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.