AQA A-Level Law: Contract Law Key Cases You Must Know
Contract law is one of the Paper 2 options on the AQA A-Level Law specification, and it has a wonderfully logical structure: formation, then terms, then vitiating factors, then remedies. At every stage the law is built from cases — many of them very old, and all of them still cited. Examiners reward students who can name the right authority, state its principle in a sentence, and apply it to the facts. This guide presents the essential contract law cases you need to know, organised by topic.
Bookmark this page, print it out, or turn it into flashcards. However you learn best, make sure every one of these cases is at your fingertips before you walk into the exam.
For full interactive revision of contract law, see our course: AQA A-Level Law: Contract Law.
Offer and Invitation to Treat
A contract begins with a valid offer. The first task is usually distinguishing a genuine offer from an "invitation to treat" — an invitation for others to make offers.
1. Carlill v Carbolic Smoke Ball Co [1893]
A company advertised that it would pay £100 to anyone who used its smoke ball as directed and still caught influenza, stating it had deposited money in a bank to show its sincerity. Principle: An advertisement can amount to a unilateral offer to the whole world, accepted by performance of the stated conditions. The deposited money showed an intention to be bound, and no separate communication of acceptance was needed.
2. Partridge v Crittenden [1968]
A magazine advertisement read "Bramblefinch cocks and hens, 25s each." Principle: An advertisement of goods for sale is generally an invitation to treat, not an offer. This protects sellers from being bound to sell to every reader where stock is limited.
3. Fisher v Bell [1961]
A shopkeeper displayed a flick knife in his window with a price ticket; he was charged with "offering for sale" an offensive weapon. Principle: Goods displayed in a shop window are an invitation to treat, not an offer for sale. The display invites the customer to make an offer to buy.
4. Pharmaceutical Society of Great Britain v Boots [1953]
Goods, including regulated medicines, were displayed on the shelves of a self-service shop. Principle: Displaying goods on a shelf is an invitation to treat. The customer makes the offer at the till, which the retailer may accept or reject. This determined where in the transaction the contract is formed.
Acceptance and the Postal Rule
Acceptance must be a final, unqualified agreement to the terms of the offer, and it must generally be communicated.
5. Hyde v Wrench [1840]
An offer to sell a farm for £1,000 was met with a counter-offer of £950, which was rejected; the buyer then tried to accept the original £1,000. Principle: A counter-offer destroys the original offer, which can no longer be accepted. A counter-offer is a rejection coupled with a fresh offer.
6. Adams v Lindsell [1818]
An offer sent by post was accepted by return of post, but the acceptance letter was delayed in reaching the offeror. Principle: The "postal rule" — where acceptance by post is reasonable, the contract is formed at the moment the letter is properly posted, not when it is received. This is an exception to the general rule that acceptance must be communicated.
7. Byrne v Van Tienhoven [1880]
An offer was posted, then a revocation was posted before the offeree accepted, but the revocation arrived after the offeree had already accepted. Principle: Revocation of an offer is only effective when it is actually communicated to (received by) the offeree. The postal rule does not apply to revocation, so the late-arriving withdrawal came too late.
Consideration
For a promise to be enforceable (outside a deed), it must be supported by consideration — something of value given in return.
8. Currie v Misa [1875]
A case concerning the meaning of value exchanged between parties. Principle: Consideration was defined as some right, interest, profit, or benefit accruing to one party, or some forbearance, detriment, loss, or responsibility given, suffered, or undertaken by the other. This is the classic definition of consideration.
9. Stilk v Myrick [1809]
Sailors were promised extra wages to sail a ship home after two of the crew deserted. Principle: Performing an existing contractual duty is not good consideration for a fresh promise. The remaining sailors were already bound to sail the ship, so the promise of extra pay was unenforceable.
10. Williams v Roffey Bros and Nicholls [1991]
A subcontractor in financial difficulty was promised extra payment by the main contractor to finish carpentry work on time. Principle: Where one party gains a "practical benefit" (such as avoiding a penalty for late completion or the cost of finding a replacement) from the other's completion of an existing duty, that practical benefit can amount to good consideration — provided the promise was not given under duress. This refined Stilk v Myrick.
11. Pinnel's Case (1602)
A creditor accepted part-payment of a debt before the due date in purported satisfaction of the whole. Principle: Payment of a smaller sum cannot by itself satisfy a debt for a larger sum (the rule that part-payment is not good consideration for a promise to forgo the balance), although doing something different — such as paying early or adding a chattel at the creditor's request — may.
12. Foakes v Beer [1884]
A creditor agreed to accept payment of a judgment debt by instalments but later claimed the interest that had accrued. Principle: The House of Lords affirmed the rule in Pinnel's Case — an agreement to accept part-payment of a debt is not binding for want of consideration, so the creditor could still claim the balance (the interest).
Promissory Estoppel
Equity can, in limited circumstances, prevent a party from going back on a promise even without consideration.
13. Central London Property Trust v High Trees House [1947]
A landlord promised to accept reduced ground rent during wartime when flats were hard to let, then later sought to recover the full rent. Principle: The doctrine of promissory estoppel — where a party makes a clear promise intended to be relied upon, and the other relies on it, the promisor may be prevented (estopped) from going back on that promise where it would be inequitable to do so. It generally suspends rights rather than extinguishing them and is "a shield, not a sword."
Intention to Create Legal Relations
Even with offer, acceptance, and consideration, there is no contract unless the parties intended to be legally bound.
14. Balfour v Balfour [1919]
A husband promised his wife a monthly allowance while he worked abroad; the marriage later broke down. Principle: Domestic and social agreements are presumed not to be intended to create legal relations. The arrangement between the spouses was not a legally binding contract.
