What would happen if Charles, William or whoever takes the throne next in the English monarchy made an acknowledgement that they didn’t believe in God and were in fact complete disbelievers: ergo, atheists.
Being the King or Queen of England also carries with it the title of head of the Anglican Church. But my question is, can one renounce the churchy bit, whilst still remaining monarch in a political sense?
The Act of Settlement requires that the monarch “joyn in Communion with the Church of England as by Law established.”
But I’m not sure if that’s actually incompatible with atheism. Does the Church of England have the power to kick someone out for that (or anything)? And I suppose you could make the argument that “joining” and “remaining” are different things.
I’d guess that the situation in the UK is the same as in Sweden: the monarch with family are the only people in the country that are required to belong to a certain church, which they cannot leave as they would then lose the right to succession to the throne.
Realistically, the answer is “Whatever Parliament decides.” If a monarch actually proclaimed both atheism and an unwillingness to lead the Church of England, Parliament could amend the Act of Settlement to sever the monarchy and the Church. The Prime Minister would then advise the monarch to grant royal assent, and he/she would - as properly housebroken constitutional monarchs always do. Or Parliament could insist upon following the letter of the law, and recognize whoever was next in the line of succession as the monarch.
Pope Paul III did revoke the title after Henry’s little spat. But since he no longer felt the need to pay attention to the Pope, Henry had Parliament give him their own Defender of the Faith title to replace it.