Supervening Illegality Law and Legal Definition

Supervening illegality is when a statute or regulation or court decision makes the object of an offer illegal. It terminates the offer. A popular example is The best example is Avery v Bowden (1856), in which a ship was supposed to pick up some cargo at Odessa. With the outbreak of the Crimean War, the government made it illegal to load cargo at an enemy port, so the ship was excused from performing due to supervening illegality.