15. Merritt v Merritt [1970]
A separated couple made a written agreement about the matrimonial home and mortgage payments. Principle: The presumption against legal relations in domestic agreements can be rebutted. Where spouses are separating (rather than living in amity) and make a clear, often written, agreement, the courts will usually find an intention to be legally bound.
Contract Terms
Terms may be classified by importance, which determines the remedy for breach.
16. Hong Kong Fir Shipping v Kawasaki Kisen Kaisha [1962]
A ship was chartered but its unseaworthiness and crew problems caused delays; the charterers purported to terminate. Principle: Some terms are "innominate" — neither plainly conditions nor warranties. The remedy depends on the seriousness of the consequences of the breach: only if the breach deprives the innocent party of substantially the whole benefit of the contract may they treat it as repudiated. This introduced the innominate term.
Exclusion Clauses and Consumer Protection
The law controls clauses that try to exclude or limit liability, both through common-law rules of incorporation and through statute.
17. L'Estrange v Graucob [1934]
A buyer signed a contract for a vending machine containing an exclusion clause in small print, without reading it. Principle: A person is bound by the terms of a contractual document they have signed, whether or not they have read it (absent misrepresentation or fraud). This is the general rule on incorporation by signature.
18. Consumer Rights Act 2015
A statute consolidating consumer protection. Principle: The Consumer Rights Act 2015 implies key terms into consumer contracts — that goods are of satisfactory quality, fit for purpose, and as described, and that services are performed with reasonable care and skill. It also subjects unfair terms (including many exclusion clauses) to a fairness test in contracts between traders and consumers. (Cite the statute rather than a case for these protections.)
Vitiating Factors
Vitiating factors undermine an apparently valid contract, rendering it void or voidable.
19. Bell v Lever Bros [1932]
An employer paid generous compensation to terminate executives' service contracts, unaware the executives had committed breaches that would have justified dismissal without payment. Principle: A common mistake renders a contract void only where it relates to something fundamental — a quality so essential that it makes the thing contracted for essentially different from what the parties believed. The mistake here was not fundamental enough, so the contract stood.
20. Derry v Peek [1889]
Company directors honestly but wrongly stated in a prospectus that they had the right to run steam trams. Principle: Fraudulent misrepresentation requires a false statement made knowingly, or without belief in its truth, or recklessly as to whether it is true or false. An honest (if careless) belief in the statement's truth is not fraud. This defines fraudulent misrepresentation.
21. Misrepresentation Act 1967
A statute governing remedies for misrepresentation. Principle: The Misrepresentation Act 1967 provides remedies for negligent and innocent misrepresentation. Under s.2(1) a claimant may recover damages for a misstatement unless the maker proves they had reasonable grounds to believe, and did believe, it was true; under s.2(2) the court has discretion to award damages in lieu of rescission. (Cite the statute for these remedies.)
Remedies for Breach
Where a contract is breached, the innocent party is entitled to a remedy — most often damages.
22. Hadley v Baxendale [1854]
A mill's broken crankshaft was delayed in carriage; the mill claimed lost profits during the resulting shutdown, which the carrier did not know about. Principle: The remoteness rule for contract damages. Recoverable losses are those arising naturally from the breach (in the ordinary course of things), or those which both parties could reasonably have contemplated, at the time of contracting, as a probable result of the breach. Unusual losses are recoverable only if the special circumstances were known.
23. Ruxley Electronics v Forsyth [1996]
A swimming pool was built slightly shallower than specified, but the shortfall did not affect its usability or value, and rebuilding would cost a fortune. Principle: Where the cost of fixing a defect is wholly disproportionate to the benefit obtained, damages are not assessed at the full cost of cure. The court instead awarded a modest sum for "loss of amenity," reflecting the claimant's disappointed expectation.
24. Cavendish Square Holding v Makdessi [2015]
A commercial contract contained clauses imposing financial consequences on a party who breached restrictive covenants. Principle: The Supreme Court restated the test for penalty clauses. A clause is an unenforceable penalty only if it imposes a detriment on the contract-breaker out of all proportion to any legitimate interest of the innocent party in enforcement. This is the modern penalty test, moving beyond the old "genuine pre-estimate of loss" formula.
How to Use These Cases in the Exam
Knowing the cases is only half the battle — you must also use them effectively in your exam answers.
In scenario (problem) questions, follow the structure of contract law and cite a case at each step. For example: "First, is there a valid offer? The price list is likely an invitation to treat (Partridge v Crittenden [1968]), so the customer's order is the offer. Was it accepted? A counter-offer would destroy the original offer (Hyde v Wrench [1840])..."
In essay questions, use cases as evidence to support evaluation. For example: "The recognition of 'practical benefit' in Williams v Roffey Bros [1991] arguably softened the rigidity of Stilk v Myrick [1809], though it sits uneasily with the part-payment rule preserved in Foakes v Beer [1884]."
General tips for citing cases:
- Always give the case name and date. You do not need the full law-report citation.
- State the principle concisely — one sentence is usually enough.
- Apply the principle to the facts of the scenario. This is where the marks are.
- Where cases show the development of a principle (such as Stilk and Williams v Roffey), explain the relationship between them.
- Where the law is statutory (Consumer Rights Act 2015, Misrepresentation Act 1967), cite the Act and the relevant section rather than inventing a case.
Revise Smarter with LearningBro
This list covers the cases that appear most frequently in AQA A-Level Law contract questions and mark schemes. If you can recall and apply every one of these cases, you will have a significant advantage.
For full interactive revision of contract law — with hundreds of practice questions, instant feedback, and topic-by-topic coverage — explore our course: AQA A-Level Law: Contract Law.