From the supplemental material of a paper I covered in March, here are a couple of PCA plots of the first two principal components of the studied populations, with or without the Finns.
In the plot without the Finns, we see the expected British Isles -> Continental Europe differentiation in the order of Ireland, UK, Netherlands, along PC1. Swedes, and to a much lesser extent Danes deviate from this gradient in an orthogonal direction.
When Finns are included, PC1 now captures the major difference between them and the other Celto-Germanic populations which appear strikingly homogeneous along this component. The reason for the Swedes' divergence is now clear, as they are seemingly drawn towards the Finns, although the two clusters can be cleanly separated by a line at around PC1=-0.03.
It is fairly clear by now, that in northern Europe, there are two major distinctions (in that order): (i) between the Finns, and Finno-Ugrian influenced populations on the one hand, and the rest, and (b) a less important West-East gradient from Ireland to the Baltic.
The fact that factor (i) is the most important one pretty much vindicates the views of traditional physical anthropology since the time of Deniker at least. Despite the lack of data and statistical knowledge available at his time, Deniker, in the late 19th century, divided the light-pigmented northern European xanthochrooi of earlier classifications into two: the race nordique, associated primarily with the Germanic peoples, and the race orientale associated primarily with the eastern Slavs and Finns.
This classification scheme was continued by the better writers that followed, e.g., as razza nordica and razza baltica by Renato Biasutti, and as Атланто-балтийская раса (Atlanto-Baltic race) and Беломорско-балтийская раса (White Sea-Baltic race) in works written in Russian.