Southern Foundries (1926) Ltd v Shirlaw
Southern Foundries (1926) Ltd v Shirlaw [1940] AC 701 is an important English contract law and company law case. In the field of contracts it is well known for MacKinnon LJ's decision in the Court of Appeal, where he put forth the "officious bystander" formulation for determining what terms should be implied into agreements by the courts.
Source: Wikipedia — Southern Foundries (1926) Ltd v Shirlaw (CC BY-SA 4.0)