It is not that United. Ireland is two countries (one in the EU, one in the UK) and its own language. Scotland has its own parliament, own language and many Scots want to leave the UK. Wales has its own assembly, its own language and some Welsh people want to leave the UK. Many people on the fringes of Britain (ie away from SE England) dislike the centralized government in Westminster.
In the Olympics we will all be one team (except the Republic Of Ireland). In football and rugby we are separate teams...
I'm Welsh, don't speak my own language (massively suppressed in Wales until the 1950s but is likely the oldest language among these islands, still widely spoken in the UK) with a British passport, who is anti-monarchy.
I don't underhand the UK, either....