What Is Acceptance?
Acceptance is defined as a final and unqualified assent to the terms of an offer. This definition, attributed to Professor Treitel, captures two essential requirements: the acceptance must be unconditional, and it must correspond precisely to the terms proposed by the offeror. Any response that purports to accept but introduces new or modified terms will not constitute acceptance in law.
Final and Unqualified Assent
For acceptance to be valid, it must mirror the offer exactly. If an offeree attempts to accept on different terms, that response operates as a counter-offer rather than an acceptance. Critically, a counter-offer destroys the original offer, which cannot thereafter be revived and accepted. This principle was firmly established in Hyde v Wrench [1840], where the defendant offered to sell his farm for £1,000. The claimant counter-offered £950, which the defendant rejected. When the claimant then purported to accept the original offer of £1,000, the court held that no contract had been formed: the counter-offer had extinguished the original offer entirely.
It is important to distinguish a counter-offer from a mere request for information. In Stevenson v McLean [1880], the claimant's enquiry as to whether the defendant would accept payment by instalments was treated as a request for information rather than a counter-offer, leaving the original offer intact and open for acceptance.
Battle of the Forms
In commercial dealings, parties often exchange their own standard-form documents during negotiations — for example, a buyer sends a purchase order on its standard terms, and the seller responds with an acknowledgement on its own standard terms. This situation, commonly described as a "battle of the forms", creates difficulty in identifying which set of terms governs the contract.
The Last Shot Doctrine
English courts have generally adopted what is known as the "last shot" approach. In Butler Machine Tool Co Ltd v Ex-Cell-O Corporation (England) Ltd [1979], the Court of Appeal held that the set of terms or documents exchanged or agreed last will prevail as a counter-offer to all prior terms. Each exchange of standard forms operates as a counter-offer replacing what came before, and the party who fires the "last shot" — whose terms are the final set in the sequence — will have its terms govern the contract.
Acceptance by Conduct
Even where no explicit agreement on terms is reached, a contract may be concluded through conduct. In Brogden v Metropolitan Railway Company [1877], the parties had exchanged draft agreements but never formally signed them. The court held that by conducting themselves in accordance with the terms of the draft — by delivering and accepting coal under those terms — the parties had impliedly accepted those terms through their conduct. This principle operates distinctly from the counter-offer analysis: while the battle of the forms resolves which written terms prevail, acceptance by conduct addresses situations where behaviour demonstrates agreement regardless of formal documentation.
Uncertainty and the Court's Approach
Where negotiations produce an agreement that is too vague or leaves important matters undetermined, the courts may refuse to enforce it. In Scammell and Nephew Ltd v Ouston [1941], the House of Lords declined to enforce an agreement expressed to be "on hire-purchase terms" because the phrase was so ambiguous as to be meaningless without further agreement between the parties.
However, the courts will not too readily find an agreement void for uncertainty. Where a vague or general phrase can be given specific content by reference to all the surrounding circumstances or previous dealings, the court will strive to uphold the contract. In Hillas & Co Ltd v Arcos Ltd [1932], the House of Lords enforced an option clause that lacked precise specification, reading it in the context of the parties' broader commercial relationship and prior course of dealing.
General Rules of Acceptance
The Communication Principle
The general rule is that acceptance must be communicated to the offeror and is only effective when and where it is actually received. Until that point, no contract comes into existence. This principle was affirmed in Entores Ltd v Miles Far East Corporation [1955], where the Court of Appeal held that a contract made by telex between parties in different countries was formed at the place and time the acceptance was received by the offeror.
By Whom Must Acceptance Be Communicated?
Acceptance must be communicated by the offeree, or by a duly authorised agent acting on the offeree's behalf. It is insufficient for acceptance to be relayed by a reliable third party who has no authority from the offeree to communicate it. In Powell v Lee [1908], the claimant had applied for a position as headmaster. One of the board members, acting without authority, informed him that he had been selected. The court held that no contract had been formed: the communication had not been made by or on behalf of the offeree in any authorised capacity.
Silence as Acceptance
Silence will not, as a general rule, constitute acceptance. The offeror cannot impose a contract upon an unwilling offeree by stipulating that the offeree's failure to respond will be treated as acceptance. The purpose of this rule is to protect an offeree from being bound by a contract they did not intend to enter. In Felthouse v Bindley [1862], the claimant wrote to his nephew offering to buy his horse and stated that if he heard nothing more, he would consider the horse his at a specified price. The nephew said nothing, and the court held that no contract had been formed: silence could not amount to acceptance.
An exception may arise where the offeror has, by their own conduct, led the offeree to believe that silence will constitute acceptance, and the offeree has acted on that belief. In such circumstances, the offeree may be held to have accepted by remaining silent. This qualification was acknowledged in Re Selectmove Ltd [1995], though the courts have treated this exception narrowly, and the general position remains that silence cannot be acceptance.
