He has spent the past decade studying European immigration, travelling widely and reading voraciously in an impressive variety of languages. His controversial new book repeatedly echoes Powell’s warnings all those years ago. Mr Caldwell argues that “Western Europe became a multi-ethnic society in a fit of absence of mind.” European policymakers imported people to fill short-term job shortages. But immigrants continued to multiply even as the jobs disappeared: the number of foreign residents in Germany increased from 3m in 1971 to 7.5m in 2000 though the number of foreigners in the workforce did not budge. Today immigrants account for about 10% of the population of most west European countries, and up to 30% in some of Europe’s great cities.