Keep Calm and Carry On: The Terrorist Threat in the United Kingdom

CSIS Briefs


The Issue

On August 14, Salih Khater ploughed his Ford Fiesta into pedestrians and cyclists near the Houses of Parliament in downtown London, wounding several of them. The tactic—a vehicle attack—fits a growing pattern of simple attacks in Europe and the United States using cars, trucks, knives, and easily-accessible items. Perhaps the most notable lesson from the attack, however, was local resilience. Londoners were hardly bothered, living up to the UK government’s World War II campaign to “Keep Calm and Carry On.”

The August 14 attack in London is the latest reminder that terrorism persists in the West more than a decade and a half after September 11, 2001. The United States continues to face a threat from right-wing, left-wing, and Islamic extremists, despite comments from some U.S. policymakers that terrorist groups have been defeated. Perhaps the most significant lesson from the London attack, however, is the resilience of the British public. They kept calm and carried on.

The attacker was Salih Khater, a UK citizen from Birmingham who was in his late twenties. He drove a silver Ford Fiesta into a crowd of pedestrians and cyclists in London and then crashed it into a security barrier outside the Houses of Parliament. Eyewitness accounts were chilling. “I heard lots of screams and turned round,” remarked Barry Williams. “The car went on to the wrong side of the road to where cyclists were waiting at lights and ploughed into them.”1 The tactic—a vehicle used as a weapon—is all too familiar. Terrorists in the West have increasingly resorted to simple tactics, such as vehicles and knives, to kill civilians.

Compared to previous incidents in the United Kingdom, Salih Khater’s August 14 attack was second-rate. He had been meandering around London for several hours, which suggests that the incident was not carefully planned. His tiny Ford Fiesta was no match for the barriers around the Houses of Parliament that are designed to stop attacks from 18-wheelers. And Khater failed to kill anyone, though he did injure several people.

UK security agencies have conditioned their public to be prepared for plots and attacks. The United Kingdom’s recently-published counterterrorism strategy, CONTEST, argues that the country faces a significant, multidimensional threat from terrorists. According to data from the European Union Agency for Law Enforcement Cooperation, there were more failed, foiled, and completed attacks in the United Kingdom than anywhere else in the European Union in 2017.2 There were also more terrorist-related arrests in the UK in 2017 than in any previous year since 2001.3 Between December 2013 and May 2018, British intelligence and law enforcement agencies thwarted 25 plots from extreme Islamic groups.4 Most of these plots were inspired by the Islamic State and its ideology, rather than directed by Islamic State operatives.5

On March 22, 2017, for example, British-born Khalid Masood drove a sports utility vehicle into pedestrians crossing Westminster Bridge in London, killing three people. Masood then took two carving knives out of his vehicle and stabbed police officer Keith Palmer, killing him outside of Parliament. On May 22, 2017, Salman Abedi detonated an improvised explosive device in the foyer of Manchester Arena, killing 22 people; 10 of them were under 20 years old. On June 3, 2017, three men—Khuram Butt, Rachid Redouane, and Youssef Zaghba—drove a van into London Bridge, killing two people. They then jumped out of the van and killed six more people using large knives. On September 15, 2017, an 18-year old Iraqi asylum seeker named Ahmed Hassan detonated a bomb using triacetone triperoxide (TATP) on a District line train at Parsons Green Underground station in London. Thirty people were treated for burn and other injuries.6

Right-wing terrorism has also been on the rise in the United Kingdom. On June 19, 2017, Darren Osborne, a 47-year old British man, drove a van into Muslim worshippers near Finsbury Park Mosque, London, killing one person.7 On June 23, 2017, Marek Zakrocki, a known supporter of the far-right party Britain First, drove a vehicle into an Indian restaurant in London, injuring several people. He was armed with a kitchen knife and a baton-torch, and he told police: “I’m going to kill a Muslim. I’m doing this for Britain. This is the way I am going to help the country. You people can’t do anything. I am going to do it my way because that is what I think is right.”8

While there have been relatively few terrorist attacks in the United States recently, the United Kingdom—and Europe more broadly—have faced a more severe threat. The number of jihadist-related terrorist attacks in the European Union peaked in 2017 with 33 failed, foiled, and completed attacks. This number was up from 13 in 2016, 17 in 2015, and 2 in 2014. The geographic distribution of attacks also expanded. European Union countries experiencing jihadist-related terrorism now includes such countries as the United Kingdom, France, Germany, Spain, Belgium, Sweden, Denmark, and Finland.

