In the UK we are nearly all immigrants, really. It just depends upon how far back you go with your research.
My genetic test results are fairly typically 'English' - a mix of Northwestern European, Scandinavian, French and German, Irish and British with a 0.2 percent of North African.
SANGOMA IN Lebowakgomo[[[+27°81°874°4558]]]?IN MANKWENG,POLOKWANE,Loius Trichardt
To think that London, or anywhere else for that matter, does not belong to any one demographic