Charles III

Charles III was the King of the United Kingdom who succeeded Elizabeth II. Charles reigned with his Queen, Camilla, and was succeeded by William V. When the Tenth Doctor found that Edward VII had disappeared along with Balmoral Castle in 1902, he warned that the future of the royal family, along with the rest of history, was threatened. Saying that, along with the rest of his successors, there would be no Charles III. (QR: Revenge of the Judoon)

Behind the scenes

 * Charles is likely the unnamed King mentioned in DW: Battlefield, which is probably set in a period during the 1990s when Elizabeth was temporarily off the throne. It has also been suggested Battlefield may have taken place in a alternate timeline.