Adopted in 1606. The flag of the United Kingdom has a blue field with the red cross of Saint George (patron saint of England) edged in white superimposed on the diagonal red cross of Saint Patrick (patron saint of Ireland), which is superimposed on the diagonal white cross of Saint Andrew (patron saint of Scotland). Properly known as the Union Flag, but commonly called the Union Jack; the design and colors (especially the Blue Ensign) are the basis for a number of other flags including Commonwealth countries and their constituent states or provinces, and British overseas territories. (ref: CIA World Factbook)