Thank you all very much for your help. Besides, I would like to give my answers to related questions that incidentally came up:
Liechtenstein is a Principality, and so is Monaco. The only remaining sovereign nation that officially has a Duke as Head of State in Europe is the Grand Duchy of Luxemburg.
And Pjen’s questions:
- Yes. The law concerning the rules of succession dates back to 1707, IIRC.
- Formally no, because it has given an oath of loyalty towards Elizabeth II. and her rightful heirs and successors (the same oath is given by the deputies of Canda, Australia and New Zealand parliaments). Practically, the monarch does not have any influence on the governement of the country.
- Practically no. Formally, the monarch has to give consent to every act of Parliament, but it hasn’t been denied since 1707. Nowadays, after Parliament passes a bill, there is automatically announced that the Royal Assent has been given, without asking the sovereign.
- I don’t think so.
- No Catholic person can become King/Queen (because the monarch is head of the Church of England, and Britons used to be afraid that Catholics could regain power over their realm a few centuries ago), and noone married to a Catholic.
- Yes, of course.
- Yes, since the 1980s. Elizabeth has voluntarily agreed to pay taxes. See http://www.royal.gov.uk
- The really valuable things -Buckingham Palace, Crown Jewels etc.- are property of the State, but the monarch has the exclusive right to use it. Other castles (Sandringham, I suppose) are the monarch’s private property, but the public would hardly agree if the monarch decided to sell it, so Lizzie doesn’t have real power over it.
- There’ll be a new one, according to teh usual accession rules. See Edward and Wallis in 1936, which got Elizabeth’s father on the throne.