Union Flag, also known as the Union Jack

The Union Flag or Union Jack is the flag most commonly associated with the United Kingdom of Great Britain and Northern Ireland and was also used throughout the former British Empire. It retains an official or semi-official status in many Commonwealth Realms including being an official flag of Canada. The current design (which is used as the national Flag of the United Kingdom) dates from the Union of Ireland and Great Britain in 1801.

Flag of England, also known as the St George's Cross

The Flag of England is the cross of Saint George. The legend of Saint George slaying the dragon dates from the 12th century and Saint George became the patron saint of England in the 13th century. The flag consists of a red cross on a white field with the cross having a width of 1/5 of the height of the flag. The flag proportion is 5:3.

When the Kingdom of England and the Kingdom of Scotland were united in a personal union under James VI/I, the Cross of Saint George was combined with the Cross of St. Andrew (representing Scotland) to form the original Union Flag (or "Union Jack"). This flag later became the national flag of the Kingdom of Great Britain, and was combined with Flag of St. Patrick (representing Ireland) in 1801, producing the current Union Flag of the United Kingdom. The proportions of the Union Flag are 2:1.

Flag of Scotland, also known as the St Andrew's
Cross, and the Saltire

The Flag of Scotland features a white saltire, a Crux decussata (X-shaped cross) representing the cross of the Christian martyr Saint Andrew (patron saint of Scotland) on a blue field. It is often known as The Saltire or the Saint Andrew's Cross. In heraldic language, it may be blazoned Azure, a saltire argent.

The Scottish flag is one of the oldest flags in the world, dating back to the 9th century. According to legend, King Oengus of Dalriada (or King Angus) led the Picts and Scots in battle against the Angles under Athelstan in 832. King Angus and his men were surrounded and he prayed for deliverance. During the night Saint Andrew, who was martyred on a diagonal cross, appeared to Angus and assured him of victory. On the morrow a white saltire against the background of a blue sky appeared to both sides. The Picts and Scots were heartened by this but the Angles lost confidence and were defeated. The Saltire has been the Scottish flag ever since. The earliest record of its use in its current form is in 1277, in the reign of Edward I.

At various times colours as light as sky blue or as dark as dark navy have been used (a selection apparently motivated by which colour of blue dye was cheapest at the time), although recent versions have largely converged on the official recommendation of Pantone 300. In 2003 a committee of the Scottish Parliament proposed that the Scottish Executive (Scottish Government) adopt this colour as a standard. It is worth noting that this blue is of a lighter shade than the Pantone 280 of the Union Flag). The flag proportion is not fixed but is generally taken as 5:3 or 3:2, the former being preferred. The cross should have a width of 1/5 of the height of the flag.

The Scottish saltire and field is one of the components of the Union Flag. A reversed version (blue saltire on a white field) is to be found in the naval jack of Russia (see Russian Navy) used before and after the Soviet Union (Saint Andrew is also a patron saint of Russia). Additionally, the blue saltire on white design is featured on the Coat of Arms of Nova Scotia, Canada and its flag, but the blue used for Nova Scotia is generally a light blue. The Spanish island of Tenerife also uses the saltire as its flag.

Flag of Northern Ireland, unofficial

Northern Ireland has not had its own unique official flag since 1972, when its government was prorogued. Due to the division of the population along religious and political lines, a wide variety of flags can be seen flying from lamposts and private houses across Northern Ireland.

Flag of Wales, also known as the Red Dragon

The national flag of Wales is The Red Dragon (Welsh: Y Ddraig Goch). It consists of a red dragon, passant, on a green and white field. The exact representation of the dragon is not standardised and many different interpretations exist.

The flag was granted official status in 1959, and is based on an old royal badge used by English and British monarchs since the Tudor dynasty: on a mount vert a dragon gules. The red dragon itself has been associated with Wales for centuries; on this basis, the flag is sometimes claimed to be the oldest national flag still in use. The origin of the adoption of the dragon symbol is now lost in history and myth. A plausible theory is that the Romans brought the emblem to what is now Wales during their occupation of Britain, but it could be even older. The green and white stripes of the flag were additions by the House of Tudor, the Welsh dynasty that held the English throne from 1485 to 1603 (green and white are also the colours of the leek, another national emblem of Wales).

The oldest recorded use of the dragon to symbolise Wales is from the Historia Brittonum, written around 820, but it is popularly supposed to have been the battle standard of Arthur and other ancient Celtic leaders. It is particularly associated in Welsh poetry with Cadwaladr king of Gwynedd from c.655 to 682. Many legends are associated with the Welsh dragon. The most famous is the prophecy of Myrddin (or Merlin) of a long fight between a red dragon and a white dragon. According to the prophecy, the white dragon would at first dominate but eventually the red dragon would win. This is an allegory of the historical struggle between the Welsh and the English.

Wales and Bhutan are the only countries to have a dragon on their flag.