Postal Rule

Postal rule of acceptance which is also known as the 'postal rule' or 'mailbox rule' is a rule stated that the acceptance is effective upon posting if postal service is an acceptable method of communication between the offeror and offeree. Postal acceptance rule is in contrast with the general rule where acceptance is only valid when it is communicated to the offeror, in other word, receipt of the acceptance by the offeror. Nevertheless, some of the issues relevant to this rule need to be reconsidered such as application of postal rule in this modern century and the scope of communications method that should be covered by postal acceptance rule.

First of all, postal rule is applied when postal service is the method used by offeror to make offer for the offeree. It was held in Henthorn v Fraser that:

The offeror must be considered as having made the offer throughout the whole time that his offer is in the post, and that therefore, the agreement between the parties is complete as soon as the acceptance is posted.

Besides that, it will also be applied when it is stated by the offeror in the contract that acceptance can be done using the postal rule or other method of communication. Since the acceptance of the offer is completed as soon as the letter of acceptance is posted, it is irrelevant of whether the acceptance is delayed or fail to reach the offeror.

There are four justifications for postal acceptance rule and the first one which is the "Ad Infinitum" justification is shown in the case of Adams v Lindsell where the court has to decide on the time of contract formation by post. In Adams v Lindsell, it adopted the rule to avoid "extraordinary and mischievous". The court held that:

If the defendants were not bound by their offer when accepted by the plaintiffs till the answer was received, then the plaintiffs ought not be bound till after they had receive the notification that the defendants had received their answer and assented to it. And so it might go on, ad infinitum.

The court favours Adam in their decision as it is very unfair if the court allows Lindsell to revoke from honouring the contract which would have be binded if Lindsell did not misaddressed the offer. Besides that, the "Symbolic Act" justification says that offeror should continue making his or her offer until he is acknowledged that his or her acceptance has been withdrawn by the offeree thru posting. In addition, the "Evidential Difficulties" justification states that it is more difficult to prove the receipt of acceptance letter compared to the letter sent as the offeror might lies upon the receipt of acceptance. Lastly, the "Common Agent" justification states that the post office as the agent for the offeror and offeree. Once the letter is posted to the post office, the contract is said to be completed as the acceptor has