Jewish leaders accused the European Union yesterday of covering up the true scale of anti-Semitic violence carried out by Muslim youths, reigniting a controversy over Europe‘s failure to confront Islamic extremism at home.

A study released by the EU‘s racism and xenophobia monitoring centre astounded experts by concluding that the wave of anti-Jewish persecution over the last two years stemmed from neo-Nazi or other racist groups.

"The largest group of the perpetrators of anti-Semitic activities appears to be young, disaffected white Europeans," said a summary released to the European Parliament. "A further source of anti-Semitism in some countries was young Muslims of North African or Asian extraction.

"Traditionally, anti-Semitic groups on the extreme Right played a part in stirring opinion," it added.

The headline findings contradict the body of the report. This says most of the 193 violent attacks on synagogues, Jewish schools, kosher shops, cemeteries and rabbis in France in 2002 - up from 32 in 2001 - were "ascribed to youth from neighbourhoods sensitive to the Israeli-Palestinian conflict, principally of North African descent.

"The percentage attributable to the extreme Right was only nine per cent in 2002," it said.

The report on Belgium said most of the fire-bomb and machine-gun attacks on Jewish targets were the result of a spillover from the Palestinian intifada.

The European Jewish Congress accused the EU watchdog of twisting data from the 15 member states to suit its own ideological bias, describing the report as a catalogue of "enormous contradictions, errors and omissions."

"We cannot let it be said that the majority of anti-Semitic incidents come from young, disaffected white men. This is in complete contradiction with the facts recorded by the police," it said.

The EU suppressed a report last year by German academics concluding that Arab gangs were largely responsible for a sudden surge in the anti-Jewish violence, allegedly because the findings were politically unpalatable.

Victor Weitzel, who wrote a large section of yesterday‘s far more detailed study, told The Telegraph that the latest findings had been consistently massaged by the EU watchdog to play down the role of North African youth. "The European Union seems incapable of facing up to the truth on this," he said. "Everything is being tilted to ensure nice soft conclusions.

"When I told them that we need to monitor the inflammatory language being used by the Arab press in Europe, this was changed to the ‘minority press‘.

"Honestly, it‘s incredible," he said.

Mr Weitzel‘s 48-page section - compiled with a Polish academic, Magadalena Sroda - is the fruit of months of interviews with Jewish leaders across Europe. While far-Right and traditional "Christian" forms of anti-Semitism still exist, the report homes in on a new form of "anti-Zionist Left" prejudice.

This demonises Israel and subtly leaks into prejudice against all Jews. The study describes Belgium as a country where anti-Semitism has become almost fashionable among the Left-leaning intelligentsia.

But most of the report focuses on Jew-baiting by Muslim youths. It paints an alarming picture of daily life for France‘s 600,000 Jews, the EU‘s biggest community.

In schools, Jewish children are beaten with impunity, and teachers dare not talk about the Holocaust for fear of provoking Muslim pupils, it said.

Britain, which saw a 75 per cent rise in incidents last year, was gently rebuked for hesitating to take "politically awkward" measures against Islamic radicals.

"The government is very anxious not to upset the Muslim community," the report said.