"…The observation has often been made, that a contract established by letters may sometimes bind parties who, when they wrote those letters, did not imagine that they were finally settling terms of the agreement by which they were to be bound; and it appears to me that no such contract ought to be held established, even by letters which would otherwise be sufficient for the purpose, if it is clear, upon the facts, that there were other conditions of the intended contract, beyond and besides those expressed in the letters, which were still in a state of negotiation only, and without the settlement of which the parties had no idea of concluding any agreement [ My [Lloyd LJ's] emphasis] (4) Conversely, the parties may intend to be bound forthwith even though there are further terms still to be agreed or some further formality to be fulfilled (see Love and Stewart v. Instone per Lord Loreburn at p. 476). (5) If the parties fail to reach agreement on such further terms, the existing contract is not invalidated unless the failure to reach agreement on such further terms renders the contract as a whole unworkable or void for uncertainty. (6) It is sometimes said that the parties must agree on the essential terms and that it is only matters of detail which can be left over. This may be misleading, since the word "essential" in that context is ambiguous. If by "essential" one means a term without which the contract cannot be enforced then the statement is true: the law cannot enforce an incomplete contract. If by "essential" one means a term which the parties have agreed to be essential for the formation of a binding contract, then the statement is tautologous. If by an "essential" one means only a term which the Court regards as important as opposed to a term which the Court regards as less important or a matter of detail, the statement is untrue. It is for the parties to decide whether they wish to be bound and, if so, by what terms, whether important or unimportant. It is the parties who are, in the memorable phrase coined by the Judge "the masters of their contractual fate"