Bad historical population genetics?

Nick Wade has a new article which draws upon the two new books about the genetics of the British Isles, Saxons, Vikings, and Celts, by Bryan Sykes, and The Origin of the British, by Stephen Oppenheimer. The gist is that the British peoples are genetically very similar, and predominantly the descendents of post-Ice Age settlers who swept up along the Atlantic seaboard from the "Iberian refugia".^1 To a first approximation this story is about right, the various studies seem to be converging upon the finding that most Britons and Irish are closer to each other than they are to continental populations (i.e., the English are closer to the Irish than their "fellow" Germanic peoples), and, they are closer to the peoples of southwestern Europe than they are to those of southeast or northeast Europe. But beyond the broad brushes there are fine grained details, and that is what Sykes and ...