* The sixth brother, the Duke of Sussex, had ruled himself out of the race by marrying Lady Augusta Murray in contravention of the Royal Marriages Act (1772), which ordained that no descendant of George II could marry without the consent of the reigning monarch.

* Under the law of succession as it stood until 2013, a female heir to the throne could never be heir apparent, as the birth of a son to the monarch would defeat her claim, and he would become heir apparent. William IV was still hopeful of producing an heir, but none of Queen Adelaide’s babies lived.