With the royal wedding looming on Friday, expect to read plenty about a  non-existent Princess Camilla, married to a non-existent Prince Charles, writes Jim Duffy

Princess Diana never existed. Nor does Prince Charles. Queen Victoria was really Mrs Victoria Wettin. And Camilla will soon be Princess of Wales and will one day be queen. Are you puzzled? Surprised? Welcome to the confusing world of British royal titles and names.

Let's start with Charles. No, not Prince Charles. He hasn't officially had that name since February 1952 when he changed from being Prince Charles of Edinburgh to being Duke of Cornwall. When someone becomes a royal peer they cease to be called Prince or Princess, except curiously in Scotland, where Charles is officially The Prince Charles, Duke of Rothesay.

And sorry to disappoint Sinn Féin but he is not Charles Windsor either. Royalty have ordinary names and royal house names. Prince Albert's royal house name may have been Saxe-Coburg-Gotha but as his surname was Wettin, Queen Victoria's personal name was Victoria Wettin. (She so hated the name she banned its use.)

In 1917 both the royal house and personal names were replaced by one single name, Windsor. But to keep the Duke of Edinburgh happy (he didn't like being the only married British father whose children could not inherit his surname) Queen Elizabeth II decided that all their descendants would have a separate surname combining both parents' surnames: Mountbatten-Windsor. So Charles's wedding banns in 1981 called him Charles Mountbatten-Windsor (and Anne's called her Anne Mountbatten-Windsor).

Charles had escaped lightly. He could have been Charles Gluckburg-Wettin. Or if the Royal House and surnames were the same and had not been anglicised he could have been Charles Schleswig-Holstein-Sonderbury-Gluckburg-Saxe-Coburg-Gotha.

Ouch! And yes, you've guessed it: there was no Princess Diana either, as Di constantly reminded people who called her that. When she married, she became Her Royal Highness the Princess of Wales. Contrary to myth she was not stripped of her "HRH" (what is called a "style") when she divorced. She had a style because she was married to the Prince of Wales. When she divorced him, she automatically lost the style. (The same happened to Sarah, Duchess of York, after her divorce.) Diana's complaint was simply that she wasn't given a new HRH in her own right after her divorce.

But Diana herself had a hazy grasp of royal titles. She once suggested that when her son Prince William of Wales becomes king she would become "king mother". Not without a sex change she wouldn't. Queen mother does not mean "mother of the queen". It means "a former queen consort who is the mother of the current king or queen". A "King Mother" would somehow have had to have been a king and a mother, a miracle even for Diana!

Now for Camilla. When she marries the prince of Wales this Friday, she will automatically become Princess of Wales. Clarence House, correctly, has never said that she wouldn't. It simply said that she would be "called" Duchess of Cornwall, one of the many titles she would have anyway but which would not normally be used officially except in Cornwall.

The issue of her becoming queen is if and when Charles accedes to the throne is more complicated. Clarence House correctly says there is no law saying she must be queen. True, but there are over 1,000 years of precedent. To break with that you need to legislate, as the lord chancellor has effectively admitted. And that is where the fun lies. For it isn't just a British law to stop her becoming British queen that would be needed. But a Canadian law to stop her becoming Canadian queen; an Australian law to stop her becoming Australian queen, and so on. More than 15 states would have to change their law, and that would be a nightmare. Otherwise you could have the farce of Charles and Camilla flying the world, with Camilla asking the question "Am I in a Queen Camilla timezone or a Princess Consort Camilla timezone?"

The likely solution is simply that she will be queen, but as with "Princess of Wales", she simply won't use the title. There is precedent there. King George V's widow was officially Queen Mary the Queen Mother after his death, but insisted on simply being called "Queen Mary". And though she is officially HRH Princess Louise of Wessex, the Earl of Wessex's daughter is known simply as Lady Louise Windsor (minus the HRH).

So if you're confused about royal titles, don't worry. You are in good company. Most journalists get them wrong all the time. So expect to read about a non-existent Princess Camilla, married to a non-existent Prince Charles, who was formerly married to a non-existent Princess Diana.

Over Earl Grey tea in the palace, courtiers will mutter: "Can't someone out there please, just once, get the titles right?"

So there, guys, I've written them exactly as you explained to me many moons ago. Have I earned a last-minute invite to the wedding?