Offer and acceptance — FAQ

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.