Offers and invitations to treat | AQA A-Level Law
For Specification 7162
AQA A-Level Law | Free Revision Notes
Estimated study time: 35–45 minutes
An enforceable contract requires agreement, so it is essential to distinguish a genuine contractual offer from an invitation to treat that merely invites another person to make an offer. This Offers and invitations to treat A-Level Law revision page also explains unilateral offers, where a promise is made in return for specified conduct rather than a reciprocal promise. The topic develops the nature of contract law [The nature of contract law] and provides the foundation for studying acceptance [Acceptance] and complete formation problems.
Learning Objectives 🎯
By the end of this revision page, you should be able to:
Define a contractual offer.
Explain the nature and purpose of an invitation to treat.
Distinguish an offer from an invitation to treat using the circumstances and wording of a communication.
Explain the nature of an offer in a unilateral contract.
Distinguish a unilateral offer from an ordinary invitation to treat.
Apply the distinction between offers and invitations to treat to factual scenarios.
Revision Notes 📚
Offers and invitations to treat A-Level Law revision
AQA requires students to analyse the voluntary nature of contract and, specifically, to understand the distinction between:
offers
offers in unilateral contracts
invitations to treat.
These concepts concern the creation of agreement.
An offer creates the possibility of a contract being formed through acceptance. An invitation to treat does not. It merely opens or continues the process by which offers may be made.
This distinction is therefore fundamental.
What is an offer?
An offer is a clear expression by one party of willingness to contract on specified terms, intended to become binding if accepted by the person or persons to whom it is addressed.
The person making the offer is the offeror.
The person to whom it is made is the offeree.
The basic sequence is:
offer → acceptance → agreement
Agreement is one of the essential requirements of formation, alongside consideration and intention to create legal relations.
The detailed rules governing what can happen to an offer are developed later in offer [Offer].
The intention to be bound
The important feature of an offer is that the offeror is indicating a willingness to be legally bound if the offer is validly accepted.
This distinguishes an offer from:
preliminary negotiations
a request for information
an invitation to another person to make an offer
a statement that merely provides information.
The court therefore has to determine the legal effect of the communication.
It is not enough simply to notice that:
a price has been mentioned
goods have been advertised
one party has expressed an interest in making a deal.
The key question is whether the communication shows that the person intended to make a proposal capable of acceptance.
What is an invitation to treat?
An invitation to treat is an invitation to another person to make an offer.
It is not itself an offer and therefore cannot normally be accepted to form a contract.
This distinction was expressly tested in AQA's specimen assessment material, where the accurate description of an invitation to treat was that it is an invitation to others to make an offer.
The usual sequence involving an invitation to treat is therefore:
invitation to treat → offer → acceptance → agreement
This differs from:
offer → acceptance → agreement
Why have invitations to treat?
The distinction gives a person or business an opportunity to receive an offer before becoming contractually committed.
Suppose a seller communicates information about an item but is not yet expressing a final willingness to be bound.
If that communication is an invitation to treat:
the potential buyer can make an offer
the seller can then decide whether to accept that offer.
If the seller's original communication were automatically treated as an offer, the seller could potentially become bound as soon as another person accepted it.
The classification of a communication therefore determines who makes the contractual offer and who has the power to accept it.
Offers and invitations to treat compared
Offer | Invitation to treat |
A proposal capable of acceptance | An invitation for another person to make an offer |
Shows willingness to be bound if validly accepted | Does not itself show a final willingness to be bound |
Acceptance may create agreement | A response normally takes the form of an offer |
The maker is the offeror | The person responding may become the offeror |
Can directly lead to a contract through acceptance | Normally begins or continues negotiations |
This distinction is especially important when examining advertisements and displays of goods.
Advertisements
An advertisement will often be treated as an invitation to treat rather than an offer.
The AQA mark scheme and examiner reports use Partridge v Crittenden as authority for this approach.
The general reasoning is that an advertisement may invite potential customers to make offers rather than demonstrate a final intention by the advertiser to be bound automatically.
However, this is not an absolute rule.
An advertisement may instead amount to a unilateral offer where its wording and circumstances show a sufficiently clear promise intended to be binding when the required act is performed.
