An agreement is a far-reaching approach that involves any agreement or agreement between two or more parties on their rights and obligations. Such informal agreements often take the form of ”gentlemen`s agreements”, in which compliance with the terms of the agreement is based on the honour of the parties concerned and not on external means of implementation. A related doctrine is a ”common error” which, since Lord Phillips MR`s decision in The Great Peace, is much the same in the company as frustration, except that the event that renders a contract impossible occurs before and not after the conclusion of a contract.  A ”common error” differs from ”mistakes” that occur between offer and acceptance (i.e., there is no agreement) or so-called ”identity error” cases resulting from fraudulent misrepresentation (which generally invalidates a contract, unless it is concluded in a written and remote document) because it is based on the fact that performance is seriously difficult to achieve. For example, at Courturier v Hastie, a shipment of corn had elapsed when two businessmen had entered into a contract, so it was established (perhaps controversial) that the seller was not responsible because it was still physically impossible. In Cooper v Phibbs, the House of Lords found that a fishing lease agreement was void because it turned out that the tenant was indeed the landlord. It is legally impossible to get what you have. Here too, the doctrine of general error can be circumvented, so that the McRae v Commonwealth Disposals Commission found that despite the fact that a destroyed ship never existed before the Great Barrier Reef, because a rescue operation was in fact promised by the Australian government that it was there, there was no common error. How frustration teaching only works within narrow limits. In Bell/Lever Bros Ltd, Lord Atkin stated that an error ”must be of such a fundamental nature that it constitutes an underlying presumption without which the parties would not have entered into the agreements.” After the war, Denning LJ added to the doctrine beyond its narrow legal limits, in accordance with the more permissive approach that is recognized in all civil law countries, most of the Commonwealth and the United States.
In Solle v Butcher, he held that a contract could be considered non-sharp (and not without rights) if it was ”indecent” that a court would keep someone on a good deal.