I, [name], [swear by Almighty God] [do solemnly, sincerely and truly affirm and declare] that, on becoming a British citizen, I will be faithful and bear true allegiance to Her Majesty Queen Elizabeth II, her heirs, and successors, according to people.
I would not swear to that
I don’t mind as swearing allegiance to the Queen or future King but not their brothers/sisters etc, ONLY to the Queen and future Kings. It is the least I can do to show my respect to a nation that welcome me and to demonstrate that I mean no harm.
Actually, no matter which Kingdom I go to I shall bow to the King/Queen of that nation, if they have one, even if it is the Kingdom of my enemy as a sign of respect.
Royalist or not … it is the Head of the country that I showed my respect to and to the nation s/he governs. If there is no King/Queen then it would be the President or the head of state or in a remote village it would be the headman/woman. Even if the King/Queen no longer posses the power s/he once had, I will still pay my respect.