See also the links to earlier discussions of the song above.

If recent genetic analysis is to be trusted, it does seem that there is a high proportion of Neolithic (pre-Celtic) blood in Wales. There seems to be a near relationship to the Basques; that doesn't mean, as people who are more conscious of fashion than science have assumed, that the Basques are "Celts" (they are nothing of the kind; their language isn't even Indo-European), but that most of the Welsh aren't "Celtic" at all. They were here long before Celtic languages or culture arrived, and, as Greg suggests, the highest concentration of the "aboriginal" population of Britain does appear to be in Wales; though it is rather more widespread throughout Britain and Ireland than people tend to imagine.

We still labour under the romantic nationalist fantasies of the 18th century. The sooner we can shrug off all that nonsense, the sooner we can begin to arrive at a proper understanding of where we are really from, and what we are.