G.K. Chesterton 
Napoleon of Notting Hill [PDF ebook] 

A satire set in a future England, in which a neomedievalist contest among London neighborhoods takes a disastrous turn.When Auberon Quin, a prankster nostalgic for Merrie Olde England, becomes king of that country in 1984, he mandates that each of London’s neighborhoods become an independent state, complete with unique local costumes. Everyone goes along with the conceit until young Adam Wayne, a born military tactician, takes the game too seriously. . . and becomes the Napoleon of Notting Hill. War ensues throughout the city-fought with sword and halberd!