Their chequered history began in India and China, 3,000 years ago, when flags were the badges of emperors and the calling cards of conquering armies, paraded in battle and raised above the ramparts of captured cities. They would often depict objects or animals, a custom that survives in the flags of many Far Eastern countries such as India (a wheel), Japan (the sun), Mongolia and South Korea (Yin and Yang). Canada's maple leaf is one of the few symbols to appear on a western flag.
Flags spread to Europe via the Middle East, which still uses traditional Islamic colours of red, black, white or green and the crescent moon as symbols of its religious affiliation. Vexillologists (people who study flags) call these "flag families". Other families include the blue and white striped flags of several Central American states, the similar colour combinations of former French colonies in Africa and the Christian-derived crosses on the flags of ngland, Scotland and Scandinavian countries such as Denmark, Norway, Sweden and Finland.
The Union flag - an early 17th century attempt to merge the crosses of St George and St Andrew to which Ireland's red diagonal cross was later added - has always had a bit of an identity crisis, appropriated by groups as diverse as the Ulster Unionists, mods in the Sixties, and the Spice Girls in the Nineties. But when British Airways refused to fly the flag, replacing it on its tailfins with less jingoistic designs in 1997, public pressure forced the company to reinstate the red, white and blue.
A flag is a simple form of communication - acknowledged in the way we use the word to call attention to something (flag it up) or call a taxi (flag it down) - and single colours have universal meanings. The white flag signals a truce or surrender, the red flag is kept flying by socialists, the pirate's black flag has been adopted by anarchists, while in football a linesman waving a red or yellow flag indicates offside. But whatever their colour, flags can always be relied on to tell us one thing - the way the wind is blowing.