Lord Denning MR, in delivering the English Court of Appeal's decision in Amalgamated Investment & Property Co Ltd (in liquidation) v Texas Commerce International Bank Ltd [1981] 3 All ER 577, held that: "Course of dealing Although subsequent conduct cannot be used for the purpose of interpreting a contract retrospectively, yet it is often convincing evidence of a course of dealing after it. There are many cases to show that a course of dealing may give rise to legal obligations. It may be used to complete a contract which would otherwise be incomplete; see Brogden v. Metropolitan Railway (1877) 2 App. Cas. 666, 682, per Lord Hatherley. It may be used so as to introduce terms and conditions into a contract which would not otherwise be there: See (J. Spurling Ltd. v. Bradshaw [1956] 1 W.L.R. 461); Hardwick Game Farm v. Suffolk Agricultural Poultry Producers Association [1966] 1 W.L.R. 287, 308, 316, 317, C.A.; and [1969] 2 A.C. 31, 90, per Lord Morris of Borth-y-Gest, p. 104; per Lord Guest, and p. 113, per Lord Pearce, all disapproving the dictum of Lord Devlin in McCutcheon v. David MacBrayne Ltd. [1964] 1. All ER 430 at 437, [1964] 1 W.L.R. 125, 134, and Hollier v. Rambler Motors (A.M.C.) Ltd. [1972] 2 Q.B. 71, 77-78, per Salmon L.J. If it can be used to introduce terms which were not already there, it must also be available to add to, or vary, terms which are there already, or to interpret them. If parties to a contract, by their course of dealing, put a particular interpretation on the terms of it — on the faith of which each of them to the knowledge of the other acts and conducts their mutual affairs they are bound by that interpretation just as if they had written it down as being a variation of the contract. There is no need to inquire whether their particular interpretation is correct or not or whether they were mistaken or not or whether they had in mind the original terms or not. Suffice it that they have, by the course of dealing, put their own interpretation on their contract, and cannot be allowed to go back on it. To use the phrase of Latham C.J. and Dixon J. in the Australian High Court in Grundt v. Great Boulder Proprietary Gold Mines Ltd. (1937) 59 C.L.R. 641, 657, 677, the parties by their course of dealing adopted a "conventional basis" for the governance of the relations between them, and are bound by it. I care not whether this is put as an agreed variation of the contract or as a species of estoppel. They are bound by the "conventional basis" on which they conducted their affairs. The reason is because it would be altogether unjust to allow either party to insist on the strict interpretation of the original terms of the contract when it would be inequitable to do so, having regard to dealings which have taken place between the parties. That is the principle upon which we acted in Crabb v. Arun District Council [1976] Ch. 179, 187. It is particularly appropriate here where the judges differ as to what is the correct interpretation of the terms of the guarantee. The trial judge interpreted it one way. We interpret it in another way. It is only fair and just that the difference should be solved by the course of dealing by the interpretation which the parties themselves put on it and on which they conducted their affairs for years." (emphasis added)