The advertisement Bert placed in the newspaper announcing a ‘quiz night on Saturday with £1000 cash for the winner’ is construed as a unilateral offer. Advertisements are usually considered invitations to treat whereby the person making the invitation is free to accept or reject any offers made, thus not being bound.
However, in this case Bert’s advertisement should be considered unilateral. This is because the advertisement indicates that the advertiser i.e. Bert promises to pay £1000 in return for the performance of an act which is winning the pub quiz. Bert is therefore bound to give £1000 upon performance of the required act provided there is consideration and intention to create legal relations.
Perhaps the best authority for this situation is the case of Carlil v. Carbollic Smoke Ball Company Ltd  1QB256 which concerned a unilateral offer made in an advertisement. It was held that advertisement was in fact a unilateral offer whereby the defendants where bound as the required acts had been performed.
Furthermore, acceptance must be made in response to an offer particularly regarding unilateral offers as these offers are made to a large audience. The requested act which in this case is to win the pub quiz must be performed in order for it to be considered an acceptance of the offer. The requested performance constitutes the acceptance and the consideration. As Alfie and Jerry didn’t actually take part in the quiz, there is no acceptance as in Daulia Ltd v. Four Millbank Nominees Ltd, where the offer could only be accepted by fully performing the stipulated act and no less.
An offer may be revoked at any time prior to acceptance which in this case, did not happen. This is supported by the case Routledge v. Grant  4 Bing 653. In this situation the performance of the quiz was prevented due to the quiz being cancelled. It is up to the offeror i.e. Bert to revoke the offer at any time before the offerree i.e Alfie and Jerry can complete...