As a citizen of the US I think of the UK as a sub-part of Europe. Not the same place since France & Greece are also part of Europe, but not part of Britain. There are still some parts of Europe that are not EU, so those aren't exactly the same either. Citizenship is a bit different do you vote in EU elections, pay EU taxes, or benefit from EU services? Does the EU have a class of people it considers citizens vs. residents who are not citizens?

I happen to reside in New York State right now, so I am also a citizen of New York and the town I live in. I was not born here and my state and town citizenship has easily changed as I have moved. I'm also part of the area covered by NAFTA. I live in North America, but there is no citizenship here in the sense of voting, paying taxes, collecting Social Security, etc, that I have in local, state, and national issues. Actually, we can pay taxes & collect Social Security without being a citizen, but it's our governmental agencies that administer them.