Gibbons v Proctor [1891] 64 LT 594 (also reported as Gibson v Proctor 55 JP 616), is an English contract law case that deals with an offer, via advertisement, and whether or not a person who doesn't know of the offer can accept the offer if he completes the conditions of the offer.
A police officer supplied information for which a reward had been offered; he was not aware of the offer at the time that he gave the information but he had become aware of the offer by the time the information reached the relevant party. It was held that the officer was entitled to claim the reward.
This case held that the advertisements of rewards for information leading to the arrest or conviction of the perpetrator of a crime, is treated as an offer, as the intention to be bound is inferred from the fact that no further bargaining is expected to result from them.
The case is sometimes wrongly cited as authority for the proposition that acceptance in ignorance of an offer is effective. A closer inspection of the facts of the case reveals that the party claiming the reward possessed full knowledge of the offer at the time when he gave the information.