(a) Advise Mr. Robert whether his revocation of offer by post is effective as against Mr. James.

The issue in the given situation is whether Mr. Robert's revocation of offer by post is effective or not as against Mr. James.

Section 2(h) of the Contract Act 1950 defines that contract is an agreement enforceable by law. In order for an agreement to be enforceable by law, it must consist of six essential elements which are offer, acceptance, consideration, intention to create legal relation, capacity and certainty. The revocation of proposal is define in Section5(1) Contracts Act as a proposal may be revoked at any time before the communication of its acceptance is complete as against the proposer, but not afterwards. In order for the revocation of the proposal to be effective, it must be communicated by the proposer to the other party before it accepts. Communication of revocation can be done by the proposer or his agent acting on his behalf. In the event of acceptance by post or telegram, the acceptance is complete as against the proposer upon posting or delivery of the telegram.

In the case of Byrne v. Tienhoven, defendant posted letter of offer to the plaintiff on 1 October. On 8 October, defendant posted a letter revoking the offer. On 11 October, plaintiff received the letter of offer and sent acceptance by telegram on the same day. Only on 20 October did the defendant's letter of revocation was received by the plaintiff. The court held that there is a contract between the parties. Revocation of the offer was not effective till 20 October when it was received by the plaintiff. But in the meantime, the latter had already accepted the offer on 11 October when the telegram was sent.

In the situation of Mr. Robert and Mr. James, the revocation of the offer posted by Mr. Robert on 9 July 2012 was not effective till 20 July 2012 when it was receive by Mr.