Promissory Estoppel: Doctrine, Case Law, and Legal Implications

This essay provides a comprehensive analysis of the doctrine of promissory estoppel, a significant concept in contract law. It begins by defining promissory estoppel and its origins in equity, emphasizing its role in mitigating the strict application of legal rights. The essay explores key case law, including Crabb v Arun DC, Central London Property Trust Ltd. v High Trees House Ltd., and Combe v. Combe, to illustrate the principles and limitations of the doctrine. It examines the requirements for establishing promissory estoppel, such as a clear promise, reliance by the promisee, and inequity if the promisor goes back on the promise. A crucial aspect of the discussion is the principle that promissory estoppel acts as a shield, not a sword, meaning it can only be used as a defense and not to create a new cause of action. The essay further discusses the relationship between promissory estoppel and consideration, highlighting that the doctrine does not replace the need for consideration in forming a contract. It concludes by reinforcing the significance of promissory estoppel as a tool to prevent unfairness and uphold promises in legal relationships, as supported by the case law examined.

Question 1
The doctrine of promissory estoppel prevents (estops) a claimant from going back on a
promise and has been described as a ‘shield and not a sword’.
Undertake an evaluation of this statement using related case law.
Promissory estoppel can be described as one of the popular types of equitable estoppel. The
significance of equitable estoppel has been stressed upon by the court in Crabb v Arun DC
(1976). While emphasizing on the importance of equitable estoppel, the court stated that equity
comes in to mitigate the rigors of the application of strict law. It also prevents the person from
insisting on the strict application of his or her legal rights when under the circumstances, it will
be in equitable for such person to do so, keeping in view the dealings that have taken place
among the parties. The doctrine of promissory estoppel can be explained with the help of the
following example. Therefore, when A has made a promise to B according to which A is not
going to enforce his legal right and B has relied and acted upon such promise without supplying
any consideration, equity will not allow A to back up from such a promise later on (Hughes v
Metropolitan Rly Co (1877).
A significant case related with promissory estoppel is that of Central London Property Trust Ltd.
v High Trees House Ltd. (1974). In the same way, the court has also explained the doctrine of
promissory estoppel in Total Metal Manufacturing Ltd V. Tungsten Electric Co Ltd. (1955). The
principle of promissory estoppel is different from estoppel under the common law due to the
reason that in this case, there are less strict requirements present. Therefore promised the

estoppel may arise on the basis of the promise regarding future intention or conduct. The
application of the doctrine of promissory estoppel can also be seen in the case of Hughes V.
Metropolitan Railway (1877). In this case, the tenant was given the time of six months by the
landlord to repair the property, otherwise there was risk of forfeiture. During the six months,
negotiations started between the landlord and the payment for the sale of the lease. However
after six months, the negotiations between the parties failed at at the same time the team and also
failed to repair the property. Under these circumstances, the landlord initiated action to enforce
forfeiture. However, the decision given by the court was that on account of the conduct of the
landlord, the tenant was led to believe that the forfeiture was not going to be enforced by the
landlord.
The brief facts of Central London Property Trust Ltd v High Trees House Ltd. (1947) are that a
block of flats was led by the plaintiff to the defendant on a lease for 99 years at the rate of £2 500
per year. As a result of the evacuation of people from London during the World War, the
defendant could not sublet enough lives so that the rent could be covered. Under these
circumstances, the plaintiff agreed that only half of the rent will be charged. However, at the end
of the war, the property market stabilized. As a result, the defendant, succeeded in subletting all
the flats. Under these circumstances, the plaintiff asked that original rent should be paid by the
defendant, however the defendant refused to pay the original rent.
Under these circumstances, the issue in this case was if the promise made by the landlord can be
enforced even if there was no consideration present to support the promise.
In this case the court stated that the statement made by the landlord was the representation
regarding the future. It was a promise to suspend the right of the plaintiff to claim for rent during
the war. The plaintiff was aware that the promise would be acted upon and the defendant had

indeed acted on the promise (D & C Builders v Rees, 1965). It was enforceable, even if there
was no consideration but only during the time when the conditions leading to the promise were
present (lack of demand for accommodation during the war). As these conditions seized to exist
in 1945, the court stated that from this point, the plaintiff was allowed to claim the original rent.
The decision given in this case reveals some of the major elements of promissory estoppel.
Therefore it can be stated that the doctrine of promissory estoppel requires that there should be a
promise to waive strict legal rights, such promise, should be made intention of creating legal
relations and it should be intended to be acted upon by the other party. It is also necessitate that
there should be an act done by relying on the promise, although it is not necessary that there
should be detrimental reliance on the promise.
Another important element that needs to be noted in this regard that promissory estoppel only
operates as a shield and it cannot act as a sword. Hence, the promise was not result in creating a
cause of action, but the courts will prevent the party making the promise from acting
inconsistently with the promise. In this case, it was stated by Denning J that it can be said that in
any case, estoppel would cease to operate when the condition due to which the representation
applied had come to an end or it can also be stated that it would only come to end on notice.
However in either case, it is merely a way of ascertaining the scope of the representation.
Therefore, Denning J. has discussed the position that if an attempt would have been made by the
plaintiff to claim the full rent for the wartime period, according to him the claim would have
failed.
Promissory estoppel takes place when a contractual relationship is present between the parties.
However, it is not yet settled if promissory estoppel can also be present in case of pre-contractual
relationships. But in this regard, in Brinkom Investments Ltd V. Carr (1979), Lord Denning had

