Names	Union Jack, Union Flag, other names: The Britain; The British Flag; the Union; The Banner of the Union; the Great Union; the Flag of the Union; the Jack; The King's Jack; His Majesty’s Jack; Our Jack; the Jack Flag
Use	National flag
Proportion	3:5 (on land) 1:2 (at sea)
Adopted	1 January 1801; 223 years ago (1801-01-01) first design: 12 April 1606; 417 years ago (1606-04-12)
Design	A combination of the crosses of SS Andrew, George, and Patrick
Variant flag of the United Kingdom of Great Britain and Northern Ireland
Use	Civil ensign
Proportion	1:2
Design	A red flag with the Union Flag in the corner at the top of the flag pole. See Red Ensign.
Variant flag of the United Kingdom of Great Britain and Northern Ireland
Use	Civil air ensign
Proportion	1:2
Design	A blue flag with the Union Flag in the corner at the top of the flag pole and a black cross in the centre. See Civil Air Ensign.
Variant flag of the United Kingdom of Great Britain and Northern Ireland
Use	State ensign
Proportion	1:2
Design	A blue flag with the Union Flag in the corner at the top of the flag pole. See Blue Ensign.
Variant flag of the United Kingdom of Great Britain and Northern Ireland
Use	Naval ensign
Proportion	1:2
Design	A white flag with the Union Flag in the corner at the top of the flag pole and a red cross in the centre. See White Ensign.
Variant flag of the United Kingdom of Great Britain and Northern Ireland
Use	Air force ensign
Proportion	1:2
Design	A blue flag with the Union Flag in the corner at the top of the flag pole and the RAF roundel on the opposite side.

The flag of the United Kingdom is the Union Flag or Union Jack. The Union Flag is the national flag of the United Kingdom. It has had the same design since the Act of Union 1800. The flag is made from the flags of the kingdoms of England, Scotland, and Ireland.