This distinction is central to understanding Carlill v Carbolic Smoke Ball Co, an authority repeatedly identified in AQA assessment materials.
Displays of goods
A display of goods can also operate as an invitation to treat.
AQA assessment materials identify Fisher v Bell as relevant authority when distinguishing an invitation to treat from an offer.
The significance is the same:
the display invites the customer to make an offer
the seller may then determine whether that offer is accepted.
For examination purposes, avoid assuming that the mere presence of:
an item
a price
an advertisement
automatically means that a contractual offer has been made.
Context matters
The legal status of a communication depends on its wording and circumstances.
This is particularly important with advertisements.
AQA's 2025 mark scheme dealt with a newspaper advertisement offering a free car wash to customers who bought a specified amount of petrol. The mark scheme treated the precise wording and promise of a reward as evidence that the advertiser intended to be bound, making the advertisement a unilateral offer rather than merely an invitation to treat.
So the correct approach is not:
"All advertisements are invitations to treat."
Instead:
Advertisements will commonly be invitations to treat, but their wording and circumstances may demonstrate a genuine offer, including a unilateral offer.
What is a unilateral offer?
A unilateral offer involves a promise made in return for the performance of a specified act.
The structure is:
"If you perform this specified act, I promise to provide the stated benefit."
Unlike an ordinary bilateral agreement based upon an exchange of promises, a unilateral arrangement does not require the offeree to make a reciprocal promise.
AQA's 2025 examiner report emphasised this distinction. The defining characteristic of a unilateral contract is not simply that an offer is made to the world at large. Instead, the offer is accepted by performing the specified conduct, without the need for a reciprocal promise.
Promise in return for an act
The simplest way to remember a unilateral offer is:
promise in return for an act
For example, imagine that Noah states:
"I will pay £200 to anyone who finds and returns my missing watch."
No one receiving the offer has to promise:
"I will find your watch."
Instead, a person may choose whether to perform the requested act.
If someone performs the act required by the offer, that conduct can amount to acceptance.
This contrasts with a typical bilateral contract, which involves an exchange of promises.
Unilateral and bilateral agreements
Unilateral arrangement | Bilateral arrangement |
Promise is made in return for an act | Promise is made in return for another promise |
Offeree does not need to promise to perform | Parties exchange contractual promises |
Acceptance occurs through the required conduct | Acceptance normally takes the form of assent to the offer |
The offeree is generally free not to begin the act | Once the bilateral contract forms, both parties have obligations |
The distinction reflects the voluntary basis of contract considered in freedom of contract [Freedom of contract].
Carlill v Carbolic Smoke Ball Co
Carlill v Carbolic Smoke Ball Co is a key illustration of a unilateral offer in AQA assessment materials.
The case demonstrates that an advertisement can amount to an offer where its wording shows a sufficiently definite promise that can be accepted through the conduct specified.
The significance for your A-Level analysis is not simply to memorise:
"Carlill = advertisement."
Instead, use it to establish that:
an advertisement is not automatically an invitation to treat
sufficiently precise wording can indicate an intention to make an offer
the offer may be unilateral
acceptance can occur by performing the required act.
AQA repeatedly identifies Carlill as relevant authority when analysing whether an advertisement is an invitation to treat or a unilateral offer.
An offer to the world at large
A unilateral offer may be addressed to a large or indefinite group of people.
For example, an advertisement might promise a benefit to anyone who performs specified conduct.
However, this is not the defining characteristic of a unilateral offer.
AQA's 2025 examiner report specifically warned against defining unilateral contracts simply as contracts resulting from offers made to "the world at large".
The defining feature is:
the offeror promises something in return for specified conduct rather than a reciprocal promise.
An offer to the world at large is therefore one possible form of unilateral offer, not its essential definition.
Acceptance of a unilateral offer
A unilateral offer is accepted through conduct.
The offeree accepts by performing the act required by the offer.
For example:
Offer: "£500 reward to anyone who finds and returns my missing dog."
Acceptance: Finding and returning the dog in accordance with the offer.
The offeree does not normally need to make a separate promise to perform the act.
This becomes particularly important when studying acceptance [Acceptance] and the rules about communicating acceptance.
AQA's 2022 examiner report explained that, in a unilateral arrangement, the offer consists of a promise in return for an act and that communication of acceptance in the ordinary sense is unnecessary because acceptance occurs through completion of the required act.
