[Bret L]

It's very simple. When the Czech and Slovak Republics were formed out
of what had been Czechoslovakia, you were either a national of one or
the other Republic.Not both. When the US became independent of
Britain, you were no longer a British subject if you were an American.
How hard is this?

Or are all Americans still also British subjects entitled to a UK
Passport? If you are saying Puerto Ricans are all Americans forever,
you have to be saying all Americans are Britons forever. Or is that
not true? And if not why not?