The Vikings migrated to England because of poor land/soil quality in Scandinavia and there was a lack of land for younger sons. England had good quality land/soil.
England became part of Normandy's empire and was connected to France. England would remain strongly connected to France for the next 400 years by the Normans then Angevins.
1962 Immigration Act put a limit on black and Asian immigration and only allowed those with a skilled job lined up to migrate, slowing down immigration