The connection with voluntary contracting
Unilateral offers illustrate the voluntary nature of contract law particularly clearly.
The offeror makes a promise conditional upon specified conduct.
The offeree can choose:
to perform the conduct, or
not to do so.
The offeree is not normally contractually obliged merely because the offer exists.
This connects unilateral offers to freedom of contract [Freedom of contract]. The offeree can choose whether to perform the act required to accept the offer.
Starting performance and revocation
Unilateral contracts can create a particular difficulty.
What happens if the offeree begins the required act but has not yet completed it when the offeror attempts to withdraw the offer?
AQA assessment materials recognise this issue and identify Daulia v Four Millbank Nominees alongside Carlill when considering revocation of unilateral offers.
The 2025 examiner report also required students to consider whether beginning the required performance could prevent an offeror withdrawing a unilateral offer before the offeree had been given a reasonable opportunity to complete it.
The detailed rules governing revocation belong to the later substantive lesson offer [Offer]. At this stage, the essential point is that unilateral offers create special issues because acceptance is tied to performance of an act rather than a reciprocal promise.
Advertisement or unilateral offer?
This is a common examination problem.
Imagine an advertisement saying:
"Mountain bike for sale, £500."
This looks like an invitation for interested buyers to make offers.
Now compare:
"£500 reward to anyone who returns my stolen mountain bike."
The second statement is much more likely to be analysed as a unilateral offer because it contains:
a clear promise
a specified act
a benefit promised in return for completion of that act.
The key is therefore to analyse what the communication objectively appears to be doing.
A step-by-step approach
When faced with an advertisement or similar communication, use this sequence:
Identify the communication.
What exactly has been said or displayed?
Ask whether there is a clear commitment.
Does the person appear willing to be bound if the other party responds in the specified way?
Consider whether it merely invites offers.
If the communication begins negotiations rather than making a binding proposal, it is likely to be an invitation to treat.
Look for a unilateral promise.
Has the person promised a defined benefit in return for specified conduct?
Identify the legal consequence.
If it is an offer, ask whether it has been accepted. If it is an invitation to treat, identify who subsequently makes the offer.
This structure prevents one early mistake from undermining the rest of an answer.
Why the distinction matters
Misclassifying the original communication can change the legal analysis of everything that follows.
Suppose a seller's advertisement is an invitation to treat.
A buyer's response may then be the offer.
If instead the advertisement itself is an offer, the buyer's response may potentially be:
an acceptance
a counter offer
a request for information.
This is why identifying the starting point matters.
The 2023 examiner report praised stronger answers that considered whether an advertisement was an offer or invitation to treat before analysing the communications that followed.
Offers, invitations to treat and negotiations
Formation questions often involve a sequence of communications rather than a single statement.
The appropriate analysis may therefore be:
advertisement → response → further negotiation → final communication
For each stage, decide its legal status.
A strong answer might say:
the advertisement is probably an invitation to treat
the buyer's response may therefore constitute an offer
the seller's later statement must then be analysed to decide whether there has been acceptance.
This is much clearer than labelling communications independently without considering their relationship.
You will develop this method further in acceptance [Acceptance] before combining the formation rules in offer and acceptance problems [Offer and acceptance problems].
An important exam distinction
Do not confuse:
"an advertisement may be a unilateral offer"
with:
"all advertisements are unilateral offers."
Likewise, do not confuse:
"unilateral offers can be made to the world at large"
with:
"every offer made to the world at large is defined as unilateral merely because of its audience."
The key characteristic is the promise-for-an-act structure.
This distinction has been specifically highlighted in AQA examiner reports.
Key Words 🔑
Key word | Student-friendly definition | How it may be used in an exam |
Offer | A proposal showing willingness to be bound on specified terms if validly accepted. | Identify whether a communication gives another party the power to accept and create agreement. |
Offeror | The person who makes an offer. | Use when explaining which party has proposed contractual terms. |
Offeree | The person to whom an offer is made. | Use when identifying who may accept an offer. |
Invitation to treat | An invitation for another person to make an offer rather than an offer itself. | Use when analysing advertisements, displays and negotiations. |
Unilateral offer | A promise made in return for performance of a specified act rather than a reciprocal promise. | Use when analysing rewards or advertisements capable of acceptance through conduct. |
Hints from the Examiner Reports 💡
Examiner hint: Start by classifying the first communication. In 2023, weaker responses sometimes analysed a reply to an advertisement without first deciding whether the advertisement itself was an offer or an invitation to treat. This made the later analysis confused.
