"I never could stomach these nationalists," Merlin tells Arthur in The Once And Future King. "The destiny of man is to unite, not to divide."
But in a world of ever-increasing human cooperation, the United Kingdom is discussing a break-up.
Many English and Scots say their countries would be better off without the other, but this debate isn't really about economics - it's about nationalism. It's an easy concept to sell because people want to believe 'we' are clever, brave and resourceful, and 'they' are holding us back.
But are we really going to break up the United Kingdom, which is divided by borders drawn virtually at random hundreds of years ago, just to serve petty patriotism?
These comparatively tiny islands built the greatest empire in history, defeated perhaps the most evil regime which has ever threatened humanity and has led the way for centuries in the development of democracy and the progress of science. If the country has declined in recent years, it is by comparison with the enormous world powers which have emerged - a problem that can hardly be solved by breaking into tribes ourselves.
Sport is ever-important to the UK's national identity, and the example of football offers powerful evidence that we are stronger united. Imagine the nation which could have boasted George Best, Bobby Moore, Kenny Dalglish and Ryan Giggs. That's not necessarily a case for Team GB - as rivalries like those between the home nations are what make sport interesting - but there's no doubt a united team would be stronger than its individual parts.
The same applies to the nation as a whole; the difference is that political unity really matters. Devolution is one thing, and probably a good one as many aspects of government are best done as locally as possible, but divorce would be a sad end to this wonderful union.
In The Once And Future King, Merlin warns Arthur that his enemies "want to smash up what we may call the United Kingdom into a lot of piffling little kingdoms of their own."
Arthur resisted them, and so should we.