Gibson v Manchester City Council [1978] demonstrates the principles of offer and acceptance. An offer is an expression of willingness to contract to a legally binding agreement on certain terms made with the intention to commit to the agreement without further negotiation. An acceptance is made in response to an offer where the party agrees to the contractual term on a final and unequivocal basis. This must be externally manifested to ensure that the acceptance is valid – Tinn v Hoffman & Co (1873).