The Nature of 21st Century Terrorism

Scene of terrorist attack
Terrorism has been around for centuries and is generally defined [1] in the United Kingdom as
“..the use or threat of action, both in and outside of the United Kingdom, designed to infuence any international government organisation or to intimidate the public and for the purpose of advancing a political, religious, racial or ideological cause”.

However, the global threat of modern terrorism really came to prominence following the suicide attack on the World Trade Centre by Al Qaeda on 11 September 2001. This mass attack killed 2996 people directly and led to the invasion of Iraq and the removal of the Saddam Hussein regime. Although suicide attacks weren’t a new concept, Al Qaeda learnt from other groups, such as Hezbollah, who were innovators of the modern phenomenon in the 1980s, and then took the concept to new levels. After peaking in 2015 and the decline of the ISIS entity, suicide attacks have fallen sharply in the Middle East and Africa (Pape, 2023) although terrorist attacks in all forms continue to occur both world-wide and in the United Kingdom.

Despite the numbers killed through terrorist attacks peaking in 2014, attacks and killings have remained relatively static in the last 5 years and, therefore, cannot be underestimated as an enduring threat to society and organisations. [3]

From the 1970s through to the end of the 20th century, the main perpetrators of terrorist acts in the United Kingdom were the Irish Republican Army and their primary modus operandi was the use of explosive devices placed in buildings and vehicles. These attacks reduced massively following the Northern Ireland Peace Agreement signed in 1998. A notable exception to this was the bombing of Pan Am Flight 103 over Lockerbie Scotland after taking off from Heathrow which claimed 270 lives. This incident was the deadliest terrorist attack on British soil and Colonel Gaddafi of Libya took responsibility for it. The motivation for this attack appears to be more likely to be to disrupt dialogue between the United States and the PLO rather than to be specifically against the British people. Notable recent events have often been perpetrated by Islamist extremists, such as the 2017 Manchester Arena bombings, the 2017 London Bridge van and knife attack and the specifically targeted stabbing of MP David Amess in 2021.

The terrorist threat in the United Kingdom is not solely related to Islamic extremists though. Official UK Government data shows a steady increase in the proportion of those imprisoned for terrorist offences having an extreme right-wing ideology. [4]

In 2014 approximately 3% of terrorist offence prisoners had an extreme right-wing ideology and this had risen to 26% by 2022

-Home Office, 2023  Statistics on the Operation of Police Powers under the Terrorism Act 2000.

Methodologies utilised by terrorist groups are varied and innovative often evolving as situational crime prevention displaces traditionally employed techniques. Explosive devices can be delivered to their targets in vehicles, by post or in person. Car bombs were frequently used by the IRA whereas Islamist groups have often made use of suicide operators in order to deliver the explosive devices to their target more effectively. It could be asserted that the rise in suicide operations from Islamic groups was a somewhat inevitable low-tech response to overwhelming military and economic power by the United States. As the US has adopted a less direct military approach in recent years, the number of suicide attacks has also diminished.

The nature of terrorist groups has also evolved moving from highly organized and secretive paramilitary groups, such as the IRA and the PLO, to ideologies exhorting a wider base of supporters to undertake unsophisticated attacks. Simple attack methodologies such as using a vehicle as a weapon require little in the way of resources or planning compared to smuggling weapons on board a plane to facilitate a hijacking. These groups have effectively utilized the internet to promote their cause and call to supporters to action.

Although terrorist bombings, shootings and kidnapping continue to take place, the threat is ever evolving as crime prevention makes traditional methods more difficult. For example, improved airport security and technology makes it harder to get explosive devices onto planes. The attackers of the World Trade Centers used the plane itself as the weapon and FAA rules at that time allowed them to board the plane carrying knives up to 4 inches in length. Air security rules developed yet again following the 9/11 attacks with far greater screening and restrictions on items that could be carried on to planes.

The rise in technology and the ever-increasing digital connectivity of the modern world does, however, also offer new opportunities to terrorists. Global Navigation Satellite Systems (GNSS) are integral to our daily lives not only in ensuring the global supply lines that underpin our economy but also supporting electricity supplies and our emergency services. GNSS signals can be vulnerable to spoofing and jamming using equipment that is both cheap and can be sourced from outlets as accessible as Amazon. Whilst the most basic GNSS jammers would be of little use to terrorists, it’s not a huge jump up to the level of equipment and expertise that could have significant impact on an organisation or society and, thus, could be seen as a high likelihood risk. Also given current political tensions between Russia and the West, GNSS attacks could be seen as viable grey zone operations both as a way of reducing the positional capabilities of weapons and unmanned arial vehicles as well as affecting critical national industry and the supply of goods.

On behalf of a government agency, we have recently been examining this threat to GNSS systems and the plans in place to mitigate against their disruption. Unlike simple access control measures to a threat, GNSS attacks can take many forms from attacks against the satellite itself down to jamming and spoofing on the ground. This entails a co-ordinated multi-agency response which adds to the difficulty of controlling such attacks and could well make such attacks even more attractive to hostile actors.

Whilst terrorists in the developing world may continue to employ traditional techniques with success, 21st Century terrorism is likely to continue to evolve as technology provides new ways for attacking powerful and advanced nations. The challenge for crisis managers will be to ensure that risk assessments and emergency response frameworks continue to adapt to respond to this.


[1]  UK. (n.d.). Terrorism Act 2000.
[2]  Pape, R. A. (2023). US restraint and the sharp decline of suicide attacks around the world. Chicago: Chicago Project on Security and Threats.
[3]  University of Maryland. (2022). Global Terrorism Database. National Consortium for the Study of Terrorism and Responses to Terrorism.
[4]  Home Office. (2023). Statistics on the Operation of Police Powers under the Terrorism Act 2000. Home Office.