Should hrh the Duchess of Cambridge hold her future baby hostage?

Absolutely. That's precisely what she should do, and what I would advise anyone to do in her position.

No. I wonder if you would abort your baby if you couldn't get your way over something.

What is the "crown matrimonial"?

I don't think she would need to, only because the Royal family knows that they are blessed to have the Duchess of Cambridge to be part of the family.

What an absurd prospect.

The wife of a king is a Queen Consort. This is the title the wife automatically receives under succession LAW of the UK.

Under current succession law, to be monarch, one must be a direct, legitimate descendant of the Electress Sophia of Hanover, a Stuart royal house member. Catherine is not an heir of Sophia, but her husband, William is. Under protocols, wives assume titles and styles of their husbands. There is no crown matrimonial for the non-heir, Catherine. Crown matrimonial was a Middle Ages concept where the husband reigned for his queen regnant wife,(women were not considered competent to reign), becoming king. This is no longer the Middle Ages; women have reigned without help of their husbands, and Catherine is not heir to the throne.

Kings' wives don't ever get the 'crown matrimonial'; they just get, routinely and inevitably, to become queens consort. Sometimes they have a formal coronation, sometimes not; but in either case, if they are legal wives they are legally queens. (Even if they haven't been on speaking terms, let alone living-together terms, with their husbands for years, as in the case of Caroline of Brunswick.) So there is no legal possibility, let alone any suggestion, that the Duchess worn become Queen if she is still married to William when he succeeds, so what you are maundering on about is a mystery.

The Crown Matrimonial is something else altogether: in the Middle Ages, when women were not considered competent to rule, that used to be granted to men who married queens regnant. Then whoever married the Queen would routinely become King and would actually call the shots. During the 16th and 17th centuries it became less routine: Philip of Spain got the Crown Matrimonial and became King of England when he married Queen Mary Tudor in 1554, but none of Mary Stuart's husbands did. The last man to get the crown matrimonial in Europe, as far as I know, was William of Orange in 1689.

Oh go away.

What are you talking about? She's supposed to get it. Charles will die before his mother.

I think she would do well to look at what happened to her mother in law to see what happens to people who try to hold the royal family to ransom.