Evidence of the Bible's Validity

[Mr Greene]

That's why I said 'head of state', which the queen is under the the standard parliamentary system. And yes I understand that she has very limited powers and for all intents and purposes is a figurehead.

Why is Charles not in line for the throne?

Because he married a divorced woman. Iirc that makes ineligible to be the head of the Anglican church, and if he can't head of the church he can't be king. That's why they make a fuss of William even though most of the royal family manages to stay out of the public eye.

No;
Whomsoever holds the favour of Westminster shall be Monarch.
As it stands that is Charles, the status of Camilla has no effect on that.
Whether or not that continues to be so is down to how much he interferes in party politics. If he were to follow Edward VII's example then the politicians might seek to have him abdicate though no politician of the current generation seems to have the proverbials of Churchill.