Open Access Articles- Top Results for Estoppel


In law, estoppel is a set of doctrines in which a court prevents a litigant from taking an action the litigant normally would have the right to take, in order to prevent an inequitable result. Estoppel occurs when a party "reasonably relies on the promise of another party, and because of the reliance is injured or damaged".[1] For example, estoppel precludes "a person from denying, or asserting anything to the contrary of, that which has, in contemplation of law, been established as the truth, either by the acts of judicial or legislative officers, or by his own deed, acts, or representations, either express or implied".[2]

Etymology and usage

The verb is "estop", which comes from Late Latin stuppare ("to stop up") through Middle English estoppen.[3] The noun form "estoppel" is based on the Old French estoupail, which meant a stopper plug.

Where a court finds that a party has done something warranting a form of estoppel, that party is said to be estopped from making certain related arguments or claiming certain related rights. The defendant is estopped from presenting the related defence, or the plaintiff is estopped from making the related argument against the defendant. Lord Coke stated, "It is called an estoppel or conclusion, because a man's own act or acceptance stoppeth or closeth up his mouth to allege or plead the truth."[4]


Estoppel is essentially a rule of evidence[5] whereby a person is barred from denying a fact that has already been settled.


Promissory estoppel is often applied where there is an agreement without a consideration, or the consideration is future based (as a promise). When applied in defense by a defendant it may be called a "shield", and where applied by a plaintiff it may be called a "sword".[7][8] It is most commonly used as a shield,[9] with some commentators stating that it can only be used as a shield, although this varies with jurisdictions.[10]


Estoppel can be understood by considering examples such as the following:

  1. A city entered into a contract with another party. The contract stated that it had been reviewed by the city's counsel and that the contract was proper. Estoppel applied to estop the city from claiming the contract was invalid.[11]

Major types



Reliance-based estoppels

Reliance-based estoppels (at English law) include:[12]




  • what the victim did must either have been reasonable, or
  • the victim did what the representor intended, and


  • there was a promise
  • that was reasonably relied upon
  • resulting legal detriment to the promisee
  • justice requires enforcement of the promise



  • the content of the promise/representation;
  • the relative knowledge of the parties;
  • the nature and context of the parties' relationship;
  • the parties' relative strength of position;
  • the history of the parties' relationship; and

But in Cobbe v Yeoman's Row,[14] Lord Scott of Foscote stated the following:


Estoppel by representation of fact (Law of England and Wales)


Spencer Bower defines estoppel by representation of fact as follows:[15]


A second definition comes from Sean Wilken and Theresa Villiers:[16]:para. 9.02



Equitable estoppel (American law)

Equitable estoppel is the American counterpart to estoppel by representation. Its elements are summarized as:[17]

  • Facts misrepresented or concealed
  • Knowledge of true facts
  • Fraudulent intent
  • Inducement and reliance
  • Injury to complainant
  • Clear, concise, unequivocal proof of actus (not by implication)

For example, in Aspex Eyewear v. Clariti Eyewear, eyeglass frame maker Aspex sued competitor Clariti for patent infringement.[18] Aspex waited three years, without responding to a request that it list the infringed patent claims, before asserting its patent in litigation. During this period, Clariti expanded its marketing and sales of the products. The Federal Circuit found that Aspex misled Clariti to believe it would not enforce its patent, and thus estopped Aspex from proceeding with the suit.[19]

Promissory estoppel

In many jurisdictions of the United States, promissory estoppel is an alternative to consideration as a basis for enforcing a promise. It is also sometimes called detrimental reliance.


—Restatement (Second) removed the requirement that the detriment be "substantial".


—28 Am Jur 2d Estoppel and Waiver § 34

Suppose that B goes to a store and sees a sign that the price of a radio is $10. B tells the shopkeeper that he will get the money and come back later that day to purchase it; there is no discussion of price. The shopkeeper says that when B returns, he will welcome B as a customer — unless he sells all three of his radios first. Hearing this, B goes and sells his watch for $10 (it was really worth $15, but since B wanted the money right away, he chose not to wait for the best price). When B returns, the sign says $11, and the owner tells B that he has raised the price. In equity, can you argue that the shopkeeper is estopped by conduct? B relied upon the implied representation that a radio would be sold for $10 when he returned with the money; B has sold his watch at a discount, to his detriment. (This element would be absent if B sold the watch at the market price.) But the shopkeeper did not guarantee to hold one of the radios against the possibility of B's return nor did they agree a fixed price.


