the quid pro quo of the other although falling short of contract, and on the other hand where either or both are left much less certain. The “almost contractual” end of the spectrum is likely to generate the strongest equitable reason for the full specific enforcement of the promise if the reliant detriment has been undertaken in full, regardless of a disparity in value between the two. At the other end there may be much greater scope for a departure from full enforcement, even if there are no other problems making it just to do so.

78. Cases where at the time of a repudiation during the lifetime of the promisor the date of performance lies in the future, e.g. upon the death of the promisor, are likely to be the most difficult in terms of finding an appropriate remedy. They may provoke objections to a strict enforcement by both sides. The promisor will complain that he never promised to part with the property, or its value, in his lifetime, and that to do so earlier would cause him and his dependents unjust hardship. If the promisor proposes that the promisee be given a reversionary interest in the promised property, then (as in the present case) the promisee may say that the repudiation has so fouled the parties’ relations that only a clean break will do. This may be a fair claim where the promise to transfer property at a future date carried with it (as here) the implication that the promisee would be able to live and work there until then. A clean break does not necessarily require an acceleration of the promised benefit, or at least not of the whole of it. But if it does, with an early proxy for performance, it is likely to require an appropriate discount for accelerated receipt.

79.  I can see no principled justification for treating a perceived need to abandon full enforcement as a reason for moving straight (or at all) to compensation on the basis of an attempt to value the detriment. That would suggest something approaching a binary choice which would be alien to the flexible and pragmatic nature of the discretion. I recognise that, in a case where there is perceived to be a large gap between the respective values of the promise and of the detriment this may leave the judge with a wide range of options with little in the way of rules as a guide. In some cases the nature of the problem in the way of full enforcement may point the way to the solution, as in Griffiths v Williams. In an early receipt case the solution, as already noted, may be a discount for acceleration of the expectation. The remedy may have to accommodate the risk that the promisor (of an inheritance) may need to realise part of the promised property to pay for expensive nursing care. There would not normally be anything unconscionable about that. In a case where there is a need to avoid enforced cohabitation the solution may be a financial proxy for the promise rather than enforcement in specie. But where the only objection to full enforcement is that it will be out of all proportion to the detriment then the court will, in the words of Dillon LJ in Burrows v Sharp, just have to do the best it can.

80. In the end the court will have to consider its provisional remedy in the round, against all the relevant circumstances, and ask itself 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. “Minimum equity to do justice” means, in that context, a remedy which will be sufficient to enable that unconscionability question to be answered in the negative.

81. In Vauxhall Motors Ltd (formerly General Motors UK Ltd) v Manchester Ship Canal Co Ltd [2019] UKSC 46, at para 2, I said, about the equitable remedy of relief from forfeiture:

“Relief from forfeiture is one of those equitable remedies which plays a valuable role in preventing the unconscionable abuse of strict legal rights for purposes other than those for which they were conferred. But it needs to be constrained with principled boundaries, so that the admirable certainty of English law in the fields of business and property is not undermined by an uncontrolled intervention of equity in any situation regarded by a judge as unconscionable.”

I adhere to that view, and it is as applicable to proprietary estoppel as to any other equitable remedy, even though the typical context may be family property rather than business and commerce. In the present case the criticism has not been that there are no sufficient principles to govern the circumstances when a judge may intervene. Rather the complaint is that there is insufficient principle to guide the judge as to an appropriate remedy, once the equity has arisen, so that practitioners find it hard to advise their clients as to likely outcome, with the result that cases go to court at great expense and family bitterness whereas otherwise they would settle.

82. I am not persuaded by this. The repudiation of promises of this kind made between family members is likely to be causative of, or at least accompanied by, such bitterness that settlement is always going to be difficult. Since the relevant promises are likely to have been made orally, or even by conduct, the propensity for fundamental disputes of primary fact are themselves likely to be the greatest enemy of any predictability of outcome. Nor is unpredictability as to remedy necessarily a bar to settlement, because the increased risks of a trial for both sides can be a spur to settlement before the litigation becomes a battle purely about costs. But even if it is, that is no reason for the court to invent artificial rules about remedy where there is in truth no underlying supportive principle beyond those which I have described.