I recently read an article that said that the Cornish Language very nearly went extinct in the early 19th century. What if it had? How would this change the culture and indentity of the people of Cornwall, and of Britian as a whole?
You'd have to eliminate the attempted revival by a group of villagers in the Lamorna area around 1788; it started out very small, but it ended up gathering steam and by 1860, had become recognized by the British government: Now, Cornish is spoken by about 2.7 million people as one of their primary tongues worldwide.
And Kenwyn Davies, the failed soccer star? As I recall, he was the one who first attempted to gather support for a kingdom in Cornwall, back in 1947. He didn't succeed, of course, as his rather strange version of traditionalism alienated most of his fellow Cornishmen, primarily due to his over-the-top racism and the fact that he was a staunch opponent of labor rights and social welfare; that region had been reliably Labour for over 40 years and had the second highest standard of living outside the major cities.
He later founded the "True Cornish" movement in Australia in 1959, but that, too, failed: His Royalist sentiments didn't sit well with many Aussies, given that they spent over a decade fighting a nasty civil war between Royalists and the Republican movement(who eventually won); the fact he'd become a fascist hadn't helped either. I imagine, though, were it not for Davies, Cornish might have even more of an influence and might have gained a better foothold Down Under, too.