Terror Data: US vs. UK

In April 2013, three people died and more than two hundred and sixty were injured in the Boston Marathon terror attack. At the same time in the UK, eleven men were sentenced for their roles in a large al-Qaeda–approved suicide plot in Birmingham to explode eight bombs concealed in backpacks, while members of another terror group were sentenced for a series of terrorism offenses, including potential attacks against British troops. A month later, a British soldier was indeed murdered on the streets of London by two radicalized men yelling, “Allahu akbar.” These events are only the latest that show the US and the UK face very similar ideological challenges from terrorism. Yet the backgrounds of the individuals posing this challenge differ greatly, as two recent studies we have conducted show. One study, published earlier this year, covered all those convicted of al-Qaeda and al-Qaeda–inspired terrorism in US civilian and military courts and those who committed suicide attacks on US soil over a fifteen-year period. A similar study we published in 2011 covered Islamism-related offenses in the UK between 1998 and 2010.

The fact that these most recent offenders were almost all male could have been expected. So too the fact that they were also young, especially in the UK, where sixty-eight percent of individuals we studied were under thirty at time of offense, compared to fifty-seven percent in the US. What was more surprising was that, in both countries, those involved in terror plots were mostly citizens—a contradiction of the common image of terrorism being perpetrated by foreigners. In the UK, sixty-eight percent of individuals who committed offenses were British citizens, while in the US it was fifty-four percent.

Most distressing, it was three British citizens (and one British permanent resident) who committed suicide attacks against the London transport system in July 2005, killing fifty-two people. Homegrown terrorists plotted other potentially lethal, yet ultimately unsuccessful, attacks—such as the plot originated in the UK to blow up multiple transatlantic flights using liquid bombs in 2006; and the attempt by Faisal Shahzad, an American citizen, to detonate a car bomb in Times Square in May 2010.

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Criticism has been leveled at the FBI for failing to take the threat of the Boston bombers seriously enough, despite being warned by a foreign government of Tamerlan Tsarnaev’s potential radical links and his trip to Dagestan. However, American law enforcement agencies have a challenging task—especially compared to their UK counterparts—in the fact that the diversity of the terror threat in America is significantly higher, and therefore harder to locate and control.

For example, the US offenders we studied were from twenty-eight different nationalities and had a wide range of ancestries. Yet in the UK there were just fourteen different nationalities, with half of the offenses committed by those who have South-central Asian ancestry and over a quarter committed by Pakistani or British
Pakistani citizens.

Furthermore, US-based offenders lived in twenty-six separate states, with the most popular location, New York, home to fourteen percent. However, in the UK, forty-six percent lived in London, making the source of the threat far easier to predict. Britain has done much to shut down radical mosques, convict terrorists, and deport national-security threats in a bid to shift the “Londonistan” label the capital acquired in the 1990s. However, there appears to still be some way to go.

We also did a comparative analysis of a subject endlessly debated since the September 11th attacks—the extent to which poverty causes terrorism. While the UK has had occasional high-flyers—Bilal Abdulla, for example, the wealthy doctor convicted for his role in the failed terrorist attack in London’s West End and the attempted suicide attack on Glasgow airport in June 2007—the statistics show that American offenders are better integrated into society than their British counterparts. In the US, fifty-seven percent of individuals were working or in school at the time of the terror action. In the UK, it was just forty-four percent.

More than half (fifty-two percent) of individuals convicted in the US had, in fact, attended college. This included Ali al-Timimi, the ideologue at the head of a Virginia cell, who had a Ph.D. in computational biology, and Kifah Jayyousi, a battlefield jihadi who had a Ph.D. in civil engineering. By contrast, only thirty percent of UK offenders were known to have had a college education.

These statistics are worrying for the UK because they show how socioeconomically disadvantaged its Muslim population is in comparison to that of the US. Yet they should also concern Americans because they show that, while the US Muslim population is thriving in many ways and better assimilated than Europe’s, integration and success have not thwarted


In the US, twenty-three percent of individuals involved in acts of terror were converts to Islam, compared to only fifteen percent of offenders in the UK. The comparatively high numbers are in part the result of a high level of African American conversion, but there is also a higher proportion of whites who convert in the US (eight percent) than in the UK (three percent).

According to a 2007 report from the Pew Research Center, the US statistic is exactly in line with the proportion of converts to Islam residing in America. In comparison, approximately only four percent of the UK Muslim population are estimated to be converts, which means that the number of converts involved in terror is disproportionately high.

