The United Kingdom’s flag combines the crosses of Saint George, Saint Andrew, and Saint Patrick. It is commonly called the Union Jack or Union Flag.
The design places England’s red Cross of Saint George over Scotland’s white saltire of Saint Andrew, set against a blue field. The current version adds Ireland’s red Saltire of Saint Patrick, edged in white, after the 1801 Act of Union joined Great Britain and Ireland in the United Kingdom.
Earlier versions existed before the present flag: the first Union Flag dates from 1606, and a redesigned version represented the union of England and Scotland in 1707. The modern arrangement dates from 1 January 1801. Its offset red and white diagonals are deliberate, ensuring that the flag is not symmetrical and has a correct orientation.
England, Scotland, and Wales are not interchangeable answers. England has the red Saint George’s Cross, Scotland has the white Saint Andrew’s Cross, and Wales is represented in the Union Flag only indirectly because Wales was already legally incorporated into England when the union design developed.