The Postal Rule
The Principle
An important exception to the general communication rule applies where acceptance is made by post. Under the postal rule, a posted acceptance is complete and effective at the moment of posting, not when it is received by the offeror. The contract is therefore formed at the moment the letter of acceptance is placed in the post box. This rule was established in Adams v Lindsell [1818], in which the defendants had written to the claimants offering to sell wool and requesting a reply by post. The claimants posted their acceptance, but the defendants, not having received it promptly, had already sold the wool to a third party. The court held that the contract was formed on posting, and the defendants were therefore in breach.
Lost or Delayed Letters
The postal rule applies even where the letter of acceptance is subsequently lost or delayed in transit and never reaches the offeror. In Household Fire & Carriage Accident Insurance Company v Grant [1879], the defendant applied for shares in the company. A letter of allotment (which constituted acceptance) was posted to him but never arrived. The court held that a binding contract had nonetheless been formed on the posting of the letter, and the defendant was liable to pay for the shares.
Limitations of the Postal Rule
The postal rule is subject to important limitations. It applies only to acceptance, not to other communications such as an offer or a revocation of an offer — those are governed by the general receipt rule. The postal rule applies only where it was reasonable in all the circumstances to use the post as a means of communicating acceptance. Additionally, the letter of acceptance must be properly stamped, addressed, and posted; a carelessly or incorrectly addressed letter will not attract the benefit of the rule.
Excluding the Postal Rule
The postal rule may be expressly or impliedly excluded by the terms of the offer. If the language or circumstances of the offer make clear that the parties intended acceptance to be effective only upon actual communication to the offeror, the postal rule will not apply. In Holwell Securities Ltd v Hughes [1974], an option clause required acceptance to be made "by notice in writing to the intended vendor." The Court of Appeal held that this wording required actual communication of the acceptance and excluded the postal rule; posting the letter was therefore insufficient.
Retraction of a Posted Acceptance
There is no English authority definitively resolving whether a posted acceptance, once dispatched, can be retracted before the letter is received by the offeror. The question remains open in English law. Some academic commentary suggests that since the contract is formed at the moment of posting, any subsequent retraction would be ineffective and would itself constitute a breach. However, this point has not been conclusively settled by the courts.
Further Rules on Acceptance
Telexed and Instantaneous Communications
Where acceptance is transmitted by telex or other instantaneous means, the postal rule does not apply, and the general rule — that acceptance is effective upon receipt — governs. However, questions arise as to when, precisely, acceptance is "received" in the context of electronic communications. In The Brimnes [1975], the Court of Appeal held that a telexed notice was effective from the time it would reasonably have been expected to be read, even if the recipient did not actually read it until later. This introduced an element of objective reasonableness into the receipt rule.
Where acceptance is communicated by instantaneous means between parties in different locations, the question of when and where the contract is formed becomes important. In Brinkibon v Stahag [1983], the House of Lords confirmed that there is no universal rule for instantaneous non-postal communications. Instead, the court must consider the intentions of the parties, sound and established business practice, and the allocation of risk between the parties in all the circumstances of the case.
Acceptance in Unilateral Contracts
In a unilateral contract, the offeror makes a promise in exchange for the performance of a specified act by the offeree. No communication of an intention to accept is required; the offeree's performance of the stipulated act itself constitutes acceptance. The offeror is treated as having waived the need for prior communication of acceptance. This was confirmed in Carlill v Carbolic Smoke Ball Company [1893], where the company's advertisement promising £100 to anyone who used the smoke ball as directed and still contracted influenza was held to be an offer capable of acceptance by performance, without any prior notification to the company.
Acceptance in Offers of Reward
Where an offer takes the form of a reward, special considerations apply regarding the offeree's knowledge and motivation.
First, the offeree must be aware of the offer at the time they perform the act that constitutes acceptance. A person who performs the required act without any knowledge of the offer cannot be said to have accepted it, since there can be no assent without knowledge. This principle was applied in R v Clarke [1927], where the defendant had provided information leading to the arrest of murderers but had done so to clear his own name, having momentarily forgotten about the government's offer of reward. The court held that he could not claim the reward because, at the time of acting, he had no knowledge of, and therefore no intention to accept, the offer.
Second, where the offeree is aware of the reward offer, it is irrelevant that their motives for performing the act were mixed — that is, that they were partly motivated by reasons other than claiming the reward. The offeree is entitled to act for the reward alongside any other motives. This was established in Williams v Carwardine [1833], where the claimant gave information leading to the conviction of a murderer, motivated partly by personal reasons. The court held that she was nonetheless entitled to the reward, since she had knowledge of the offer and had performed the required act.