The flag of the United Kingdom of Great Britain and Northern Ireland, commonly known as the Union Jack or Union Flag, is the national flag of the United Kingdom.

The current design of the Union Jack dates from the union of Ireland and Great Britain in 1801. It consists of the red cross of Saint George (patron saint of England), edged in white, superimposed on the Cross of St Patrick (patron saint of Ireland), which are superimposed on the Saltire of Saint Andrew (patron saint of Scotland). Wales, however, is not represented in the Union Flag by Wales's patron saint, Saint David, as at the time the flag was designed Wales was part of the Kingdom of England.