If anyone doubted that chiller winds were blowing over Europe on immigration and related issues, the speech given at the weekend by Germany's Chancellor, Angela Merkel, offered a powerful corrective. For obvious historical reasons, German leaders have always been careful about broaching the subject of multiculturalism in general and Germany's Turkish minority in particular, preferring, if at all possible, to steer away.

Addressing a youth gathering of her centre-right CDU party, however, Ms Merkel made herself startlingly clear. Attempts to build a multicultural society in Germany, she said, had "utterly failed". Immigrants had to do more to integrate – including by learning German.

Now it might be said that Ms Merkel was being tooo hard on her country. While there are areas of some cities which seem more Turkish than German, there are success stories, too, of descendants of 1960s' Gastarbeiter comfortably integrated into German life. The picture is not all bleak, nor has Germany failed more conspicuously than many other European countries.

Ms Merkel's speech, though, was a bellwether, and the clearest sign yet that the debate on migration and multiculturalism is now open, even in Germany where it was practically taboo. And while Ms Merkel's forthright words suggest that she intends to lead the debate from now on, it was not she who started it. This dubious honour belongs to Thilo Sarrazin, a former boardmember of the Bundesbank, whose recent book, Germany Abolishes Itself, and attendant magazine articles, shocked the country's establishment, first, by what many saw as its racist content and, second, by its swift rise to the top of the best-seller list.

Mr Sarrazin resigned from the Bundesbank last month, after condemnation from Ms Merkel, among others. That she has now addressed the subject herself, however, demonstrates how quickly the context has changed. Mr Sarrazin raised spectres that were too dangerous to be left to become flesh and blood on the far right. They had to be tackled head-on.

Germany now joins France, Belgium, the Netherlands and – so far, to a lesser extent, Britain – in questioning the multicultural approach adopted by governments for many years. If integration is now to be the focus, however, the effort will have to be two-sided. As well as requiring migrants to do more, governments and the indigenous population will have to try harder, too. And this will take funds – for language tuition, better schooling and homes – at a time when money is in very short supply.