h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Although the current Queen Elizabeth is the second queen of England to bear that name and the first queen of Scotland to do so, her title is Queen Elizabeth the Second of the United Kingdom. This annoys a lot of Scottish people, because the first Queen Elizabeth was never a queen of Scotland.

The present queen should be Queen Elizabeth the First of the United Kingdom, but showing a typically English bias, she chose to call herself "the Second". She's the monarch. She can call herself what she likes.

When Charles becomes king, will he choose the correct "King Charles the First" or will he take the wimp route and be "King Charles the Third"?

If you wanted to be fussy you could say why was King Edward I of England called King Edward I, when England had already been ruled by several Edwards in Saxon times, after England was united after the Viking conquest of the North... It's just one of those things.

Could you not argue that she is the 'second' in the United Kingdom since there has previously been a Queen Elizabeth in the United Kingdom (admittedly she only queened over a part of it).
Of course that would mean you'd need to add up the total numbers of English and Scottish monarchs of a given name when determining the number and that isn't done either.

Zathras

Charles would never call himself Charles I. Not after what happened to the last one.

I heard he was thinking of calling himself by his middle name if/when he gets the throne because of the public's negative associations with the name 'Charles' when applied to kings. ( I don't know what it says about a king who's willing to change his name because of 'negative associations'!) Besides, I hope William's going to go next; the Queen'll probably hang on to the throne until way long enough after he comes of age.

Changing names to avoid negative associations? the Royal family's name of Windsor is an example of just that - it was changed in or around the first World War because the original one was too german sounding. The Scots shouldn't have any problems with Charles the Third - the first two Charlies were kings of Scotland too, and indeed they were the son and grandson of a Scot.

Didn't the United Kingdom come into being with the Act of Union in 1802 (or thereabouts)? So Lizzy would be Elizabeth the First of the United Kingdom....

The Act of Union was 1707 but the thrones had been united from 16humptytump when James Vi of Scotland became also the I of England. He was specifically called the VI and I, so those following ought to be as well. I think it fell into disuse with the two Charlies (a right pair of) as, indeed, they were the first in either nation to use that name. Of course this doesn't cover Wales or Ireland.

Ireland never had its own king, unless you count Brian Boru. Since all the kings and queens of England claimed rights over Ireland too (since about 1250), the question does not arise.

True, but they also claimed Kingship of France and Scotland as well.
Oh yes, and the Royal Family were called Saxe-Coburg Gotha (from Prince Albert) before the 1914. Probably just as well that they changed it, it would never fit in a Sun headline.