EUROPEANS—their footprints fossilised on Norfolk’s coast 800,000 years ago—might be Britain’s oldest immigrants. But, as Britons campaigning for their country to leave the European Union have noticed, they also account for many of its newest. In 2004 Europeans made up 26% of all Britain’s foreign-born incomers; in 2014 they accounted for 48%. And whereas many of the country’s other immigrants slip, inconspicuous, into large cities, the latest generation—largely English-speaking, ever a short plane ride from home—have gone just about everywhere.

The big recent increase comes from Europe’s east. Eastern Europeans were once scarce in Britain. But in 2004, when it lifted work restrictions on eight central and eastern European countries, Poles entered in large numbers: in 2007 they peaked at 22% of Britain’s foreign inflows, and now number some 850,000, making them Britain’s largest group of foreign citizens. In 2013 Britain granted the same rights to Romanians and Bulgarians, and many predicted a similar “surge”. It did not happen: so far only around 230,000 have come.

Poles, suddenly and uniquely, had spread themselves across the expanse of the country, settling in improbable market towns, surprising the Northern Irish—who see relatively few immigrants—and going some way to reversing Scotland’s shrinking population. London holds 37% of Britain’s foreign-born population, but only 185,000 Poles live there: fully 80% live elsewhere in Britain (23,000 live in Northern Ireland and 82,000 in Scotland). Half Britain’s Romanians and just under half its Bulgarians, meanwhile, live in London, mostly gathering in Barnet and Brent.

INTERACTIVE: A guide to Europe’s migrant crisis, in numbers Poles had arrived at a time when their skills—mainly in agriculture and hospitality—and their willingness to toil for wages and in conditions that British workers spurned, matched the needs of rural employers. Recruiters often went to Poland to seek them out, teach them English and transport them over. They settled with little regard for history: earlier generations of Polish migrants, who had come to Britain after the second world war, were at first unwelcoming to the newcomers (“Closed, closed, closed,” says Jakob Krupa, a correspondent for the Polish Press Agency in London). Many of the new bunch came from small towns themselves, so places like Boston in Lincolnshire, which is now home to a lively Polish community, did not feel too strange. In any case, travelling in companionable groups, and planning to stay only a few years, they were prepared to live just about anywhere. Bulgarians and Romanians, meanwhile, work mainly in construction. The big cities, especially London, account for much of the industry’s demand, so that is where they have gone, settling in the outskirts where housing is cheaper (see map). The relaxation of employment rules in 2013 made little difference to their numbers, as self-employment, common in the construction industry, had been permitted since 2007, when the two countries joined the EU. (The number of Bulgarian-born in work actually fell in Britain in 2014.)

Unlike the Poles of 2004, who were forbidden from working in most other EU countries, Romanians and Bulgarians may work all over Europe. They also tend to plan to stay longer, says Stephen Drinkwater of the University of Roehampton, “so they are looking for a better fit from the start”. Trickling in ones and twos, people from Bulgaria and Romania have pooled close to their fellow countrymen. Many Poles started in basic jobs, but within an average of 18 months, says Heather Rolfe at the National Institute of Economic and Social Research, they found something better. In towns like Wisbech, in Cambridgeshire, Polish businesses have transformed rundown high streets. Some, keen to fit in, diligently take tea (with lemon) at five. In 2004, according to the International Passenger Survey, one in ten intended to stay at least three years. In 2014, nearly half did. Romanians and Bulgarians arrived in a country used to eastern Europeans, and face less prejudice. They are on average less educated than Poles. But 74% are in some sort of employment, almost the same rate as Polish migrants, 80% of whom are in work. And between 2013 and 2014 there was a sevenfold increase in national insurance numbers issued to Romanians, and a threefold increase in those given to Bulgarians—a sign they are shifting out of self-employment. Anecdotes of porters becoming managers within a year or two abound. And as Brexit campaigners worry European migrant flows are too high, Britain’s food and drink companies, big migrant-employers, fret they are too low. Like migrants from western Europe, those from the east are more likely to be graduates than the British-born. Around three-quarters come for work, nearly half with jobs lined up before they arrive. A new deal limiting benefits for EU migrants is unlikely to make much difference to inflows: fewer will get in-work benefits, but this will be offset by a planned rise in the minimum wage; in any case Britain’s job market, more flexible than the rest of Europe, remains the main attraction.

Only limits on free movement from the continent would change things. That happened once before in Britain, as a result of rising sea levels more than 200,000 years ago. Now, as the country threatens to leave the EU, it may yet happen again.