Unless our Brad is descended from Mary Queen of Scots he can never be King of Britain, even supposing the Black Death comes back. England possibly? but Scotland nae chance!!
Skoosh.
The English ran out of kings when their Henry VIII died and Queen Elizabeth ascended the throne. When she died they had to borrow a king from Scotland! So all the supposed English monarchs since then are descended from Mary Queen of Scots.
James VI and I had a Danish wife. His son Charles I had a French wife. His son James VII and II had an English wife but their line fizzled out. George I had a German wife. So did his son George II, and his grandson Frederick. Frederick's son George III had a German wife, as did his sons George IV, William IV, and Edward, whose daughter Queen Victoria married a German. Her son Edward VII married a Danish wife. His son's wife was American. George V's wife was German/Russian. Not until George VI did a monarch of the United Kingdom marry a British wife - and Lady Elizabeth Bowes-Lyon came of a Scottish family. HRH the Duke of Edinburgh is Greek/German. When/if the current Prince of Wales succeeds his mother, he will be the first British monarch since Henry VIII to have married an English wife and passed her genes on to future generations.
Puts Brexit in a different light, really.