The Pithlord's ancestry, to the best of his knowledge anyway, is pretty much all from the British isles. In addition to the fact that this makes him pale when he avoids the sun (as he should) and red with peeling skin when he doesn't, it provides for an extreme lack of coolness. Some among my co-ethnics attempted to solve this problem by alleging that they were "Celts" with mysterious Celtic Druidic ways. This was a problem when most of that Britishness was from England, though, and how cool can Celts be anyway?
But now it turns out, at least if Stephen Oppenheimer can be believed about such things, that the British, including the English, are not really Celtic or Anglo-Saxon (except narrowly on the male Y chromosone line), but are basically Basques. Seems some of the ancestral population of Europe headed over to Britain at the end of the last ice age, and then was wiped out of continental Europe except for the Basque country a millenium or two later.
If I am not much mistaken, those who think that the Neanderthals have continuing descendents have always put a lot of emphasis on the Basques. Which would make Brits an unusually Neanderthal bunch -- a proposition most of the world would accept without hesitation.