Identify agreements and contractual promises
Distinguish a bargain exchanging promises from a promise accepted by an act and a separate collateral undertaking.
Exam scope and assessment notes
A Level · section 3.1.1. Original educational scenarios about the law of England and Wales, checked on 14 October 2026. Model answers are formative reasoning, not advice about a real dispute, Cambridge marks or predicted grades. Read the exact statute, case and exam-year source where a rule is disputed or changes. A larger annotated authority bank, full unseen papers and specialist law-teacher review remain outstanding.
Before you begin
- Read a short source carefully and separate its rule from the facts
- Explain which element a fact supports and what is still uncertain
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What should a legal problem answer connect?
What you will learn
- Explain bilateral, unilateral and collateral contracts
- Apply objective agreement without assuming every promise is enforceable
Identify the exchange
In a bilateral contract each party undertakes an obligation: a supplier promises delivery and a buyer promises payment. In a unilateral contract one party promises a reward or other performance in exchange for a specified act. Completing that act can accept the offer; merely saying ‘I might do it’ need not do so. An agreement still needs the other applicable formation requirements, including consideration, intention and capacity.
A collateral contract is a separate contractual promise that induces entry into the main contract. Identify its maker, promise, consideration and relationship to the main terms. A statement about a product is not automatically a second contract: it might instead be a term, representation or non-binding sales talk.
Use observable agreement
The court ordinarily asks what words and conduct objectively communicate in context, rather than either party's unexpressed private intention. Signing is important evidence but is not a universal requirement for every type of contract. RTS illustrates why conduct and the actual negotiations matter even when a formal document has not been completed.
Certainty and any applicable formalities still matter. A vague expression of future cooperation is different from settled obligations. In an answer, write who promised what, how the agreement was accepted and which requirement remains disputed before considering a remedy.
Sources for this lesson
Pause and explain
Does a unilateral offer necessarily require a promise to perform as its acceptance?
Worked example
A fictional notice promises £40 to anyone who returns a specified lost folder. Jo returns it in accordance with the notice. Classify the exchange.
Show the worked solution
- The notice promises payment for an act.
- Returning the specified folder is the requested act.
- Check the notice's conditions and remaining formation requirements.
Answer This is the structure of a unilateral reward contract: acceptance is by the requested performance, rather than an exchange of promises to search and pay. Compliance with the notice and the remaining requirements still need to be established.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Guided: Identify the promise and act in the folder example.
Give me a hint
Separate the two sides of the exchange.
Compare my reasoning
- The maker promises £40.
- Jo performs the specified return.
- Check compliance with the notice.
The maker's payment promise is exchanged for returning the specified folder. Jo's completed act can accept that unilateral offer if its conditions and the other contractual requirements are met.
Look for these in your work
- Names the promise
- Names the act
- Checks conditions
Independent: A supplier promises ten chairs on Friday and the buyer promises £200. Classify this arrangement.
Give me a hint
Ask whether each side undertakes an obligation.
Compare my reasoning
- Identify delivery obligation.
- Identify payment obligation.
- Distinguish promises from a reward accepted only by an act.
The arrangement has the structure of a bilateral contract because each side makes a promise. That classification does not dispense with agreement, certainty, consideration, intention or capacity.
Look for these in your work
- Identifies both obligations
- Uses bilateral
- Preserves formation requirements
Application: Before a lease is signed, the owner makes a precise repair promise to induce the tenant to sign. What must a collateral-contract argument establish?
Give me a hint
A separate statement is not automatically a separate bargain.
Compare my reasoning
- Identify the promise and its maker.
- Connect signing the main contract to consideration for it.
- Check intention and compatibility with the main agreement.
The argument must establish a sufficiently certain contractual promise, consideration through entry into the main agreement, intention and its relationship to the lease. An inducement may support the analysis, but does not by itself turn every representation into a collateral contract.
Look for these in your work
- Identifies separate promise
- Explains consideration
- Examines main terms
Common mistakes
- Treating every promise as a contract
- Calling all contracts bilateral
- Assuming no signature means no agreement
What can you explain now?
Does a unilateral offer necessarily require a promise to perform as its acceptance?
Compare with the explanation
No, the requested act can constitute acceptance
Identify whether the offer requests a promise or completed performance.
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Make it stick
Does a unilateral offer necessarily require a promise to perform as its acceptance?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.