Union Flag specification

The Union Flag is the world's only national flag with no basis in law, so this specification recommended by the Flag Institute is the accepted standard. For the rules on flying the Union Flag, see UK flag protocol.

The specification

1. The Union Flag comprises three crosses on a royal blue background: a red St George’s cross, a white St Andrew’s saltire and a red St Patrick’s saltire.
2. The proportions of the flag are 30 units wide by 50 units long.
3. Each diagonal is in total 6 units wide, comprising white (3 units), red (2 units), white (1 unit):
   • the broader white diagonal is uppermost at the hoist (i.e. nearest the flagpole);
   • the narrower white diagonal is uppermost at the fly (i.e. furthest from the flagpole).
4. These two 6-unit-wide diagonals run from corner to corner:
   • the central line of each diagonal intersects opposite corners of the flag;
   • these two central lines intersect in the centre of the flag.
5. A 6-unit-wide red cross runs from edge to edge, centred on the flag.
6. This red cross has a 2-unit-wide white fimbriation (border).
7. The flag should fly with the broader white diagonal uppermost at the hoist (i.e. nearest the flagpole).
8. The recommended colours are: Pantone 280 C (royal blue); Pantone 186 C (red); no specification (white).

Construction diagram

• the normal proportions for use on land are 3:5
• the customary proportions of ensigns for use at sea are 1:2
• the specification for the 1:2 version replaces the length of 50 with 60
• the specification for the 1:2 version replaces the angle of 30.96° with 26.57°.

Union Flag Bill (2008)

The Flag Institute has tried without success to give the Union Flag a basis in law, most recently in the Union Flag Bill (2008). The bill was introduced under the Ten-Minute Rule but failed to progress beyond its first reading (Hansard 5 February 2008, Columns 792-94).