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.
Union Jack is permitted on land, but use of the unmodified flag at sea is restricted to military vessels. Unauthorised use of the flag in the 17th century to avoid paying harbour duties – a privilege restricted to naval ships – caused James's successor, Charles I, to order that use of the flag on naval vessels be restricted to His Majesty's ships "upon pain of Our high displeasure." It remains a criminal offence under the Merchant Shipping Act 1995 to display the Union Flag (other than the "pilot jack" – see below) from a British ship. Naval ships will fly the white