The drafters of the Second Restatement debated how to calculate the amount of damages flowing from a promissory estoppel, using the following example: A young man's uncle promises to give him $1,000 to buy a car. The young man buys a car for $500, but the uncle refuses to pay any money. Is the young man entitled to $1,000 (the amount promised), or merely $500 (the amount he actually lost)? The Restatement states that "The remedy granted for breach may be limited as justice requires." — leaving quantification to the discretion of the court.

Equitable estoppel (English law)

Under English and Australian legal systems, estoppels in equity include promissory and proprietary estoppels, described below. (Contrast with estoppel by representation, which is a claim (under the English system) at law.)

Proprietary estoppel

Main article: Proprietary estoppel

In English law, proprietary estoppel is distinct from promissory estoppel. Proprietary estoppel is not a concept in American law, but a similar result is often reached under the general doctrine of promissory estoppel.

Traditionally, proprietary estoppel arose in relation to rights to use the land of the owner, and possibly in connection with disputed transfers of ownership. Although proprietary estoppel was only traditionally available in disputes affecting title to real property, it has now gained limited acceptance in other areas of law. Proprietary estoppel is closely related to the doctrine of constructive trust.[14]

J. Fry summarized the five elements for proprietary estoppel as:[20]

  • the claimant
    • made a mistake as to his legal rights (typically because the actual owner attempted to convey the property, but the transfer is invalid or ineffective for some reason);
    • did some act of reliance;
  • the defendant
    • knows of the existence of a legal right which he (the defendant) possesses, and which is inconsistent with the right claimed by the claimant;
    • knows of the claimant's mistaken belief; and
    • encouraged the claimant in his act of reliance.

Example: A father promised a house to his son who took possession and spent a large sum of money improving the property, but the father never actually transferred the house to the son. Upon the father's death, the son claimed to be the equitable owner. The court found the testamentary trustees (as representatives of the deceased father's estate) were estopped from denying the son's proprietary interest, and ordered them to convey the land to the son.[21]

Promissory estoppel


A promise made without consideration is generally not enforceable. It is known as a bare or gratuitous promise. Thus, if a car salesman promises a potential buyer not to sell a certain specific car over the weekend, but does so, the promise cannot be enforced. But should the car salesman accept even one penny in consideration for the promise, the promise will be binding and enforceable in court by the potential buyer. Estoppel extends the court's purview even to cases where there is no consideration, though it is generally not a 'sword': not a basis on which to initiate a lawsuit.

The doctrine of promissory estoppel was first developed in Hughes v. Metropolitan Railway Co [1877] but was lost for some time until it was resurrected by Denning J in the controversial case of Central London Property Trust Ltd v High Trees House Ltd.[22]

Promissory estoppel requires:

  1. an unequivocal promise by words or conduct

In general, estoppel is "a shield not a sword"—it cannot be used as the basis of an action on its own.[23] It also does not extinguish rights. In High Trees the plaintiff company was able to restore payment of full rent from early 1945, and could have restored the full rent at any time after the initial promise was made provided a suitable period of notice had been given. In this case, the estoppel was applied to a "negative promise", that is, one where a party promises not to enforce full rights.


The general rule is that when one party agrees to accept a lesser sum in full payment of a debt, the debtor has given no consideration, and so the creditor is still entitled to claim the debt in its entirety. This is not the case if the debtor offers payment at an earlier date than was previously agreed, because the benefit to the creditor of receiving payment early can be thought of as consideration for the promise to waive the rest of the debt. This is the rule formulated in Pinnel's Case,[24] and affirmed in Foakes v Beer.[25]

The decision of the Court of Appeal in Collier v P & MJ Wright (Holdings) Ltd suggests that the doctrine of promissory estoppel can now operate to mitigate the harshness of this common law rule.[26] Moreover, Arden LJ held that allowing a creditor to renege on his promise to forebear seeking the balance of a debt in return for part payment would be, in and of itself, inequitable. Therefore, the only reliance that the promisee must demonstrate is the actual making of the part payment. This approach has been criticised as doing violence to the principle set down in Hughes and the extent to which the other members of the Court, namely Longmore LJ, agreed with it is uncertain.

