The British Monarchy was formed when King James VI of Scotland inherited the throne of England in 1603. Prior to that, Kings and Queens of England and Scotland had reigned separately. When King James came to the throne of England, he became known as King James I & VI (the first of England and sixth of Scotland).
From 1603 until 1707, England and Scotland’s thrones remained in ‘personal union’ because the King/Queen of England also was the King/Queen of Scotland – the thrones were linked, but not through law. Where applicable, Monarchs held two regnal numbers – one for England and one for Scotland. For example, King William III was known as King William III & II because whilst he was the third King William of England, he was also the second King William of Scotland.
When the 1707 Act of Union was passed, the Kingdom of Great Britain was created and the practice of two separate regnal numbers being used stopped, coincidentally, for the next few reigns at least, the regnal numbers of Kings and Queens of Britain matched that of Scotland.
Little was heard of the debate from thereon in until the reign of our present Queen when Scotland said because there had never been a Queen Elizabeth of Scotland, the new Queen should be known as Elizabeth I & II, not just Elizabeth II. This debate was risen in Parliament in 1953 and special measures were explained by the Prime Minister, Winston Churchill (which we’ll come onto in a minute).
Because of this disagreement over the regnal numbering of our Queen, Scotland still refuses to refer to her as Elizabeth II. On Scottish postboxes, for example, it would ordinarily display the Royal Cypher, though because that displays the symbol ‘EIIR’, just the Crown of Scotland is displayed on postboxes and other places which would ordinarily carry the Royal Cypher.
In fact, this disagreement was so ferocious that the argument is referred to as ‘The Pillar Box War’.
Now, back to how this was settled. On 15th April 1953, Hansard (the document that records what was said in Parliament) recalls that Churchill says, “It would be reasonable and logical to continue to adopt in future whichever numeral in the English or Scottish line were higher. Thus if, for instance, a King Robert or King James came to the throne he might well be designated by the numeral appropriate to the Scottish succession.”
To put this into basic terms, Kings and Queens of the United Kingdom will, in future, be known by whichever numeral is higher in England or Scotland. For example, if another King James came to the throne, he would be the third King James of England but the eighth King James of Scotland, thus he would be known as King James VIII of the UK. But, if there were for example another King Henry, he would be the first King Henry of Scotland but the ninth of England, making him King Henry IX of the United Kingdom.
In effect, though, it so happens that for the next few generations at least, the numerals for Kings of the UK either match in England and Scotland, or the English numeral is higher. For example, Prince Charles should become King Charles III, there have been 2 Kings Charles in England and Scotland – Prince William should become King William V, where there have been 5 King Williams of England and 4 of Scotland, and Prince George should become George VII, where an equal number have reigned over England and Scotland.
Unless Prince George’s heir is named James or Robert or another name of previous Kings of Scotland, the effect of this arrangement may not be felt for hundreds of years, however.