Initially, the Union Flag was exclusively for royal use. It was flown on all the King’s forts and castles and nowhere else. Nowadays it is flown by many people all over the UK. The flying of the Union Flag on public buildings is decided by the Department for Culture, Media and Sport at the Queen’s command. Any civilian on land can use the flag, but at sea, non-naval/military use of the flag is prohibited; in the 17th century the flag was used deceptively by merchant ships to pose as naval ships and avoid paying harbour duties, so Charles I ordered that only Royal ships could use the flag. It is still a criminal offence under the Merchant Shipping Act 1993 to display it on a British civilian ship.
Nations and colonies that have used the Union Flag at some point include Aden (Yemen), America, Borneo, Cyprus, Kenya (East Africa), India, Jamaica, Lagos, Gambia, Ghana (Gold Coast), Malta, Mauritius, Nigeria, Palestine, Penang, Sierra Leone, Singapore, Trinidad and more. The most recent decommissioning of the Union Flag was when Hong Kong was returned to China in 1997. The Basque country’s flag, the Ikurrina, is loosely based on the Union Flag. US Navy vessels also fly a flag they call the ‘Union Jack’: the ‘stars’ section of the Stars and , without the stripes.
The study of flags is ‘vexillology’.
There is hopeful symbolism in the fact that flags do not wave in a vacuum.
The use of visual signals to communicate over distance at sea is probably as old as seafaring itself, but it wasn’t until 1857 that the International Code of Signals was established by the British Board of Trade. It consisted of 18 flags, which in differing combinations could be used to send 70,000 distinct signals.
The International Maritime Organisation now manages a universally agreed system of signals by which coded messages can be sent by semaphore, radio, Morse, blinker lights or international maritime signal flags. Each flag represents a letter (so that messages can be spelt out) but also has a more specific meaning. ‘F’ means ‘I am disabled, please communicate with me’, ‘J’ is ‘I am on fire’ and ‘Z’ is ‘I require a tug’.
Semaphore (Greek for ‘sign-carrier’) is a spelling system that uses two flags. It was first proposed by Robert Hooke (1635-1703), the man who discovered the laws of elasticity, claimed to have discovered gravitation before Newton, and with Christopher Wren, rebuilt London after the Great Fire. Hooke’s semaphore was not taken up for over 100 years until Frenchman Claude Chappe (1763-1805) came up with a practical system using rods mounted on towers.
At the 1936 Olympics, Liechtenstein realised its flag was exactly the same as Haiti's, so added a crown to the top left corner.
The iconic CND peace symbol is based on the semaphore code for ‘N’ and ‘D’, set within a circle symbolising Earth.
The Union Flag wasn’t officially designated as the national flag until 1908. It features the crosses of St George, St Andrew and St Patrick. The latter was added to the previous Union Flag of St George and St Andrew after the Act of Union of Ireland with England and Wales and Scotland on 1 January 1801. Other early suggestions included St George’s Cross with St Andrew’s flag by its side. The Scots liked a version with the Scottish cross on top. Some Welsh say the Red Dragon or Flag of St David ought to be on the flag, and it is of course an historical curiosity that the flag includes Ireland (which is not part of the UK) but excludes Wales (which is).
To fly the flag the correct way up, the broad portion of the white cross of St Andrew should be above the red band of St Patrick (and the thin white portion below) in the upper hoist canton (the corner at the top nearest to the flag-pole), giving the Scottish symbol precedence over the Irish symbol. This is expressed by the phrases ‘wide white top’ and ‘broad side up’. Traditionally, flying a flag upside down is understood as a distress signal. In the case of the Union Flag, the difference is so subtle as to be easily missed by many (of course there are many flags which are actually identical upside-down, such as the French tricolour).
From 1814 to 1830, the French flag was plain white.
The Blue Peter flag can mean the letter ‘P’, ‘Get on board, we're about to leave!’ or ‘Your lights are too dim.’
American Boy Scouts' traditional way to dispose of a US flag is to ‘destroy it in a dignified way, preferably by burning’
Put out more flags in order to increase splendour.