Agreement (Offer and Acceptance) (AQA A-Level Law): Revision Notes
Agreement (Offer and Acceptance)
Introduction
For a valid contract to exist under English law, there must be a legally binding agreement between the parties. This agreement is formed through two essential components: a valid offer followed by a valid, unconditional acceptance of that offer. Without both elements, no enforceable contract can come into existence.
This topic is assessed in Paper 1 of the A-Level AQA Law exam. Understanding the technical rules governing offer and acceptance is crucial, as these principles determine the precise moment when contractual obligations arise and which party bears legal responsibility.
The concepts of offer and acceptance form the foundation of contract law. Every contract, no matter how complex, begins with these two fundamental elements. Mastering the distinction between offers and invitations to treat, and understanding when acceptance is valid, is essential for success in contract law.
The offer
An offer is defined as an expression of one party's willingness to contract on certain terms, made with the intention that it will be legally binding upon acceptance. The offer sets out the proposed terms of the contract and indicates that the person making it (the offeror) intends to be bound by those terms if the other party (the offeree) accepts them.
The offeror typically communicates, either verbally or in writing, that they will be bound by the terms of the offer following valid acceptance and that they intend to create legal relations. Importantly, no contract is formed until the offeree accepts the terms contained in the offer.
Simple examples of offers include:
- "I will sell you my car for $5,000"
- "Do you want to buy my car for $5,000?"
In both examples, the offeror is making a clear statement of willingness to enter into a binding contract on the specified terms. The price, subject matter, and parties are all clearly identified, allowing the offeree to either accept or reject the proposal.
Invitation to treat
One of the most significant challenges in contract law is distinguishing between a genuine offer and what is legally termed an invitation to treat. While an offer creates the potential for an immediate binding contract upon acceptance, an invitation to treat is merely an invitation to others to make offers. It represents the preliminary stage of contractual negotiations where parties are invited to begin discussions or submit their own offers.
This distinction matters enormously in practice. If a shop display were classified as an offer, then simply picking up an item would constitute acceptance, creating an immediate binding contract. This would remove the shopkeeper's freedom to decide whether to sell and at what price. The law therefore protects commercial flexibility by classifying most preliminary commercial activities as invitations to treat rather than offers.
Goods on display in shops or on the internet
When goods are displayed on shop shelves or advertised online, this display does not constitute an offer to sell. The law treats such displays as invitations to treat. The rationale is straightforward: if the display were an offer, picking up an item would create immediate acceptance and form a contract, leaving the shopkeeper unable to refuse the sale.
Instead, the legal position is that the customer makes an offer to buy when they take the item to the till or checkout. At this point, the shopkeeper (or their representative) can choose whether to accept that offer, thus forming the contract. This principle was established in the leading case of Pharmaceutical Society of Great Britain v Boots Cash Chemists Ltd (1953).
Pharmaceutical Society of Great Britain v Boots Cash Chemists Ltd (1953)
Facts: The court had to determine whether controlled drugs displayed on self-service pharmacy shelves constituted offers (which would be a criminal offence) or invitations to treat.
Legal principle: The Court of Appeal held that the display was an invitation to treat. The contract was formed when the customer presented goods at the till and the pharmacist accepted the offer to purchase. This meant a qualified pharmacist could supervise the sale, satisfying the legal requirement.
The same principle applies to goods displayed in shop windows. The customer must enter the shop and make an offer to buy, which the shopkeeper can then accept or reject. This was confirmed in Fisher v Bell (1961), where a flick knife displayed in a shop window was held not to be an "offer for sale" (which was illegal) but merely an invitation to treat.
Goods or services advertised in newspapers, magazines and other media
Advertisements in newspapers, magazines, and other media are generally classified as invitations to treat rather than offers. The advertiser is inviting interested parties to come forward and make offers, which the advertiser can then choose to accept or refuse. This principle was established in Partridge v Crittenden (1968).
Partridge v Crittenden (1968)
Facts: Partridge was charged with the criminal offence of "offering for sale" wild birds after placing an advertisement in a newspaper.
Legal principle: The court held that his advertisement was an invitation to treat, not an offer to sell. Therefore, no offer had been made and no criminal offence was committed.
Exception: unilateral offers
There is an important exception to the general rule about advertisements. Where an advertisement takes the form of a reward or promise to pay for a specific action, it may be classified as a unilateral offer rather than an invitation to treat. A unilateral offer is one where acceptance occurs through performance of the specified act, rather than through communication.
The landmark case establishing this exception is Carlill v Carbolic Smoke Ball Co (1893).
Carlill v Carbolic Smoke Ball Co (1893)
Facts: The company advertised that they would pay $100 to anyone who used their smoke ball correctly but still caught influenza. They deposited $1,000 in the bank to show their sincerity. Mrs Carlill used the product as directed but caught influenza and claimed the $100 reward.
