Shock, horror, this potential war doesn't involve religion
Thing with this is, it's more complex than it looks. Let's imagine Britain is completely taken over by the EU (Not as insane as it might sound, it might go that way). Britain exists as a separate statelet, but the EU calls the shots.
Now imagine if the EU government decides to award Hampshire to France as a gift. Remember - on the face of it, this doesn't really matter that much, because we are all part of the same EU state, it just means local matters for Hampshire are now dealt with by Paris.
Along comes the breakup of the EU, the UK becomes independent, as does France - but France includes Hampshire. The UK pays rent to France for Portsmouth harbour. Most people in Hampshire are English.
A new government a few years down the line decides to play a nationalist line, and officially doesn't like English speakers. People in Hampshire start putting up Union flags and chanting "frog off".
Would we then be surprised if the UK government threatened to send in the tanks to protect those English speakers - basically the British left in Hampshire after the EU gave them away 50 years ago to France?
This is one we really need to keep the hell out of