1 The St George’s Cross is the flag of England.
2 The Saltire is the flag of Scotland.
3 Put them together, and you get this. But under flag rules, two colours are not allowed to touch.
4 Colours are always separated by white borders.
5 This is the saltire of the Principality of Wales.
6 Adding it into the mix breaks the rules again: two colours are not allowed to touch.
7 So extra white space is added to separate the elements.
8 But Wales is a principality, not a country. So it mustn’t appear to dominate. That’s why the Welsh saltire is offset in this curious way, to give it less prominence.
The golden rule: the thick white stripe is always on the right, at the top corner nearest the flagpole. The following thick white stripes follow in clockwise fashion around the flag.
See also