Offer and acceptance — common mistakes

In problem questions, always begin by determining if a statement is a firm offer or an invitation to treat. Use the objective test of intention: would a reasonable person believe the maker of the statement intended to be bound? Quote key cases like Gibson v Manchester City Council for lack of certainty and Partridge v Crittenden for advertisements.

In timeline-based scenarios, pinpoint the exact moment revocation is communicated. The postal rule does NOT apply to revocation. A letter of revocation is only effective when it arrives with the offeree, not when it is posted.

Be careful to distinguish a counter-offer from a request for information. A counter-offer introduces new terms ('I will pay £900 instead of £1000'), whereas a request for information seeks clarification ('Does the price include delivery?'). This distinction is critical to determining if the original offer is still open for acceptance.

In a problem question involving different communication methods, create a timeline. Identify if the communication is postal or instantaneous. Apply the Adams v Lindsell rule for post and the Entores 'receipt' rule for everything else. This will determine the precise moment a contract is formed.

Generally, yes. The case of Partridge v Crittenden established that advertisements are usually invitations to treat to avoid the seller being bound by more contracts than they can fulfil. However, there is a key exception. If the advertisement is for a 'unilateral' contract and shows a clear intention to be bound (e.g., by stating that a reward will be given for performing an act), it can be an offer to the whole world, as seen in Carlill v Carbolic Smoke Ball Co.

No, this is a common misconception. The postal rule applies only to letters of acceptance, not to letters of revocation. For a revocation to be effective, it must be actually communicated to and received by the offeree. This was established in Byrne v Van Tienhoven. Therefore, if an offeree posts their acceptance before they receive the letter of revocation, a valid contract is formed.

A counter-offer changes the material terms of the original offer and, in doing so, destroys it (Hyde v Wrench). For example, 'I'll buy your car for £8,000' in response to an offer of £10,000. A request for more information, however, merely seeks to clarify the terms of the offer and leaves the original offer intact and open for acceptance (Stevenson, Jacques & Co v McLean). For example, 'Would you accept payment in instalments?' This is a crucial distinction in determining whether a contract can still be formed on the original terms.