Examiner hint: Do not assume that every advertisement is an invitation to treat. The 2025 report praised students who recognised that a sufficiently clear and detailed reward advertisement could amount to a unilateral offer even though advertisements are commonly invitations to treat.
Examiner hint: Define unilateral contracts accurately. AQA specifically identified as an error the claim that their defining feature is simply an offer made to the world at large. The important characteristic is that acceptance requires specified conduct rather than a reciprocal promise.
Examiner hint: Keep the legal classifications consistent. If you conclude that an advertisement is only an invitation to treat, do not later describe the advertiser as revoking "the offer" unless you have explained where an offer subsequently arose. This inconsistency was identified in weaker 2025 responses.
Examiner hint: Consider reasonable alternative interpretations where the facts are genuinely uncertain. Stronger 2023 answers recognised that communications in negotiations may be capable of different legal interpretations and used those alternatives to reach reasoned conclusions.
Common Mistakes ⚠️
Mistake: Treating an invitation to treat as an offer
Why this is incorrect:An invitation to treat merely invites another person to make an offer. It cannot normally be accepted as though it were itself a contractual offer.
How to improve:Ask whether the maker has demonstrated a final willingness to be bound or has merely invited further negotiation.
Mistake: Saying all advertisements are invitations to treat
Why this is incorrect:Advertisements are commonly invitations to treat, but sufficiently precise wording may demonstrate a unilateral offer.
How to improve:Analyse the actual wording and ask whether there is a clear promise in return for specified conduct.
Mistake: Defining a unilateral offer as an offer to the world
Why this is incorrect:An offer may be made widely, but that is not what makes it unilateral.
How to improve:Remember:
Unilateral = promise in return for an act.
Mistake: Saying the offeree promises to perform a unilateral offer
Why this is incorrect:The unilateral structure does not depend upon the offeree making a reciprocal promise.
How to improve:Explain that acceptance occurs through the required conduct.
Mistake: Changing classifications halfway through an answer
Why this is incorrect:If the original advertisement is an invitation to treat, a later response cannot sensibly be described as a "counter offer" to that advertisement unless an actual offer already existed.
How to improve:Track the sequence carefully:
invitation to treat → offer → acceptance
or:
offer → acceptance.
Mistake: Giving a case name without explaining its relevance
Why this is incorrect:Legal authority should support your reasoning rather than replace it.
How to improve:Write the principle first and then use the case to support it, for example:
Partridge v Crittenden supports the usual treatment of advertisements as invitations to treat, whereas Carlill v Carbolic Smoke Ball Co demonstrates that sufficiently definite advertising can amount to a unilateral offer.
Exam-Style Questions ✍️
Question 1
Which one of the following best describes an invitation to treat?
A. An acceptance of a contractual offer
B. An invitation to another person to make an offer
C. A promise in return for an act
D. An offer that can only be accepted in writing
[1 mark]
Question 2
State two differences between an offer and an invitation to treat.
[2 marks]
Question 3
Explain what is meant by an offer in a unilateral contract.
[4 marks]
Question 4
Aisha advertises online:
"Vintage desk for sale, £300. Message me if interested."
Ben immediately messages Aisha stating, "I will buy the desk for £300."
Explain the possible legal significance of Aisha's advertisement and Ben's message.
[5 marks]
Question 5
Darius places the following notice in a community centre:
"£250 reward to anyone who finds and returns my missing camera."
Erin sees the notice and begins searching for the camera.
Explain why Darius's notice is capable of being treated differently from an ordinary advertisement offering goods for sale.
[5 marks]
Question 6
A shop displays a laptop beside a label showing a price of £750. Freya takes the laptop to the counter and says that she wishes to buy it for £750.
Using the distinction between offers and invitations to treat, analyse the formation issue raised by these facts.