Legal principle: The Court of Appeal held that this advertisement was a unilateral offer to the world at large. It could be accepted by anyone who performed the conditions (using the product correctly). Mrs Carlill had accepted the offer through her conduct and was entitled to the $100. The company could not argue that the advertisement was merely an invitation to treat.
This exception applies to reward advertisements (such as for lost pets), promotional offers with clear conditions, and similar situations where the advertiser intends to be bound by their promise to anyone who fulfils the specified requirements.
Traditional coin-operated machinery
Historically, the courts developed special rules for coin-operated machinery such as car parking meters. In Thornton v Shoe Lane Parking (1971), the Court of Appeal held that the machine itself makes the offer, and inserting coins constitutes acceptance. This means the contract is formed at the moment the coins are inserted.
Legal significance: Any terms or conditions appearing on a ticket issued after the coins are inserted come too late to form part of the contract. This protects consumers from unfair terms that appear only after the contract has been concluded. However, this principle may be applied differently to modern automated systems where terms can be displayed before payment is made.
Communication of offers
A fundamental principle of contract law is that an offeree cannot accept an offer that has not been communicated to them. Without knowledge of the offer's existence, it is logically impossible to accept it. This requirement reflects the voluntary nature of contractual obligations – parties must knowingly agree to the terms that will bind them.
Taylor v Laird (1856)
Facts: Taylor had commanded Laird's ship but resigned from his command mid-voyage. He continued working on the ship as an ordinary crew member but did not communicate this change of role to Laird. Upon returning to England, Taylor attempted to claim wages for his work as crew.
Legal principle: The court held that Taylor could not claim wages because he had not communicated his offer to work as crew to the ship's owner. Without communication of the offer, there could be no acceptance and therefore no contract.
Termination of offers
An offer does not remain open indefinitely. There are four principal ways in which an offer can be terminated, after which it can no longer be accepted:
Counter-offers
When an offeree responds to an offer by proposing different terms, this constitutes a counter-offer. The legal effect of a counter-offer is twofold: it terminates the original offer and simultaneously creates a new offer in its place. The original offeree becomes the offeror of the counter-offer, and the original offeror can choose whether to accept or reject the new terms.
This is a critical distinction from a mere enquiry. If someone simply asks for information or clarification about an offer without proposing different terms, the original offer remains open for acceptance.
Hyde v Wrench (1840)
Facts: Wrench offered to sell his farm to Hyde for $1,000. Hyde responded with an offer to purchase for $950, which Wrench rejected. Hyde then attempted to accept the original offer of $1,000, but Wrench had sold the property to someone else.
Legal principle: The court held that Hyde's offer of $950 was a counter-offer that destroyed the original offer of $1,000. Once the counter-offer was made, the original offer ceased to exist and could no longer be accepted. Hyde had no valid claim.
Modern application: This principle operates commonly in online marketplaces such as eBay, where sellers may list items with a "Buy It Now or Best Offer" option. When a buyer makes a lower offer, this is a counter-offer. The seller can then accept, reject, or make their own counter-offer at a different price point.
Death of the offeror or offeree
The death of either party before acceptance terminates the offer. This reflects the personal nature of many contracts and the principle that acceptance must be communicated to a living offeror.
Lapse of time
An offer will lapse (expire) after a reasonable period of time if no time limit is specified, or after any specified time limit expires. What constitutes a "reasonable" period depends on the circumstances, including the nature of the subject matter and any relevant market conditions.
Ramsgate Victoria Hotel v Montefiore (1866)
Facts: Montefiore offered to buy shares in the hotel. The hotel company did not respond until six months later, by which time the share price had fallen significantly.
Legal principle: The court held that although the offer had not been formally withdrawn, six months was an unreasonably long time for an offer to remain open. The offer had lapsed through the passage of time and could no longer be accepted.
Revocation (withdrawal)
The offeror has the legal right to revoke (withdraw) their offer at any time before it is accepted. However, for revocation to be effective, it must be communicated to the offeree before acceptance takes place.
Dickinson v Dodds (1867)
Facts: Dodds offered to sell his house to Dickinson, stating the offer would remain open until Friday. On Thursday, Dodds sold the house to a third party and this information was communicated to Dickinson. Dickinson pretended not to know and attempted to "accept" the offer on Friday morning.
Legal principle: The court held that an offeror is free to withdraw an offer at any time before acceptance, even if they have promised to keep it open. There was no consideration from Dickinson to support the promise to keep the offer open until Friday, so the offer could be revoked earlier. Once Dickinson learned of the revocation (even indirectly), the offer was terminated and could not be accepted.
