Tool Metal v Tungsten Electric

 D had to pay P royalties for creating and selling its product, and paying compensation when it produced in excess of a certain volume. The right to compensation was suspended during WWII and P tried to reinstate it in 1945. The HL ruled that “reasonable notice” had to be given in order to resume strict legal contractual rights. This was determined basically on account of what would be “equitable” i.e. fair.