[10 marks]
Question 7
Gareth publishes an advertisement stating:
"Free bicycle service for every customer who spends £150 or more in this shop during September."
Hannah sees the advertisement and spends £160 in the shop during September. Gareth later refuses to provide the free service.
Analyse whether the advertisement is more likely to be an invitation to treat or a unilateral offer.
[10 marks]
Question 8
Examine the distinction between an offer, an invitation to treat and an offer in a unilateral contract. Explain why correctly classifying a communication is important when deciding whether contractual agreement has been created.
[15 marks]
Answers and mark scheme
Question 1
Answer: B
An invitation to treat invites another person to make an offer.
1 mark
Question 2
Award 1 mark for each valid distinction, for example:
an offer is capable of acceptance, while an invitation to treat is not itself capable of acceptance to form agreement
an offer demonstrates willingness to be bound if accepted, while an invitation to treat invites another person to make the offer.
Maximum: 2 marks
Question 3
Indicative content:
A unilateral offer contains a promise.
The promise is made in return for performance of a specified act.
The offeree does not need to make a reciprocal promise.
Acceptance occurs through performing the required conduct.
Maximum: 4 marks
Question 4
Indicative content:
An advertisement of goods is commonly an invitation to treat rather than an offer.
Partridge v Crittenden may be used as supporting authority.
The wording "message me if interested" supports the view that Aisha is inviting responses rather than demonstrating a final commitment.
Ben's message may therefore constitute the offer to purchase the desk for £300.
A contract would require Aisha subsequently to accept that offer.
Maximum: 5 marks
Question 5
Indicative content:
An ordinary advertisement may be an invitation to treat.
Darius's notice contains a clear promise of £250.
The benefit is promised in return for a specified act, finding and returning the camera.
It therefore has the characteristics of a unilateral offer.
Carlill v Carbolic Smoke Ball Co may support the distinction.
Erin does not need to promise to find the camera for the arrangement to be unilateral.
Maximum: 5 marks
Question 6
Indicative content:
The display of the laptop may be treated as an invitation to treat.
Fisher v Bell may be used as relevant authority.
The display therefore invites customers to make offers.
Freya's attempt to buy the laptop may constitute the offer.
The shop would then need to accept the offer before contractual agreement arose.
A strong response should distinguish the shop's display from an offer capable of immediate acceptance.
The sequence of communication should be clearly identified.
Maximum: 10 marks
Question 7
Indicative content:
Advertisements are commonly invitations to treat, supported by Partridge v Crittenden.
However, that classification is not automatic.
Gareth's advertisement contains a specific promise, a free bicycle service.
It identifies the conduct required, spending at least £150 during September.
This resembles a promise in return for an act.
The arrangement may therefore be characterised as a unilateral offer.
Carlill v Carbolic Smoke Ball Co supports the possibility of an advertisement amounting to a unilateral offer.
Hannah has seen the offer and completed the conduct specified.
Her conduct may therefore amount to acceptance.
A substantiated conclusion should identify the advertisement as more likely to be a unilateral offer than an ordinary invitation to treat.
Maximum: 10 marks
Question 8
Indicative content may include:
an offer is a proposal capable of acceptance and showing willingness to be bound
an invitation to treat invites another party to make an offer
an invitation to treat therefore does not itself create the immediate possibility of agreement through acceptance
advertisements commonly operate as invitations to treat
displays of goods may operate as invitations to treat
classification depends upon the wording and circumstances
sufficiently definite advertisements may constitute offers
a unilateral offer is a promise in return for specified conduct
no reciprocal promise from the offeree is necessary
acceptance of a unilateral offer occurs through the required conduct
Partridge v Crittenden may illustrate an advertisement as an invitation to treat
Fisher v Bell may illustrate a display as an invitation to treat
Carlill v Carbolic Smoke Ball Co may illustrate an advertisement amounting to a unilateral offer
the initial classification determines who subsequently makes the offer and who has the ability to accept
misclassifying one communication can therefore undermine the analysis of the entire negotiation.
Higher-level answers should analyse communications as part of a logical sequence rather than simply defining the three concepts separately.
A substantiated conclusion should recognise that the distinction is fundamental because contractual agreement cannot be identified until the court determines whether there was first an offer capable of acceptance.
Maximum: 15 marks
Comments