<Tr> <Th> Adopted </Th> <Td> 1801 </Td> </Tr> <Tr> <Th> Design </Th> <Td> Cross of Saint Andrew counterchanged with the Cross of Saint Patrick, over all the Cross of Saint George . </Td> </Tr> <P> The Union Jack, or Union Flag, is the national flag of the United Kingdom . The flag also has an official or semi-official status in some other Commonwealth realms: for example, it is a ceremonial flag in Canada by parliamentary resolution, and known there as the Royal Union Flag . Further, it is used as an official flag in some of the smaller British overseas territories . The Union Flag also appears in the canton (upper left - hand quarter) of the flags of several nations and territories that are former British possessions or dominions, as well as the state flag of Hawaii . </P> <P> The claim that the term Union Jack properly refers only to naval usage has been disputed, following historical investigations by the Flag Institute in 2013 . </P>

Which country's flag is known as the union jack