So far in 2019, the world has witnessed two of the deadliest terrorist attacks in recent history. The first, on two Mosques in Christchurch, New Zealand, saw 50 Muslims slaughtered in cold blood during Friday prayers by a far-right terrorist. The second, a series of Islamist suicide bombings on churches and hotels in Sri Lanka on Easter Day, killed hundreds, many of them worshipping Christians.

As well as mourning the victims of these atrocities, it is important to think in very practical terms about how to stop the next attack. Until 2016, that was my job in the Metropolitan Police, ultimately as Head of SO15, leading the 1800 specialist police officers in the Met’s Counter Terrorism Command.

Understandably, in the wake of the New Zealand attack, some in the UK’s Jewish community focused on the resurgent far-right — asking whether a synagogue, rather than a mosque, might be the next target in Britain. It makes sense to consider the possibility of such an outrage. After all, it is only six months since the far-right attack on the Tree of Life Synagogue in Pittsburgh, Pennsylvania, which killed 11 Jews.

Another attack on a synagogue in San Diego last week left one woman dead, with the rabbi and another congregant injured. We also know that far-right extremism is on the rise in the UK — and far more organised than it once was — with the police warning last year of a threat “more significant and more challenging than perhaps public debate gives it credit for”.

A growing awareness of the scale of the far-right threat — and the fact that it is on the rise — is a positive thing. As are, on the face of it, some efforts by different religious groups to engage on the matter. To take one example, Jonathan Freedland and Mehdi Hasan have argued in the pages of the Guardian that Jews and Muslims face a perfect storm; that “together” they must face down the “common and deadly threat”.

No doubt this involves the very best of intentions. But there is also a need for absolute realism when thinking about security and extremism. We can only prevent terrorist attacks, and come up with the right policy responses, if we unflinchingly examine the true nature of what we are up against.

The truth is that the threat to Jewish communities from far-right extremism — though very real — is currently dwarfed by the threat posed to Jews in the UK by Islamist extremism. Anyone interested in interfaith engagement should bear that in mind. “Islamist terrorism predominates by scale,” as Andrew Parker, the Director General of the Security Service, MI5, put it recently.

Extremists who support far-right ideologies number around 500-600 across the UK, with a small hardcore of around 100 individuals suspected of having allegiance to National Action, the proscribed Neo-Nazi terrorist organisation which is of growing concern to the police and MI5.

Compared to the number supporting Islamist extremism, these numbers are relatively small. For example, Andrew Parker has spoken of the “growing pool” of 20,000 individuals known to MI5 and the national counter terrorism police network. The vast majority of these are Islamist extremists, whose allegiance has been to a global jihad of the sort articulated by Al Qaeda and Isis. Their warped theology promotes the targeting of violent attacks against Jews.

It is easily forgotten that Osama Bin Laden issued a fatwa as long ago as 1998 entitled “Declaration of the World Islamic Front for Jihad against the Jews and the Crusaders,” proclaiming that this was an “individual duty for every Muslim”. A series of mass-casualty attacks occurred in the years that followed across numerous states, the most notorious being the bombings in Tunisia (2002), Casablanca and Turkey (2003).

In 2017, history repeated itself, with Bin Laden’s son encouraging attackers to “look for Jewish targets everywhere”. Other Muslim leaders have made similar proclamations such as the Gazan scholar Dr Muhammad Suleiman Al-Farra, who said earlier this year that it is a religious duty to fight the Jews and “kill them wherever you may find them”.

Isis has also repeatedly focused on the targeting of “Jews and crusaders” and the first mass murder attack by Isis in Europe began with an attack against Jews in Toulouse in 2012.

Others followed in Brussels, Paris and Copenhagen, and many Isis Islamist plots against Jews have been disrupted since, not least the plot by Mohammed and Shasta Khan who were convicted in 2012 of planning an attack against the Jewish community in Manchester. More recently, after the declaration of a “Caliphate” in Syria in 2014, the then spokesperson for Isis, Abu Mohammad Al-Adnani, referred to President Obama as a “mule of the Jews” in a similar directive to kill “Western disbelievers”.

As Neil Basu, the current national Head of Counter Terrorism policing, told the Home Affairs Select Committee in October 2018, there are more than 700 live terrorist investigations nationally, 80 per cent of which are concerned with Islamist threats and 20 per cent “other threats” including a significant proportion of far-right investigations. In other words, the known threat from Islamist extremism is many times bigger than that from far-right extremism. That is without taking into account the seriousness of the threats being investigated. Any response from the authorities, or the Jewish community, should reflect that.

CST recorded 1,652 antisemitic incidents last year across the UK, of which just 5 per cent showed clear evidence of far-right motivation. A survey of 16,500 Jews in 12 member states of the EU in 2018 (the biggest survey of Jewish people ever conducted worldwide) is more revealing. The survey recorded the most frequently mentioned categories of perpetrators of the most serious incidents of antisemitic harassment experienced by the respondents as follows: someone they did not know (31 per cent); someone with an extremist Muslim view (30 per cent); someone with a left-wing political view (21 per cent); a colleague from work or school/college (16 per cent); an acquaintance or friend (15 per cent); and someone with a right-wing political view (13 per cent).

With this in mind, it makes little sense for those interested in protecting the Jewish community from extremism and terrorism to engage with Muslim groups unless it is part of an honest effort to confront Islamist antisemitism. Talk of a joint endeavour against the far-right risks distracting from a much bigger and more serious threat.

Instead, the Jewish community should continue doing what it has done for decades: standing up for common British values against all kinds of extremism, whether from Islamists, the far-left or the far-right.

Richard Walton is Senior Fellow at Policy Exchange and former Head of Counter Terrorism Command in the Met Police