Europeans have been warned to remember the continent’s history of xenophobia and racism when they go to the polls next year.
Jose Manuel Barroso made the comment amid expectations anti-EU and protest parties will do well in elections for the European Parliament in May.
Barroso, president of the European Commission, said the economic crisis and unemployment had given populist forces a platform.
He said: “What we don’t like is the discourse that is sometimes behind anti-European slogans, a discourse that is promoting what I call negative values, things like narrow nationalism, protectionism and xenophobia. That is a concern.
“We should not forget that in Europe, not so many decades ago, we had very, very worrying developments of xenophobia and racism and intolerance. So I think everybody that has European principles should be worried about some of these movements.”
Polls suggest right-wing parties with strong positions on immigration could do well.
In Britain, the UK Independence Party is predicted to come first or second in the elections, although a lot can change with seven months still to go before the vote.
In France, Marine Le Pen’s far-right National Front has pulled away from the two mainstream parties and according to one recent poll is expected to win the election.
Besides the right-wing forces, there are far-left or protest movements in Greece and Italy that have strong popular backing, as well as single-issue parties such as Germany’s anti-euro AfD that are expected to secure representation in the 760-seat European Parliament, the EU’s only directly elected body.
Barroso added he was confident the mainstream political parties would remain largely dominant in the new parliament, and urged them to speak out for European values if they were to keep extremists in check.
“The pro-European forces…need to take the lead, not give the initiative to extremist forces, and explain in a rational and reasonable way what Europe brings,” he said. “That is why we are asking the so-called mainstream parties to have the courage to get out of their comfort zone, to think that today, at a time of crisis, we cannot take the European Union for granted.”