The map above is from the People of Britain project at Oxford (Donnelly, 2015). They tried to find people who lived near to where all their grandparents had lived, and found 2,039 individuals. Our interest is finding the relationship between ethnolinguistic groups and their bloodline.
The south and east of England form one gene pool. Genes of Angles and Saxons dominate are uniformly spread. However, more than half of this gene pool derives from pre-existing inhabitants of the region. London is too diverse to be part of this pool.