The extent of antisemitism in the UK is hard to gauge because there is a lack of accurate data, according to the Jewish community’s main think tank.

Despite a number of surveys carried out over the years, there remains a “distinct lack of clarity”, the Institute for Jewish Policy Research said in a new report, entitled “Could It Happen Here?”, this week.

Some sources showed that the level of antipathy towards Jews was “comparatively low and stable in the UK, even though other sources demonstrate that 2014 broke all known records for the number of antisemitic incidents.”

Other data suggested that fewer British adults held antisemitic attitudes than French, but that over the previous seven years more antisemitic incidents per head took place in Britain than in France.

During conflicts such as last summer’s Israel-Gaza War, the number of antisemitic incidents in the UK is usually three times above the monthly average, JPR said.

Antisemitic incidents usually rise by 30 per cent around the High Holy-Days.

Excluding these two exceptional periods, the number of antisemitic incidents has increased from 35 per month in 2004 to 51 last year, the report found.

“They may well indicate that levels of antisemitism in the UK have climbed over the course of the past decade,” JPR stated.

“However, one cannot rule out an alternative explanation – that the increase shown is due to an increased prevalence among Jews to report incidents in the first place.”

While Islamic extremists clearly pose a threat, the report says that “not enough is known about the extent to which their ideas, even in diluted form, permeate the Muslim population as a whole and whether the danger is growing, declining or stable over time”.

Calling for investment in proper research, JPR says the “Jewish community needs to steer away from knee-jerk reactions and ad hoc research enterprises. Monitoring trends in antisemitism requires more than having ‘being concerned’ or having good intentions.”

The alternative is wasted resources and persistent uncertainty “at the expense of greater clarity and, we believe, greater safety for Jews”.