Union Jack Union Jack 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.
Flag of Australia Union Flag in the UK, when the House of Representatives proclaimed that the Blue Ensign "should be flown upon all forts, vessels, saluting places and public buildings of the Commonwealth upon all occasions when flags are used". The government agreed to fly the Blue Ensign on special flag days, but not if it meant additional expense, which undermined the motion. The Blue Ensign could only be flown on a state government building if a state flag was not available. On 2 June 1904 a resolution was passed by parliament to replace the Union Jack with the "Australian Flag" on forts.