"Half of Brits have immigrant ancestors"

Headline from The Telegraph, reporting on the results of a survey by ancestry.co.uk last month. The Daily Mail has more details:

[British] who investigated at least four generations of their family tree revealed just over half had recent immigrant ancestors.

The majority came from our European neighbours, including a quarter from Ireland, one in ten from France and a similar number from Germany.

But distant countries which featured high on the list included Canada, where one in 20 of us can trace a family member - a reminder of our close links with the Commonwealth country.

Around one in 30 have American blood in their veins - the country which gave us Christmas turkey.

[. . .]

Yet most of us remain unaware of the rich mixture of nationalities in our families. In all, 84 per cent of us know nothing about our foreign background, says ancestry.co.uk which commissioned a poll of 2,500 individuals, including 500 who had investigated their family trees.

I don't know how representative of Britain ancestry.co.uk's sample is, but I'm aware of other surveys showing large proportions (19% to 77%) of Londoners report Irish ancestors.

Most of the reporting on this story conflates/equates immigration from neighboring European countries and immigration of non-Europeans, which is of course nonsense. This survey bears notice, however: the presence of a significant recent non-English element in England complicates efforts to make historical inferences from genetic surveys of the present-day general English population. The People of the British Isles project, sampling rural people "whose parents and grandparents were all born in the same locality", should allow clearer results than studies based on medical samples.