OK, I imagine the British who live in Europe want to stay where they live, despite the Brexit vote, so I imagined this song being sung by the British government to the government of the European Union, as a plea to not throw all the British out once they aren't European citizens any more. Also, it's about how European they are in their host countries... To the tune of, obviously, Let My People Go (the Peter, Paul and Mary version):

LET MY PEOPLE STAY

Go to the halls of Brussels
Over the Channel, everywhere
Go ask the halls of Brussels
To let my people stay

Who's that yonder speaking French (let my people stay)
Eating croissants on a Paris park bench (let my people stay)
Who's that yonder speaking French, eating croissants on a Paris park bench, go to the halls of Brussels...

Who's that yonder speaking Dutch?
Amsterdam folks keep their stash in a hutch...

(then you can plug in other places)

LAST verse:

Who's that speaking Norwegian?
Oh, never mind, that one's Glaswegian...

Get it? In case Scotland leaves the UK...

Annyway, add some verses, y'all!