The acceptance
Once a valid offer exists, a contract is formed only when that offer is properly accepted. The acceptance must satisfy several requirements to be legally effective. These rules ensure certainty and clarity about when contractual obligations arise.
For acceptance to be valid, it must:
- Mirror the offer precisely – acceptance must be of the exact terms offered, with no variations
- Be unconditional – acceptance cannot be qualified or conditional
- Be communicated properly to the offeror – with limited exceptions, the offeror must receive notice of the acceptance
The requirement that acceptance must mirror the offer was confirmed in Sudbrook Trading Estate v Eggleton (1983), which emphasised that acceptance must be certain and unambiguous.
Acceptance must be unconditional
An acceptance must be absolute and unqualified. Any attempt to vary the terms, add conditions, or negotiate the offer will constitute a counter-offer rather than acceptance, as established in Hyde v Wrench (1840) discussed above.
However, merely making enquiries about the offer does not amount to a counter-offer and therefore does not prevent subsequent acceptance of the original terms.
Stevenson v McLean (1880)
Facts: McLean offered to sell Stevenson some iron, and Stevenson agreed on the price and quantity. Stevenson then enquired whether McLean would be willing to accept payment over four months rather than immediately in cash. Hearing nothing from McLean, Stevenson sent a letter accepting the original offer.
Legal principle: The court held that Stevenson's enquiry about credit terms was merely a request for information, not a counter-offer. The original offer remained open and could still be accepted. A contract was therefore formed when Stevenson accepted the original terms.
Exam technique: In problem questions, carefully distinguish between enquiries (which do not affect the offer) and counter-offers (which terminate the original offer). Look for language like "Would you consider..." or "I was wondering if..." which suggests an enquiry rather than a rejection and new proposal.
Battle of the forms
In commercial transactions, businesses frequently use standard form contracts containing their preferred terms and conditions. These forms are designed to protect the business's interests. Problems arise when two businesses attempt to contract with each other, each using their own standard terms.
When one company makes an offer on its standard form and the other company accepts on its different standard form containing conflicting terms, the question arises: which set of terms applies? This situation is known as the battle of the forms.
Butler Machine Tool Co Ltd v Ex-Cell-O Corp (1979)
Facts: Butler's standard form contract included a price variation clause allowing them to increase the price. Ex-Cell-O accepted the offer on their own standard form, which contained different terms and notably excluded any price variation clause.
Legal principle: The Court of Appeal held that Ex-Cell-O's response on their own standard terms was a counter-offer, not an acceptance. When Butler proceeded with the contract, they accepted Ex-Cell-O's terms. Therefore, Ex-Cell-O's terms applied, including the exclusion of the price variation clause. Lord Denning controversially suggested that in such cases, courts might imply reasonable terms to replace contradictory ones, though this approach has not been widely followed.
The general principle is that the "last shot" wins – whichever party last submits their terms before performance begins will have their terms incorporated into the contract.
Communication of the acceptance
A fundamental rule of contract formation is that acceptance must be communicated to the offeror. Only the offeree (the person to whom the offer was made) can make a valid acceptance. The contract is generally formed at the moment the offeror receives notice of the acceptance.
The principle that silence does not amount to acceptance protects offerees from having contracts imposed upon them. An offeror cannot say "If I don't hear from you by Friday, I'll assume you accept." The offeree must take positive action to accept the offer.
Acceptance can take various forms depending on the nature of the offer and any requirements specified by the offeror. It can be made through:
- Express words – spoken or written confirmation
- Conduct – performing the act requested in a unilateral offer (as in Carlill v Carbolic Smoke Ball Co)
- Specified method – if the offeror requires a particular method of acceptance, that method must be used
The postal rule
The postal rule represents an important exception to the general principle that acceptance must be communicated to the offeror. Under this rule, acceptance sent by post is effective when the letter is posted, not when it is received by the offeror.
Adams v Lindsell (1818)
Facts: The defendants wrote to the claimants offering to sell them a quantity of wool and requesting acceptance by post. The defendants' letter was incorrectly addressed, causing delay. When the claimants received the offer, they immediately posted their acceptance, but by this time the defendants had already sold the wool to a third party.
Legal principle: The court held that the contract was formed on the day the acceptance was posted, not when it was received. The defendants were therefore in breach of contract for selling to someone else after the contract with the claimants had been concluded.
Rationale: The postal rule exists for practical reasons. In an era before instantaneous communication, one party had to bear the risk of postal delay. The courts placed this risk on the offeror, as they chose to use the post and could protect themselves by specifying that acceptance must be received by a certain date.