In both countries, converts have been on the front lines of terrorist plotting. In the US, this included Richard Reid, the 2001 “shoe bomber” (Reid was British but convicted in the US). In the UK, it included Nicky Reilly, who attempted to bomb a family restaurant in southwest England, only failing to cause a large loss of life when the bomb exploded prematurely in the restaurant’s toilet cubicle.

We also studied the seriousness of the terrorists’ preparations and found that almost half (forty-seven percent) of those in the US had received formal training, compared to just twenty-eight percent in the UK. American offenders were most likely to have received training prior to 9/11 in Taliban-controlled Afghanistan (sixty-eight percent of those who had trained anywhere did so there). In the UK, Pakistan was the most popular location for training (fifty-five percent), a predictable outcome given the large Pakistani community in Britain and the high volume of travel that occurs between the two countries. Only twenty-one percent of UK offenders had trained in Afghanistan, yet forty percent had received training within the UK itself. By contrast, only one percent of individuals in the US were trained on American soil.

US offenders were not only better trained but had more combat experience abroad (eighteen percent) compared to the UK (only four percent). More than half (fifty-seven percent) of individuals in the US were connected to banned terrorist groups, of which more than a third (thirty-eight percent) were connected to al-Qaeda. This is significantly higher than in the UK, where only thirty-four percent were connected to proscribed groups, and only thirteen percent were connected to al-Qaeda.


Not surprisingly, given the fact that offenders in the US were more likely to be terrorist-trained, battle-hardened, and connected to designated terrorist groups, the terror threat in America appears to be greater than that in the UK. Between 1997 and 2011, individuals who committed al-Qaeda–related offenses in the US killed a total of 3,223 people, of whom 2,996 died on 9/11 (the total figure does not include either the 2009 Fort Hood shooting, which the Obama administration has designated as “workplace related violence” and as of yet has not led to a conviction, or the Boston bombings). Prior to the recent murder of a British soldier, in the UK, fifty-two have died—all on 7/7/05. This number could have been much higher if the explosive devices in the backpacks of suicide bombers on the London transport system had not malfunctioned on July 21, 2005, and if police had not uncovered the 2006 terror plot to detonate homemade liquid bombs on multiple transatlantic flights. Overall, there have been ten terror plots in the US (as of 2011) that were either successful or resulted in convictions, or both; eight in the UK (as of 2010).

In America, a total of thirty-six individuals were involved in these plots; however, only seventeen percent were American citizens. In the UK, there were thirty-seven operatives involved in major plots, eighty-six percent of whom were British citizens. This is an important statistic because it shows clearly that while Americans have been as radicalized by al-Qaeda–inspired rhetoric, they have been less willing to kill than those who are British citizens. Furthermore, it proves that there is no clear link between terrorist training, combat experience (both of which were more common in the US), and the subsequent planning of large terrorist operations (which was, proportionally, more common in the UK). British terrorists were less likely to have received terrorist training, have combat experience, or have links to a foreign terrorist group. But they had more ambition to kill on a mass scale.

Offenders in the US lived in a wide range of states and were from a much broader variety of ethnic backgrounds. They were better educated and more economically successful than their British counterparts, as well as more likely to be hardened by training and experience. But US terrorist operations designed to kill on a large scale were still largely planned by foreigners.

So we know a good deal about candidates for terror in the US and UK. However, we do not know enough to create effective profiles (which are in any case politically problematic). The case of the Tsarnaev brothers shows the difficulty in predicting who will choose the path of terror. It is true that the Russian government warned about Tamerlan, the older brother. But the Russians have their own agenda about ethnic Chechens, none of whom have ever before been convicted in US courts for al-Qaeda–inspired offenses, let alone engaged in a terror attack.

But while few can claim to have seen the Boston bombing coming, the fact that it has now arrived shows that a new era of independent, smaller-scale terror entrepreneurship may have begun and that the US needs to protect itself from morphing terror threats without changing its character or national values. The UK has confronted this issue and become mired in a thorny liberty vs. security debate—not only over profiling but over indefinite detention, deportation, police stop-and-search powers, and antiterrorism legislation. This has been a painful process that the UK has got wrong more often than it has got it right. Perhaps the US can benefit from the British experience.

Robin Simcox and Emily Dyer are research fellows at the Henry Jackson Society in London.

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