How the Flag is Made up

 

How to Draw the Union Jack

 

  

   The Union Jack, with construction lines
The flag of the United Kingdom, the Union Jack, is a superposition of the flags of Saint George (for England), Saint Andrew (for Scotland) and Saint Patrick (for Ireland). This superposition is quite intricate, and often drawn incorrectly.

The flag is twice as wide as it is high. The cross of St George is red, and has width equal to one fifth the flag's height, and a white border of width one fifteenth the height.

The cross of St Andrew is interchanged with that of St Patrick. Start by drawing the diagonals of the whole flag, and then the lines parallel to these that are at a distance of one tenth and one fifteenth the height of the flag. (For clarity the diagram also shows the lines that are apart from the diagonals by only one-thirtieth the height.) On the flag-pole side fill red the diagonally-orientated area of width one fifteenth the height that lies below the diagonals, and on the non-flag-pole side, the diagonally-orientated area of width one fifteenth the height that lies above the diagonals. Finally, fill blue everywhere that is both more than one-tenth the height away from the diagonals, and more than one fifteenth the height away from the red of the cross of St George.

The blue should be Pantone 280, approximated here with an RGB setting of 0:0:102, and the red should be Pantone 186, approximated here with 204:0:0. (Thanks for drawing my attention to the colours goes to Graham Bartram, who maintains a site with excellent images of UK flags at www.flags.net/UNKG.htm.)
Part of an incorrectly-drawn Union Jack The Union Jack is often drawn incorrectly. The ellipse on the left shows a typical error, in which (wrongly) the cross of St Patrick abuts at a right-angle to the white edge of the cross of St George.

In the 2:1 version of the flag (which is what you want unless you really know otherwise) the four red parts of the cross of St Patrick should always be quadrilaterals. Two of the quadrilaterals have two sides parallel and two perpendicular; the other two have both pairs of non-adjacent sides parallel. The four red parts of the cross of St Patrick should not be pentagons or hexagons, although are often drawn that way.

Areas. If the flag is drawn 60 by 30 as in the top diagram, then the various parts have areas as follows, where s is the positive square root of five. The red of the cross of St George is of area 504 square units. The blue of the cross of St Andrew is in eight pieces, four larger and four smaller. The larger pieces each have area (335-75s)/2; the smaller each 445/4-30s; giving a total blue area of 1115-270s, which, at about 511.261646 square units, is slightly more than 1.44% larger than the cross of St George. The red of St Patrick is in four pieces, two larger and two smaller, these respectively each having area 20s and 20s-5; for a total of 80s-10, about 168.8854382 square units. Thus the flag is red : white : blue in the proportions 494+80s : 191+190s : 1115-270s, or about 37.38% : 34.21% : 28.4%.

The author is occasionally asked which of "Union Jack" and "Union Flag" is the correct name. The Flag Institute answers as follows:

It is often stated that the Union Flag should only be described as the Union Jack when flown in the bows of a warship, but this is a relatively recent idea. From early in its life the Admiralty itself frequently referred to the flag as the Union Jack, whatever its use, and in 1902 an Admiralty Circular announced that Their Lordships had decided that either name could be used officially. Such use was given Parliamentary approval in 1908 when it was stated that "the Union Jack should be regarded as the National flag".

However, the Royal Navy disagrees:

The national flag of the United Kingdom is worn as a Jack at the bow by all HM ships in commission when alongside or when 'dressed overall'. This is the only occasion when it is correctly called the Union Jack, although it is generally known by this name through common usage. It is also flown during Courts Martial and is the Distinguishing Flag of an Admiral of the Fleet.