Although the slump that followed the 1973 oil shock removed the urgent need to recruit labour, the Dutch accepted that the "guest workers" in the country could remain. The policy was to create a multicultural society in which cultural and ethnic differences were accepted and appreciated.

Some immigrants came from former Dutch colonies. The two largest groups, however, Turkish and Moroccan, had no historic links with the Netherlands. The Dutch nonetheless accepted the reunification of families, and the practice of marrying partners from the country of origin, even though these can have an eight- or tenfold multiplier effect on overall numbers. Asylum seekers then arrived, in numbers that escalated from 3,500 in 1985 to over 43,000 in 2000.

The figures were pro rata among the highest in the EU. Illegals came, too, mainly after 1990, with estimates running from 100,000 to 200,000. The Dutch supplied funding for mosques, religious schools, language courses and housing. They passed special legislation so Moroccans could have dual nationality, as Moroccan nationality is inalienable under Moroccan law. Political correctness, of the sort that produced Harry Enfield's famously relaxed Amsterdam policemen, reigned. Issues felt at street level — immigration, crime, culture, national identity — were seldom discussed by the political elite.

No longer. A sea change has taken place. It was evident after the death last month of a young Dutch Moroccan, identified only as Ali El B. Several hundred Moroccans congregated on the street where a driver had run him over, reversing into him after he had stolen her bag. They had made a shrine on the pavement, with flowers and candles, and there was talk of racism and murder. The crowd set off on a march to pay their respects at a mosque not far away. The boys were in a long gaggle at the front. The girls, neater, were in disciplined ranks at the rear. Some had Moroccan flags draped over their shoulders. They chanted in Arabic for a while, and passers-by looked and scurried on.

The mosque was on the ground floor in a row of old gabled houses, some converted into offices, that looked out over a broad waterway. A racing skiff, a pair, was splashing through the wavelets thrown up by a blustery gale. Television cameramen darted round the crowd as it milled outside the mosque. An elderly Dutchman looked down from his flat at the sea of hoods and scarves and red-and-green flags, with an utterly forlorn expression.

Nobody doubts that Ali El B would once have become a martyred innocent. Now, attempts to portray him like that were sat on fast and hard. The fiercest comment came from Geert Wilders. The hard line this right-wing MP takes on immigrants and terrorists has made him the fastest-rising star in the political firmament.

It has also brought threats of beheading from radical Islamists, so he is now shackled to six bodyguards and has secure lodgings on army bases. "All Moroccan troublemakers should be expelled," Wilders says. "The government wants to expel terrorists. The same process should be used for street terrorists like Ali El B. Detain them, de-naturalise them and deport them." Wilders is a firebrand. Rita Verdonk is the minister for immigration and integration, and a mainstream Conservative. She, too, is implacable. "If the boy hadn't stolen the bag," she says, "he'd be riding around on his scooter today."

But the real pointer to how far Holland has shifted comes from Job Cohen, the mayor of Amsterdam. Cohen is Labour, from the party that personified political correctness and the more-the-merrier, they-can-do-no-wrong approach to immigrants. "We have to admit," the mayor says, "that this was not a sweet and blameless youth, to put it mildly."

The consensus has shifted across the board. In a country that can still seem a parody of itself — a magistrate ruled recently that an armed robber was entitled to a tax rebate on the cost of his gun as a tool of his trade — even the leader of the Green party has called for it to be illegal for Muslims to import spouses through arranged marriages. Integrated teams, drawn from the police, social welfare and housing offices, are used to locate and arrest illegals. Social welfare knows who is drawing benefit, housing offices have addresses, and police check for criminal records. The number of asylum seekers has been slashed from 43,000 to 10,000 a year, nine-tenths of whom have their applications rejected.

Multiculturalism is damned. A recent poll found 80% in favour of stronger measures to get immigrants to integrate — and 40% said they "hoped" Muslims "no longer feel at home here".

How did this happen? The first open shift came in 2001, with 9/11. Frits Bolkestein, the leader of the VVD Conservative Liberals, had struck a chord in the 1990s with his insistence that immigrants conform to western culture, but immigration issues were largely the preserve of "racists" and "crypto-Nazis" on the political margins. Then came reports that the atrocities in New York and Washington had been greeted with cheers in parts of Rotterdam. Forum, the Dutch institute for multicultural development, commissioned an opinion poll of Dutch Muslims. It showed that 48% had "complete understanding" and 27% "some understanding" of the attacks. Overall, only 62% disapproved. Wim Kok, the then prime minister, expressed his shock. The poll was said to be "unbalanced".

Another was held. This found that, although only a small number of Turkish and Surinamese Muslims supported the attacks, 26% of ethnic Moroccans approved of them.