The acquittal yesterday of Dutch anti-Islamic politician Geert Wilders on charges of inciting hatred has split the Netherlands down the middle as effectively as the populist MP's right-wing rhetoric.

Judge Marcel van Oosten ruled that some of Mr Wilders' comments may have been "crude and denigrating" but they did not amount to inciting hatred against Muslims and remained within the boundaries of free speech.

Even Mr Wilders' most inflammatory statements, including the remark that "the core of the problem is the fascist Islam, the sick ideology of Allah and Mohammed as laid down in the Islamic Mein Kampf: the Koran", amounted to criticism of a religion and therefore were not illegal, the court decided.

The 47-year-old, instantly recognisable with his mane of light blond hair, sat impassively while the verdict was being read. But he smiled broadly when it was announced and waved to supporters as he left the Amsterdam court. "It's not only an acquittal for me but a victory for freedom of expression in the Netherlands," said the controversial MP, who has received numerous death threats and has to live under 24-hour guard. "Fortunately, you are allowed to discuss Islam in public debate and you're not muzzled."

But the verdict was fiercely criticised by immigrant groups and some liberal commentators. Farid Azarkan, of the SMN association of Moroccans in the Netherlands, said: "You see that people feel more and more supported in saying that minorities are good for nothing.

"Wilders has said very extreme things about Muslims and Moroccans, so when will it ever stop?"

Lawyer Gerard Spong, one of the first people to accuse Wilders of incitement to hatred, was disappointed. "We are thinking of going to the European Court," he said. "I think Wilders went too far. I was surprised and shocked when he said at the end of the trial that he had meant to be rude and insulting. That is an admission in itself."

But indicating how deeply divided the Netherlands is on the issue, even some left-leaning opposition MPs welcomed the verdict on the grounds it respected freedom of speech. Femke Halsema, a senior figure in the left-wing GroenLinks party, called the outcome of the trial "the right decision".

Another GroenLinks figure, MP Tofik Dibi, also welcomed the verdict and said he could not wait "to see Wilders get into a proper debate with the people who feel insulted by him".

Amsterdam sociologist Elsbeth Kalff said: "He has been told that he has been rude and offensive but it is on the border of what the criminal law allows. It is good. The Netherlands is, after all, a tolerant country and we should keep it that way."