Interesting to read this:
The analysis also springs some surprises. There was no single Celtic population outside the Anglo-Saxon dominated areas, but instead a large number of genetically distinct populations (see map). The DNA signatures of people in the neighbouring counties of Devon and Cornwall are more different than between northern England and Scotland. And there are also unexpectedly stark differences between inhabitants in the north and south of the Welsh county of Pembrokeshire.
Interesting because of a book I have [Book of General Ignorance], which asks how long have the Celts lived in Britain?
Since June 21st, 1792.
It was then that a group of London bards staged a ceremony on Primrose Hill, involving a stone circle made from pebbles, claiming they were reviving a ritual stretching back to the ancient Celtic nation and its Druids.
Prior to this, there is no record of the word Celt having been used to describe the pre-Roman inhabitants of Britain or Ireland and it was certainly never a term they used to describe themselves.
The word Celt was coined by the Greek historian Herodotus in 450BC, when he described the peoples of the headwaters of the Danube, north of the Alps.
Edward Lluyd was apparently the miscreant who spread the Celtic myth.