Europe was home to between 3.9 million and 4.8 million unauthorised immigrants in 2017, about half of whom lived in the UK and Germany, according to the first comprehensive estimate in more than a decade.
The Pew Research Center study, based on data from the 32 EU and Efta member states and international organisations, found the range was significantly higher than in 2014 (3 million to 3.7 million) but had fallen slightly since a 2016 peak of 4.1 million to 5.3 million.
The study also found that unauthorised immigrants in Europe came from many different countries, had arrived relatively recently and were mostly young and male.
Andrew Geddes, the director of the Migration Policy Centre at the European University Institute in Florence, said the study presented a “rigorous, robust and credible” picture of an issue that many Europeans had “lost trust and confidence in the capacity of their governments – and the EU – to deal with competently”.
Victoria Rietig, of the German Council on Foreign Relations, said there was agreement in Germany that unauthorised immigration was “bad for security, bad for the people concerned who live in the shadows, bad for social cohesion,” but that the debate had become “toxic and increasingly ideological”.
The study found that Germany, the UK, Italy and France, which between them represent about 50% of Europe’s total population of 500 million people, accounted for roughly 70% of unauthorised immigrants, with Germany and the UK alone accounting for about half.
The children of unauthorised immigrants were counted in the estimates, as were people with pending asylum applications whose future in Europe was uncertain. Most of these had arrived without permission, and a majority of claims were now being rejected, the report said.
Experts say public attitudes towards immigration are becoming more nuanced, even in countries where populist far-right parties are in government or challenging for power.
Geddes said that in most European countries people now recognised that immigration was “a complex subject with complex trade-offs – it’s not a binary question of open or closed”. A 2018 Pew survey found majorities in several countries backed deporting unauthorised immigrants but also supported taking in refugees fleeing war and violence, many of whom arrive without authorisation.