ALMERE and Osdorp are two of the working-class suburbs that ring Amsterdam, modern planned towns of blocky flats and town houses interspersed with parks and football fields. In recent years upwardly mobile Muslim and Caribbean immigrants have been leaving the inner city for the suburbs, turning places like these into staging grounds for the Netherlands’ rocky integration process. It was here that the country’s latest racial tragedy took place.

After a match against a youth football club in Almere in early December, several teenaged players from a visiting Osdorp team pummelled and brutally kicked a volunteer linesman after an unexplained dispute. The linesman, the father of an Almere player, died the next day. He was white. His young assailants were ethnic Moroccans. The incident has touched off a month-long resurgence of religious and racial tensions that have preoccupied Dutch politics for over a decade. And it has resurrected the fortunes of Geert Wilders, a populist right-wing politician who best exploits those tensions.

Ethnic and religious conflicts have racked the Netherlands for years. Yet the latest flare-up came as something of a surprise. The euro crisis eclipsed the issues of immigration and Islam last year, leading even Mr Wilders to downplay his demands for banning the burqa and to emphasise anti-European politics instead.

The Dutch election in September led to a centrist coalition government. Mr Wilders’s Freedom Party took just 10% of the vote. But while ethnic politics may have quieted temporarily, the roots of the conflicts are as strong as ever. A report released in mid-December by the Netherlands Institute for Social Research found that social contact between white native Dutch and the main immigrant groups (Moroccan, Turkish, Antillean and Surinamese) has actually shrunk over the past 17 years. Half a century after the first Turkish and Moroccan guest workers arrived in the Netherlands, only 28% of ethnic Turks and 37% of ethnic Moroccans identify themselves strongly as Dutch. And while their Dutch language skills have improved, immigrant groups felt less accepted in Dutch society in 2011 than they had in 2002.

The authors pin much of the blame on “the image native Dutch have of Muslim groups”, which seems only to have worsened in recent years. But Dutch conservatives say immigrants themselves are to blame for their image. Crime rates among young Moroccan men are triple those of white Dutch youths.

In the aftermath of the football clash, ethnic politics leapt to the fore again. The national football association cancelled every amateur game in the country the next weekend, and with Mark Rutte, the Liberal prime minister, called for measures to reduce violence in sports. Mr Wilders attacked this as political correctness. “We don’t have a sports-violence problem, we have a Moroccan problem.” He called for the alleged offenders, all aged between 14 and 17, to be stripped of their Dutch citizenship and sent “back” to Morocco.

A string of other incidents over the past month have scratched ethnic sore spots. An Amsterdam newspaper reported that a social-housing corporation was creating “halal-flats” with partitions separating men and women. A Moroccan woman in a small town stabbed her daughter to death in a possible honour killing, triggering calls for closer police monitoring. And an amusement park established a Muslim prayer room.

All this has combined to push anxiety over race and religion back to the top of the political agenda. The latest polls give the Freedom Party 17% of the vote, tied with Labour for first place. Mr Rutte’s Liberals have slipped to third. Pundits speculating that Mr Wilders’s politics had grown stale may have written him off too early.