 If the offeree were to convey acceptance by commercially unreasonable means – by cross-country pony express, for example – the acceptance would not be effective until it had actually been received.A letter is regarded as "posted" only when it is in the possession of the Post Office; this was established in the case of "Re London & Northern Bank" [1900] 1 Ch 220.A letter of acceptance is not considered "posted" if it is handed to an agent to deliver, such as a courier.