The UK news today is dominated by a meeting between the UK prime minister and the Scottish first minister about the possibility of Scotland declaring independence. There is much talk of the 1707 Act of Union, and of James VI/I, but in fact the first union between the English and the Scots was negotiated right here in Cumbria on 12thJuly, 927CE.
At this point in history, it wasn’t about England, Scotland, Ireland and Wales. There was Mercia and Wessex; Northumbria and Dublin; Strathclyde and Cumbria; the Scots; various Welsh provinces and a whole lot more. There was no concept of a combined Britain, never mind UK.