Other estoppels




Estoppel by convention in English law (also known as estoppel by agreement) occurs where two parties negotiate or operate a contract but make a mistake. If they share an assumption, belief, or understanding of the contract's interpretation or legal effect, then they are bound by it, if:[citation needed]

  1. They both knew the other had the same belief, and
  2. They both based their subsequent dealings on those beliefs.

Estoppel by convention is most commonly invoked if one party wishes to rely on pre-contract negotiation as an aid to construction of the contract.[27]

It is debatable whether estoppel by convention is a separate estoppel doctrine, or merely a case of reliance-based estoppel (estoppel by representation would be its most frequent form), or of the rule of interpretation that, where words in a contract are ambiguous, one always interprets those words so as to give effect to the actual intentions of the parties even if that would not be the usual legal outcome (see Amalgamated Investment and Property Co. Ltd. v Texas Commerce International Bank Ltd [1982] QB 84).





Main article: Estoppel by deed


Conflict estoppel

"[An] inconsistent position, attitude or course of conduct may not be adopted to loss or injury of another".[28] For example, as between two or more claimants, a party that takes multiple and inconsistent legal positions is estopped to assert its positions against another consistent and certain claim, i.e. preferential treatment for certain over uncertain claims.

Issue estoppel

See also: Res judicata

Issue estoppel (more commonly known as issue preclusion) prevents, in some cases, an issue that has already been litigated and decided on the merits from being re-litigated, even when the parties are different. In the world of crime, some cases have achieved notoriety, e.g. in the Birmingham Six saga, the House of Lords ruled in Hunter v Chief Constable of the West Midlands Police (1982) that issue estoppel applied. Lord Diplock said:


In other countries


The doctrine of promissory estoppel was adopted into Australian law in Legione v. Hateley.[30] However, the plaintiffs were unsuccessful in that case because the reliance was unreasonable and the promise not unequivocal.

Australian law has now gone beyond the position espoused in the English High Trees case[31] to cases where there is no pre-existing legal relationship between the two parties, and promissory estoppel can be wielded as a "sword", not just as a "shield". Mason CJ and Wilson J in Waltons Stores (Interstate) Ltd v Maher[32] held that if estoppel is proven, it gives rise to an equity in favour of the plaintiff, and the court will do the minimum equity that is just in the circumstances. From this case, it is also possible for the promise to come from silence or inaction.

Stated by Brennan J in Waltons Stores:
To establish an equitable estoppel, it is necessary for the plaintiff to prove that 1) the plaintiff assumed that a particular legal relationship would exist between them (and in the latter case) that the defendant would not be free to withdraw from that expected legal relationship; 2) the defendant has induced the plaintiff to adopt that assumption or expectation; 3) the plaintiff acts or abstains from acting in reliance on the assumption or expectation; 4) the defendant knew or intended him to do so; 5) the plaintiff's action or inaction will occasion detriment if the assumption of expectation is not fulfilled; and 6) the defendant has failed to act to avoid that detriment whether by fulfilling the assumption or expectation of otherwise.

Although there is some debate as to whether "unconscionability" is an element that English courts need to take into account when considering estoppel by representation of fact, the Australian courts clearly do.[16]:para. 9-03[33] This element is satisfied if one party encourages the other party to create assumptions that lead to reliance. [34]

Today, the principle of estoppel may give birth to an enforceable obligation even without a consideration under the following conditions:

  1. promise
  2. dishonest behaviour of the promisor
  3. special relationship between the promisor and the promisee (e.g., duty of information)
  4. irreversible change of position on the part of the promisee

When enforcing an estoppel, Australian courts will look to the impact that enforcement will have on others, especially third parties. Relief in estoppel thus remains discretionary, and will not always be granted based on the expectation of the plaintiff.[35]

The status of estoppel by representation of fact is less clear in Australia. Two seminal decisions purport to fuse common law and equitable estoppels into a single unified doctrine,[36] but the New South Wales Court of Appeal[37] continues to treat estoppel by representation at common law as distinct from equitable estoppel.[38] This can be significant in deciding which court has jurisdiction to adjudicate on the issue.



So, for instance, if A intentionally and falsely leads B to believe that certain land belongs to A, and thereby induces B to buy and pay for it, and only later does A acquire the land, then A is not allowed to argue to void the sale on the ground that, at the time of the sale, he had no title.[39]

The doctrine of estoppel is based on the principle that consistency in word and action imparts certainty and honesty to human affairs. If a person makes a representation to another, on the faith of which the latter acts, to his prejudice, the former cannot recant the representation.

