Blue Ensign

The Blue Ensign is a flag, one of several British ensigns, used by certain organizations territories associated or formerly associated with the United kingdom, it is used either plain or defaced with a badge or other emblem.
The Acts of Union 1707 united England and Wales with Scotland in the Kingdom of Great Britain, in the result of producing a new Blue Ensign with the new Union Flag in the canton. With the Act of Union 1800, Ireland became a part of the new United Kingdom of Great Britain and Ireland, and St Patrick's Cross was incorporated into the Union Flag and, accordingly, into the cantons of all British ensigns from 1 January 1801.