United Kingdom History
"Great Britain" ("GB", "Britain") refers just to the biggest island, that is, Scotland, England, and Wales together. Great Britain became part of the United Kingdom when the Irish and British parliaments merged in 1801 to form the "United Kingdom of Great Britain and Ireland". This was changed to "... and Northern Ireland" when all but six Irish counties left the Union in 1921 after a treaty. "Britain" is often used as shorthand for the whole of the United Kingdom, even though this is strictly incorrect.
Don't describe the country as "England". It is incorrect and may offend people from Wales, Scotland and Northern Ireland who will not identify themselves as being from "England".
The flag of the United Kingdom is popularly known as the Union Jack or Union Flag . It comprises the flags of St. George (of England), St. Andrew (of Scotland, also known as the Saltire ) and the St. Patrick's Cross (of Ireland) superimposed on each other. Within England, Northern Ireland, Scotland and Wales, the flags of each nation are commonly used. The St. Patrick's Cross flag is often seen on St. Patrick's Day in Northern Ireland. Since the Republic of Ireland split from the UK though, St. Patrick's Saltire is not used for Northern Ireland, as it represented the whole of the island of Ireland. A flag (known as the "Ulster Banner") was designed for Northern Ireland in the 1920s, which was based on the flag of Ulster (similar in appearance to the St. George's Cross flag of England) and includes a Red Hand of Ulster and a crown. Although the flag's official status ended with the dissolving of the province's devolved government in the early 1970s, it can still be seen in Northern Ireland, particularly among the Protestant community and on sporting occasions. As Wales was politically integrated into the English kingdom hundreds of years ago, its flag was not incorporated into the Union Jack. The flag features a Red Dragon on a green field.
The Isle of Man and the Channel Islands are not strictly part of the UK, but rather are 'Crown Dependencies'. This means that they have their own democratic governments, laws and courts and are not part of the EU; but they are not entirely sovereign either, falling under the British Crown which chooses to have its UK Government manage some of the islands' affairs. The people are British Citizens, but unless they have direct ties with the UK, through a parent, or have lived there for at least 5 years, they are not able to take up work or residence elsewhere in the European Union .