Figure 1: Jihadist-Related Attacks in the European Union, 2014-20179

As the August 14 London attack highlights, terrorist tactics in the United Kingdom have also become increasingly simple. Between 1998 and 2015, nearly three quarters of terrorist attacks in the United Kingdom were crude bombings, followed by smaller percentages of stabbings (15 percent), vehicle attacks (12 percent), and other types of attacks. But the percentage of stabbings and vehicle attacks increased over time.10 Strong gun laws and aggressive law enforcement in the United Kingdom mean that bladed weapons like knives have been more common than guns. Vehicles have also become more common since a truck killed 86 people in Nice, France in July 2016. In several cases—including the 2017 Westminster Bridge and London Bridge attacks—both vehicles and bladed weapons were used, much like the May 2013 attack against British Army soldier Lee Rigby in southeast London.11

Simple attacks have become de rigueur among some terrorists in Europe. As Figure 2 highlights, vehicles were used as a weapon in 11 percent of attacks in 2017 by Islamic extremists, though only 3 percent by all terrorists (which include extreme right-wing, left-wing, religious, and nationalist violence). Most other weapon types were also relatively easy to acquire, such as a melee (a weapon used in direct hand-to-hand combat like a knife, sword, or axe), incendiary devices, and firearms. In addition to the July 2016 Nice attack, terrorists used vehicles to kill civilians outside of the United Kingdom in December 2016 in Berlin, April 2017 in Stockholm, June 2017 in Paris, August 2017 again in Paris, and August 2017 in Barcelona—among others. There have also been a handful of vehicle attacks in the United States, including the October 2017 attack along the Hudson River Park’s bike path in New York City and the August 2017 attack at the Unite the Right rally in Charlottesville, Virginia.

Figure 2: Terrorist Attacks in Europe by Weapon Type, 201712

The data suggest, however, that these simple attacks generally don’t kill large numbers of people. Salih Khater’s August 14 attack killed no one.13 Instead, complex attacks that involve multiple perpetrators armed with improvised explosive devices and guns are likely to be more lethal. For example, the July 2005 attack in London killed 56 people, and the November 2015 attack in Paris killed 137 people.

In addition to serving as a reminder that the terrorist threat persists, the UK experience offers an equally important lesson for the United States: the UK public and government officials have exhibited impressive resiliency in the face of terrorism. Part of this resiliency comes from the United Kingdom’s decades-long experience with terrorism, dating back to the struggle with the Irish Republican Army. In a May 2018 speech in Berlin, MI5 Director General Andrew Parker remarked that “Europe faces an intense, unrelenting and multidimensional international terrorist threat.” But he was also sanguine “because of the strength and resilience of our democratic systems” and “the resilience of our societies and the support of the public.”14

In response to the August 14 London attack, the UK government held an emergency meeting of its Cobra committee and the prime minister, Theresa May, thanked emergency responders for their “formidable courage.” She also urged the public to “carry on as normal.”15 UK citizens in London were hardly bothered, living up to the British government’s World War II campaign to “Keep Calm and Carry On.” The United Kingdom’s resiliency is a good reminder for the U.S. public when the next attack happens in the United States.

Seth G. Jones holds the Harold Brown Chair, is director of the Transnational Threats Project, and is a senior adviser to the International Security Program at the Center for Strategic and International Studies in Washington, D.C. He is the author, most recently, of “A Covert Action: Reagan, the CIA, and the Cold War Struggle in Poland” (W.W. Norton).

The author gives special thanks to Max Markusen, Danika Newlee, and Clayton Sharb for their comments, assistance in pulling data, and creation of Figures 1 and 2.

CSIS Briefs are produced by the Center for Strategic and International Studies (CSIS), a private, tax-exempt institution focusing on international public policy issues. Its research is nonpartisan and nonproprietary. CSIS does not take specific policy positions. Accordingly, all views, positions, and conclusions expressed in this publication should be understood to be solely those of the author(s).

© 2018 by the Center for Strategic and International Studies. All rights reserved.

[1] “Westminster Car Crash: Man Arrested on Suspicion of Terror Offences,” BBC, August 14, 2018, available at:
[2] Europol, European Union Terrorism Situation and Trend Report (The Hague: European Union Agency for Law Enforcement Cooperation, 2018), p. 54.
[3] Grahame Allen and Noel Dempsey, Terrorism in Great Britain: The Statistics (London: House of Commons, June 7, 2018), p. 14.
[4] Andrew Parker, Director General of the Security Service, “Speech to the BfV Symposium in Berlin,” May 14, 2018, available at:
[5] Peter Nesser, Anne Stenersen, and Emelie Oftedal, “Jihadi Terrorism in Europe: The IS-Effect,” Perspectives on Terrorism, Vol. 10, No. 6, December 2016, pp. 3-24.
[6] David Anderson, “Attacks in London and Manchester: Independent Assessment of MI5 and Police Internal Reviews,” December 2017, available at:
[7] Crown Prosecution Service, “Man Given Life for Finsbury Park Terror Attack,” February 1, 2018, available at:
[8] Metropolitan Police, “Man Convicted After Telling Police He Was Going to ‘Kill a Muslim,” December 4, 2017, available at:
[9] The data come from the Global Terrorism Database at the University of Maryland, available at:
[10] Hannah Stuart, Islamist Terrorism: Analysis of Offences and Attacks in the UK (1998-2015) (London: Henry Jackson Society, 2017), p. 975.
[11] Anderson, “Attacks in London and Manchester.”
[12] The data come from the Global Terrorism Database at the University of Maryland, available at:
[13] The January 2017 Nice attack, which killed 87 people, was an exception, in part since it involved a 19-ton rental truck.
[14] Parker, “Speech to BfV Symposium.”
[15] “Westminster Car Crash: Man Arrested on Suspicion of Terror Offences,” BBC, August 14, 2018, available at:


Seth G. Jones
Senior Vice President; Harold Brown Chair; and Director, International Security Program