THE Dutch festival of Sinterklaas on December 5th, the country’s most important children’s holiday, is turning into an annual slugfest of racial politics. The problem is the figure of Zwarte Piet, an impish clown with a black face who accompanies the bearded St Nicholas (“Sinterklaas”) on his rounds, distributing presents and biscuits. The character is derived from 17th-century paintings of Moorish slaves, and many Dutch with African ancestry find it offensive. Most white Dutch fail to see the problem, and react angrily to accusations that their tradition is racist. The conflict plays out in the media, the schools, the courts and at Sinterklaas parades around the country. And it has fed into culture wars between Dutch liberals and anti-immigration populists such as Geert Wilders.

Opponents of the tradition thought they had won a victory earlier this year, when a court ordered Amsterdam to bar Zwarte Piets from its Sinterklaas parade. But a higher court reversed that decision last month. Amsterdam, with its leftist politics and large immigrant population, has taken a conciliatory approach, ordering some Piets merely to smear their faces to suggest they have climbed down a chimney. (Many white Dutch use this just-so story to excuse the character’s skin colour, though it fails to explain his curly hair and thick, bright-red lips.) Other liberal Dutch are switching to multicoloured “rainbow Piets”. But in most Dutch towns, Zwarte Piet remains thoroughly blacked-up. At a Sinterklaas parade in the town of Gouda, protests by anti-Zwarte Piet activists led to 90 arrests.

The sharpest twist in the debate this year came from a Dutch documentary film-maker, Sunny Bergman. For her film “Our Colonial Hangover”, broadcast on December 1st on national television, she dressed up as Zwarte Piet in East London, eliciting ridicule and anger from locals (including a flabbergasted Russell Brand). The film also stages an experiment in which three young men, one white, one black and one of Moroccan ethnicity, each nonchalantly try to smash a bicycle lock at midday in an Amsterdam park. Passers-by question the black and Arab men and phone the police; they assume the white man has simply lost his key. Park employees even help him to cut the chain.

In a bicycle-mad country, the experiment has struck a nerve. It has also moved the discussion to the larger question of racial prejudice in Dutch society. Other events have brought ethnic tensions to the fore. In September, prompted in part by worries over Dutch jihadists, Lodewijk Asscher, the deputy prime minister, announced heightened scrutiny of four Dutch Turkish organisations that he suspects hinder integration, including a religious group, Milli Gorus. Two Dutch Turkish MPs from Mr Asscher’s Labour Party harshly criticised the move, and in mid-November the party expelled them. Turkey’s foreign ministry then issued a statement of concern over anti-Turkish “racism” in the Netherlands. That prompted a testy exchange between Mark Rutte, the prime minister, and his Turkish counterpart, Recep Tayyip Erdogan.

All of this grumpiness highlights the difficulty centrist politicians are in. They find it impossible to address their non-white constituents’ complaints over racism without angering Dutch whites who do not consider themselves racist. In the film, Mr Brand explains his shock at Zwarte Piet: “In this country we think of Holland as a very advanced nation, with advanced social principles.” So do the Dutch, which is one reason they have such trouble accepting criticism of Zwarte Piet.