The second city of the United Kingdom is an unofficial claim made at various times by several cities since the establishment of the Kingdom of Great Britain in 1707 (the United Kingdom was formed in January 1801). Commonly a country's second city is the city that is thought to be the second-most important, usually after the capital or first city according to criteria such as population size, economic importance and cultural contribution. The UK, in urban geography terms, has been classified as adhering to the primate city rule, meaning that the largest city in the nation outweighs every other city by orders of magnitude, London, the UK's capital, is by far the largest city, leaving other cities to be closer in prominence having been outshone by London, hence the competition for the 'Second City' of the UK is a rather subjective debate.