So they are different countries?
How are they united?
Since I'm not going to pretend to be an expert in British history, I'll consult Wikipedia...
'The United Kingdom was created out of the existing historic kingdoms of England (including Wales), Ireland and Scotland. Between the 17th and 19th centuries a series of political events brought these constituent elements into a close political union. England, Ireland and Scotland were brought into a personal union by the Union of the Crowns in 1603, when James VI, King of Scots inherited the Kingdoms of England and Ireland and moved his court from Edinburgh to London, although all three kingdoms retained their separate political institutions.
On 1 May 1707, the Kingdom of Great Britain was created by the political union of the Kingdom of England (which included Wales) and the Kingdom of Scotland. This event was the result of the Treaty of Union that was agreed on 22 July 1706, and then ratified by both the Parliament of England and Parliament of Scotland each passing an Act of Union in 1707.
Almost a century later, the Kingdom of Ireland, merged with the Kingdom of Great Britain to form the United Kingdom of Great Britain and Ireland with the passing of the Act of Union 1800. Disputes within Ireland over the terms of Irish Home Rule led eventually to the partition of the island in 1921, with Dominion status for the Irish Free State in 1922 and Northern Ireland remaining part of the UK. As a result, in 1927, the formal title of the UK was changed to its current form, the United Kingdom of Great Britain and Northern Ireland.'
