Flag of the United Kingdom
The Union Flag joins three crosses on a blue field: the red cross of St George for England, the white diagonal cross of St Andrew for Scotland and the red diagonal cross of St Patrick for Ireland, added to the first two in 1801. No law defines it; it is the national flag by long custom, the Flag Institute says.
Easily confused with
- Flag of ScotlandScotland’s flag, the Saltire, is a white diagonal cross on a blue field: the cross of St Andrew, Scotland’s patron saint, who by Christian tradition was crucified on a cross of that shape. Scottish tradition also tells of a white saltire seen against a blue sky before a battle at Athelstaneford, which the Scottish Flag Trust calls a legend.
- Flag of EnglandEngland’s flag is St George’s cross: a red cross on a white field, running to all four edges. It is the cross of St George, England’s patron saint, and it is also the upright red cross in the Union Flag of the United Kingdom.
- Flag of HawaiiHawaii’s flag has eight horizontal stripes of white, red and blue with the British Union Jack in the upper corner by the pole. Store norske leksikon says the stripes stand for the main islands and that the British flag was kept because Britain was the leading power and a safeguard against Russian attempts on the islands.
How to read it
England’s and Scotland’s crosses were first joined in 1606, when King James VI and I ordered ships of both kingdoms to fly St George’s cross and St Andrew’s cross together; St Patrick’s cross was added from 1 January 1801, when the Act of Union created the United Kingdom of Great Britain and Ireland. No act of Parliament sets out the design. The UK government calls it the national flag of the United Kingdom, the Crown Dependencies and the Overseas Territories, and the Flag Institute, a UK charity for the study of flags, says it is the national flag “by long-established custom and practice rather than by statute”. The Institute’s recommended specification is 30 units high by 50 long (3:5) on land, with ensigns at sea customarily 1:2, in royal blue (Pantone 280 C) and red (Pantone 186 C). Union Flag and Union Jack are both correct names: an Admiralty circular declared either name official in 1902.
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Which way up the Union Flag goes
It has a right way up. The two diagonal crosses are counterchanged, so the white of St Andrew’s cross is broader on one side of the red of St Patrick’s cross than on the other. In the half next to the pole, the broad white stripe goes above the red; with the red on top, the flag is upside down. The Flag Institute explains the rule as Scotland’s cross taking precedence over Ireland’s, and calls flying it upside down “most improper”. In its specification each diagonal is 6 units wide: white 3, red 2, white 1.
The three crosses
St Andrew’s cross is a white saltire, heraldry’s word for a diagonal cross. Its blue was lighter in 1606 and darkened over time, so Scotland’s own flag still has a lighter blue (Pantone 300) than the Union Flag (Pantone 280). St George’s red cross runs edge to edge through the middle, 6 units wide, with a white border 2 units wide.
St Patrick’s red saltire was designed by the College of Arms for the 1801 flag. The Flag Institute says it came from the insignia of the Order of St Patrick, founded in 1783, and from the arms of the Fitzgerald family; Royal Museums Greenwich also traces it to the Fitzgerald arms. The Institute adds that St Patrick was not a martyr and so not, strictly, entitled to a cross.
Days it must fly
UK government buildings must fly the Union Flag on designated days by command of the King, among them each patron saint’s day in its own nation, Commonwealth Day, the King’s official birthday and Remembrance Day, and are encouraged to fly it every day. Where two flags fly, the Union Flag takes the superior position: the highest pole, or the centre one of an odd number of poles of the same height.
Where this symbol came from
oldsymbols.comOrdinariesThe crosses of St Andrew and St Patrick are saltires, one of heraldry’s ordinaries. oldsymbols.comGrand Union flagThe first American flag of thirteen red and white stripes, with the British Union Flag in the canton where the stars later went. The Continental Navy flew it from December 1775, and it remained the unofficial flag until Congress adopted the Stars and Stripes on 14 June 1777.Read next
- Next in European flagsFlag of IrelandGreen, white and orange in equal vertical bands, green next to the pole. The Irish government says the flag stands for the inclusion of, and hoped-for unity between, the people of different traditions on the island; Thomas Francis Meagher, who flew it in 1848, said the white in the centre signified “a lasting truce between Orange and Green”.
- The same shape in African flagsFlag of BurundiA white diagonal cross divides the flag into red triangles at top and bottom and green ones at the sides, with a white disc in the centre holding three red six-pointed stars. The Presidency of Burundi says the red recalls the sacrifices made to defend the nation and win independence, the green hope and prosperity, the white peace and unity, and that the three stars traditionally stand for the national motto, “Unity, Work, Progress”.
More european flags
The same shape elsewhere
Browse symbols drawn with crosses or squares and rectangles.
Sources
- Union Flag Specification, Flag Institute, Union Flag Specification, The Flag Institute, Specification, points 1–8 and diagram notes
- UK flag protocol, Flag Institute, UK flag protocol, The Flag Institute, Introduction; flying the flag
- History of the Union Flag, Flag Institute, History of the Union Flag (Graham Bartram), The Flag Institute, 1606 proclamation; Act of Union, 1801
- Union Jack or Union Flag?, Flag Institute, Union Jack or Union Flag? (Cdr Bruce Nicolls), The Flag Institute, A brief history
- Designated days for flying the Union Flag on UK government buildings, Department for Culture, Media and Sport, Designated days for Union Flag flying (guidance), GOV.UK (Department for Culture, Media and Sport), Introduction; Flying the Union Flag; Designated days 2026
- Union Flag (before 1801), Royal Museums Greenwich, collections object: Union Flag (before 1801), Royal Museums Greenwich, Object description
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 13, 2026. How we research
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