Modern application and limitations:
The postal rule has faced scrutiny in the digital age. Recent High Court decisions have considered whether the rule should apply to modern communications:
Pretty Pictures v Quixote Films Ltd (2003): The court held that an exchange of emails would not amount to a binding contract where the parties clearly intended their agreement to be concluded by formal post.
Greenclose v National Westminster Bank plc (2014): The court suggested that emails should not be subject to an equivalent postal rule, implying that email acceptance would need to be received rather than merely sent.
The postal rule can also be excluded by the offeror's express terms. In Holwell Securities v Hughes (1974), the offer required that notice of acceptance be "received" by the offeror. This wording excluded the postal rule, meaning acceptance had to actually reach the offeror to be effective.
Electronic commerce: The Electronic Commerce Directive 2000 provides that in online consumer contracts, an offer is made when the consumer submits an order. The acknowledgement screen that appears typically constitutes acceptance, creating certainty about when the contract is formed.
Key cases summary
Offers
| Case | Facts | Legal principle |
|---|---|---|
| Pharmaceutical Society of Great Britain v Boots Cash Chemists Ltd (1953) | Court had to determine whether controlled drugs on self-service pharmacy shelves were offers (criminal offence) or invitations to treat | Display of goods is an invitation to treat. Contract forms when goods are presented at the till and accepted by the pharmacist |
| Fisher v Bell (1961) | Defendant displayed a flick knife in his shop window. Statute made it an offence to "offer for sale" such items | Display in shop window is an invitation to treat, not an offer for sale. No criminal offence committed |
| Partridge v Crittenden (1968) | Partridge charged with "offering for sale" wild birds (criminal offence) after placing newspaper advertisement | Advertisement is an invitation to treat, not an offer. No offer to sell had been made, so no offence |
| Carlill v Carbolic Smoke Ball Co (1893) | Company advertised $100 reward to anyone using their product correctly who still caught influenza. Mrs Carlill fulfilled conditions and claimed reward | Advertisement was a unilateral offer that could be accepted by anyone performing the specified conditions. Not merely an invitation to treat |
| Taylor v Laird (1856) | Ship's captain resigned mid-voyage but continued working as crew without communicating this to the owner. Later claimed wages | No contract formed because the offer to work as crew had not been communicated to the owner |
| Hyde v Wrench (1840) | Wrench offered farm for $1,000. Hyde counter-offered $950, which Wrench rejected. Hyde then tried to accept original $1,000 offer after property sold | Counter-offer of $950 destroyed the original offer of $1,000, which could no longer be accepted |
| Ramsgate Victoria Hotel v Montefiore (1866) | Montefiore offered to buy hotel shares. Six months later hotel accepted, but share price had fallen | Offer had lapsed through excessive passage of time. Six months was unreasonably long |
| Dickinson v Dodds (1867) | Dodds offered to sell house, promising to keep offer open until Friday. Sold to third party on Thursday and this was communicated to Dickinson | Offeror can withdraw offer any time before acceptance, even if promised to keep it open (without consideration for that promise) |
Acceptance
| Case | Facts | Legal principle |
|---|---|---|
| Stevenson v McLean (1880) | McLean offered to sell iron. Stevenson enquired about credit terms, then hearing nothing, accepted original offer | Enquiry for information does not constitute counter-offer. Original offer remained open for acceptance |
| Butler Machine Tool Co Ltd v Ex-Cell-O Corp (1979) | Butler's standard form included price variation clause. Ex-Cell-O accepted on their own standard form with conflicting terms | In battle of the forms, the last set of terms submitted before performance constitutes a counter-offer. Proceeding with performance accepts those terms |
| Adams v Lindsell (1818) | Defendants offered wool by post. Their letter was misdirected, causing delay. Claimants posted acceptance same day but defendants had sold wool | Under postal rule, acceptance is effective when posted, not when received. Contract formed when acceptance posted |
Use these case tables as a quick reference guide for revision. Each case establishes a key principle that you should be able to explain and apply in exam questions.
Key Points to Remember:
- A valid contract requires both a valid offer and valid acceptance – without both elements, there is no enforceable agreement
- Distinguish offers from invitations to treat – shop displays, advertisements, and goods in windows are usually invitations to treat, not offers; exceptions exist for unilateral offers like rewards
- Counter-offers terminate the original offer – they cannot be "revived" later; mere enquiries do not have this effect
- Acceptance must mirror the offer exactly – any variation creates a counter-offer rather than acceptance
- The postal rule makes acceptance effective when posted, not received – but this can be excluded by the offeror and may not apply to modern electronic communications
- Communication is essential – offers and acceptances must generally be communicated to be effective (with the postal rule exception)
- Master your case law – key cases like Carlill, Hyde v Wrench, Boots, and Partridge v Crittenden form the foundation of examination answers