Originally Posted by
alnortedelsur
I think some ancient population that spread from Iberia was widespread in British Isles (and probably other parts of Western Europe) in the far past (maybe some pre-indo European element that peaks in modern Iberians?), but it was very absorbed/diluted by different waves of more recent Indo-European migrations. South west England and Wales were relatively less exposed to those waves, including Celts, Anglo Saxons, Normans, Viking raids and what not, than the rest of Great Britain and Ireland, due to their particularly isolated location in westernmost corners of Britain, and not facing open sea (contrary to England, the rest of Scotland and Ireland). So, even though, at the end they got a lot of those north/central Euro contributions, that primary pre-Indo-European component (peaking in modern Iberians) wasn't as much absorbed/diluted in there as in the rest of British Isles and Ireland. That's in my humble opinion what would explain them being the closest to Iberians compared to the rest Britain/Ireland.