stated that promissory estoppel can be the result of a promise that has been made by the parties
while they are negotiating the contract. Similar views had been expressed by the court in Durham
Fancy Goods V. Michael Jackson (1969). In this case, Donaldson J, had stated that contractual
relationship is not relevant. If there is a "pre-existing legal relationship, that may result in giving
rise to penalties and liabilities under certain circumstances.
In case of promissory estoppel, the first requirement is that the promisor should give an
unambiguous and clear statement that it was not his intention of enforcing his legal rights. Such a
promise can be either express or implied. In the same breed is also required that the promisee
should have acted on. the promise that was made by the promisor. Generally, promissory
estoppel arises when the promisee had relied on such a promise and suffered a detriment. As was
the case in Ajayi V. Briscoe (1964), or even the promisee had altered its position by relying on
such promise even if he had not suffered any detriment.
In this way, Lord Denning had stated in Alan Co. Ltd V El Nasr & Import Co. (1972) that
suffering a detriment, cannot be described as an essential element necessary in case of
promissory estoppel. Therefore, in order to have a successful plea of promissory estoppel there
should be a change in the circumstances of the promisee.
Another requirement present in case of promissory estoppel is that it would be inequitable if the
promisor is allowed to go back from its promise and claim the strict legal rights after the other
party had relied on such promise. Promising estoppel also requires that it cannot be enforced
against the promisor. As a result, promissory estoppel can only be used as a defense and hence it
cannot be used as a sword. The leading case in this regard is that of Combe V. Combe (1951). In
this case, the court had stated that promissory estoppel does not result in creating a cause of
action. Consequently, the requirement of consideration for the purpose of the formation of

contract is still valid. The court stated that the doctrine of promissory estoppel is a rule of
evidence. It prevents the promisor from denying the truth of the statement on which the other
party had relied upon.
In this case, a promise was made by the defendant has been according to which he was going to
give £100 tax-free to his wife even if no consideration was furnished by the wife in return of the
promise. When the husband failed to get the money, the wife sued the husband regarding the
promise. However, the claim of the wife failed. The court stated that the principle given in High
Trees does not extend to cover such cases. The court stated that promissory estoppel is only a
defense and it cannot be treated as a cause of action. In this way the court stated that it is a shield
and not the sword. This phrase was adopted by Birkett LJ from the counsel of the husband when
he said that the principle of promissory estoppel is to be used as a shield and not as a sword.
In this way, it needs to be noted that the principle of promissory estoppel does not result in
creating a new cause of action. Promising estoppel only prevents a party from asserting its strict
legal rights, under the circumstances when it will be unjust to allow such party to enforce the
right, keeping in view the dealings that have taken place between the parties.
After considering the case law on the issue of the need for consideration, it can be stated that in
none of the cases, the defendant had sued on the basis of the promise, assertion or assurance as a
cause of action in itself. The defendant had been sued on some other cause of action, for
example, a breach of contract or possession. In such a case, the promise or the assertion had only
played a supplementary role, although there is no doubt that it was also significant. Therefore,
even if it is a part of the cause of action, still it cannot be treated as the cause of action in itself.
Thus the principle can be described as follows. Where, through its words or conduct, one party
has made a promise on an assurance to the other party, which was going to affect the legal

relations present between the parties and to be acted accordingly, in such a case, if the other
party had accepted it and acted upon it, the party giving the assurance cannot be allowed later on
to revert back from the earlier legal relations by assuming that no such promise or assurance has
been given, but such party is required to accept the legal relations subject to the qualification that
had been introduced by the party itself although it was not supported by any consideration, but
only by the word of such party.
In view of the above mentioned the discussion, it can be stated that the doctrine of promissory
estoppel has to be only used as a defense and not as a cause of action. Therefore, generally,
promissory estoppel is available as a shield, and not as a sword. The defense of promissory
estoppel is available only against the promisor for enforcing the promise. For the purpose of
using the doctrine of promissory estoppel as a sword, it is necessary to follow the doctrine of
consideration.

References
Ajayi V. Briscoe (1964) 1 WLR 1326
Alan Co. Ltd V El Nasr & Import Co. (1972) 2 QB 18
Brinkom Investments Ltd V. Carr (1979) CA
Central London Property Trust Ltd. v High Trees House Ltd. (1974) 1 KB 130
Combe V. Combe (1951) CA
Crabb v Arun DC (1976) 1 CH 179
D & C Builders v Rees (1965) 2 QB 617
Durham Fancy Goods V. Michael Jackson (1969) 2 QB 839
Hughes v Metropolitan Rly Co (1877) 2 App Cas 439
Total Metal Manufacturing Ltd V. Tungsten Electric Co Ltd. (1955) 1 WLR 761