United Kingdom (Naval) Flag: Meaning and History

The Union Jack in its current form dates back to the early 19th century and represents each of the countries of the kingdom.
History of the flag
The Red Ensign is the official civil flag of the United Kingdom and is used by British merchant and civil vessels.
This flag serves to identify British ships in international waters.
What do the elements of the flag mean?

The British canton pays tribute to the United Kingdom and the Commonwealth.
Easily identifiable on the high seas, this color symbolizes courage.
