I'll continue the digression here.Kevin Thurlow wrote:"Given that Elizabeth I of Scotland is Head of the Commonwealth, one would hope not!"
A bit of a digression, but she's Elizabeth II in Scotland as well. I read somewhere that as James VI (Scotland), who was also James I (England), was followed by James II (England), then Scotland and England became one big happy family, so the next King James will be James VIII. This may be complete rubbish, and may well be overtaken by events of course.
Around about the time of the current queen's coronation, there was some disgruntlement over the proposal that she be styled Queen Elizabeth II given there had been no previous Queen of Scots called Elizabeth. This led to some bombing of post boxes (and to this day, you won't find post or pillar boxes in Scotland with the cypher EIIR thereon).
The current queen's title in Scotland was challenged in the courts by John MacCormick, with the ruling that the matter was subject to Royal Prerogative, which I think means that the Monarch can do whatever (s)he wants.
It was suggested in the House of Commons in 1953 by the Prime Minister that future monarchs would use the higher of the ordinals appropriate to the Kingdom of Scotland and the Kingdom of England.
There is precedent for this elsewhere, with Vittorio Emanuele II being the first King of Italy of that name. Mr Churchill sidestepped the issue of a future monarch called Llewellyn and why some previous King Edwards (such as Edward the Confessor) don't count.
Overall this would imply that the next King James would be James VIII (although I believe the old pretender also used that title).
I can't tell you how disappointed I was when the Earl and Countess of Strathearn didn't put this theory to the test and name their first-born Alexander or David. Of course, there is nothing to stop George (or indeed William or Charles) from choosing a different regnal name if the time comes.