The notion of a loyal opposition exists in various Commonwealth realms, being therein termed formally as Her (or His) Majesty's Loyal Opposition and informally as the Official Opposition,[4] with the head of the largest opposition party—normally that which holds the second largest number of seats[4]—designated as the Leader of Her (or His) Majesty's Loyal Opposition. This tradition emerged in the oldest of the Commonwealth realms—the United Kingdom—during the 18th century.[2]