However, estoppel has no application to representations made regarding the fundamental rights conferred by the Constitution of India, the source of all laws, which exists not only to benefit individuals but to secure collective rights. Thus, no one can barter away the freedoms conferred upon him by the Constitution. A concession made by him in a proceeding, whether under a mistake of law or otherwise, that he does not possess or will not enforce any particular fundamental right, cannot estop him, as enforcing estoppel would defeat the purpose of the Constitution.[6]

See also


  1. ^ "Estoppel legal definition". legaldictionary, Retrieved August 20, 2014. 
  2. ^ "Lawlink", 28 Am Jur 2d Estoppel and Waiver § 1
  3. ^ American Heritage Dictionary of the English Language
  4. ^ 2 Coke, Littleton 352a
  5. ^
  6. ^ a b India -- Olga Tellis v. Bombay Municipal Corporation (1985.07.10) (Right to Life and Livelihood for Homeless)
  7. ^ Promissory Estoppel Serves as a Shield and a Swords Guarding Unconscionable | Ester Lioe -
  8. ^ Australian Contract Law | Julie Clarke
  9. ^ Promissory Estoppel is a shield not a sword - University Law - Marked by
  10. ^ Contract Law lecture - Estoppel - its origins and forms
  11. ^ Speckman v. City of Indianapolis, 540 N.E.2d 1189, 1191 (Ind. 1989).
  12. ^ Halsbury's Laws of England, Vol 16(2), 2003
  13. ^ Spence, Michael (1999). Protecting Reliance: The Emergent Doctrine of Equitable Estoppel. Hart Publishing. pp. 60–66. ISBN 9781901362626. 
  14. ^ a b Cobbe v Yeoman's Row [2008] UKHL 55
  15. ^ Bower, Spencer (2004). The Law relating to Estoppel by Representation (4th ed.). para. I.2.2. 
  16. ^ a b Wilken, Sean; Villiers, Theresa (2002). The Law of Waiver, Variation and Estoppel (2nd ed.). Oxford University Press. 
  17. ^ Cox, Lucian B. (1951). Equity: Principles and procedures in Virginia and West Virginia. § 288. 
  18. ^ Aspex Eyewear v. Clariti Eyewear Court Decision
  19. ^ Joel Leeman, "Silence is Deadly: The Peril of Inaction After Calling Someone an Infringer", Sunstein IP Update (June 2010)
  20. ^ Wilmott v Barber (1880) 15 Ch D 96
  22. ^ Central London Property Trust Ltd v High Trees House Ltd [1947] K.B. 130
  23. ^ Combe v Combe (1951) 2 KB 215
  24. ^ Pinnel's Case (1602) 5 Co Rep 117a
  25. ^ Foakes v Beer (1884) 9 App Cas 605
  26. ^ Collier v P & MJ Wright (Holdings) Ltd 2008 1 WLR 643
  27. ^ Chartbrook Ltd and another v Persimmon Homes Ltd and another [2009] UKHL 38
  28. ^ Brand v. Farmer’s Mut. Protective Assoc of Texas, Tex. App 95 S.W.2d 994, 997
  29. ^ Judgments - Polanski (Appellant) v Conde Nast Publications Limited (Respondents) UK Parliament publications > Business > Lords Publications > Judgment Index > Judgment. Paragraph 86
  30. ^ Legione v. Hateley (1983) 152 CLR 406
  32. ^ Waltons Stores (Interstate) Ltd v Maher (1988) 164 CLR 387
  33. ^ The Commonwealth v Verwayen (1990) 170 CLR 394 at 444 per Deane J.
  34. ^ Thompson v Palmer [1933] HCA 61
  35. ^ Giumelli v Giumelli (1999) 196 CLR 101; see also Delaforce v Simpson-Cook [2010] NSWCA 84 (20 July 2010) AUSTLII
  36. ^ Waltons Stores (Interstate) v Maher (1988) 164 CLR 387 and Commonwealth v Verwayen (1990) 170 CLR 394
  37. ^ Byron Shire Council v Vaughan [2002] NSWCA 158
  38. ^ Meagher, Gummow & Lehane, Equity: Doctrines & Remedies, 4th edition, Butterworth: 2002, Chapter 17; and Pakinson, The Principles of Equity, 2nd edition, LBC: 2003, Chapter 7.
  39. ^ Section 115 in The Indian Evidence Act, 1872


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