The truth is discomforting: hatred and intolerance are moving into the mainstream in Europe.

An Afghan migrant is stabbed in the heart on the streets of Athens. Black-shirted paramilitaries linked to Hungary's third-largest political party march through a Roma neighbourhood shouting, "You will die here." A neo-Nazi gang commits a string of murders of Turkish immigrants in Germany. An ideologue driven by hatred of "multiculturalism" kills 67 mostly young people on a Norwegian Island.

It may be comforting to see these incidents as isolated, disconnected or driven by local events. But the truth is more discomforting: hatred and intolerance are moving into the mainstream in Europe.

Intolerance in Europe manifests itself in support for extremist parties and violence and discrimination against minorities and migrants. Rather than tackling the problem head on, Europe's leaders often downplay the problem or blame the victims. But concerted steps are needed to stop the violence and discrimination and curtail the corrosive influence of racist parties, without limiting freedoms of speech and association.

In many European countries, extremist parties- espousing racist, anti-immigrant or anti minority policies-are part of the political landscape. Their platforms vary, with some corresponding to traditional far-right parties. But they frequently define themselves by strong opposition to particular groups, including Muslims and immigrants (particularly among parties in western Europe) and Roma (in eastern Europe).

The neo-Nazi Golden Dawn party entered the Greek Parliament in June, securing 7 percent of the popular vote. In France, the National Front won almost 18 percent of the vote in the April 2012 first-round presidential elections. In the Netherlands, the Freedom Party caused the government to collapse in April 2012, withdrawing its support from the ruling coalition (though it lost ground at the polls in September). Until recently, extremist parties were also part of government coalitions in Italy and Switzerland, and earlier in Austria. Similar parties have made significant gains in Denmark, Sweden, and Finland, and had electoral success in the 2009 European Parliament elections in Hungary, the UK, and elsewhere.

A 2011 study by Chatham House indicates that support for such parties is a long-term trend, in many cases pre-dating the economic downturn. A 2012 study by the European Network Against Racism notes that while some European countries have long had successful far-right parties, extremist parties have had increasing success in the last decade in countries where they traditionally had little support at the polls.

Intolerant political rhetoric is not confined to extremist parties. Too often, mainstream European politicians use intolerant or coded language about unpopular minorities. They justify such speech on the ground that the failure to discuss issues like immigration creates political space for extremist parties. But far from neutralizing extremist parties, this kind of rhetoric from government ministers and other mainstream politicians legitimizes their views, sending a message to voters that xenophobic, anti-Muslim, or anti-Roma sentiment is acceptable rather than a cause for shame.

Human Rights Watch staff witnessed a Greek MP from a mainstream party describe migrants as "cockroaches" during a Greek Parliamentary committee hearing in November on violence against migrants.

Silvio Berlusconi, then Italy's prime minister, said in January 2010, that, "A reduction in [the number of] foreigners in Italy means fewer people to swell the ranks of criminals." In 2010, the French interior minister at the time justified dismantling Roma settlements, asserting they were sources of "illicit trafficking, children exploited for begging, prostitution or delinquency," while the Romanian foreign minister made public statements suggesting that Roma are genetically predisposed to criminality. The same year Chancellor Angela Merkel of Germany used a major speech to tell migrants in Germany: "We feel tied to Christian values. Those who don't accept them don't have a place here" (although in 2012 she softened her tone, saying that Muslims are part of Germany).

Just as mainstream politicians sometimes echo the intolerant views commonly associated with extremist parties, there is evidence to suggest that such views are shared far more widely than those who vote for extremist parties. In polling data from 2010 by the Friedrich Ebert Foundation, half of those polled across eight EU states -- including France, Germany and the UK - shared the view that there are too many immigrants, and more than 40 percent concluded the same about Muslims.

Anti-Semitism and anti-Roma sentiment are also widespread. In Hungary, 68 percent of those polled in December 2012 said they would not allow their child to be friends with a Roma child. The numbers who would oppose a child's friendship with African and Jewish children were slightly lower (58 and 46 percent respectively) but still deeply alarming, not least because it suggests anti-Roma, anti-migrant and anti-Semitic prejudice are widespread. German, Swedish and UK authorities all recorded large numbers of anti-Semitic incidents in 2010, the most recent data available.