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Terrorist groups use violence and threats of violence to publicise their causes and as a means to achieve their goals

Last Updated 06 January 2022

Terrorism is a major threat for businesses. Terrorist groups may seek to cause harm to the economy as a whole by attacking business premises or they may seek to attack specific businesses to advance their political agendas. The threat is not confined to the UK; companies that do business overseas may also be targeted. 

The most significant terrorist threat comes from Islamist terrorism with its ambitions to mount high impact attacks designed to result in mass casualties.

The current threat level from terrorism for the UK is SUBSTANTIAL, 'an attack is likely'.

Information on threat levels can be found on the Security Service (MI5) website and on GOV.UK.

Islamist Terrorism

The UK faces a serious and challenging threat from Islamist terrorism. 

The threat to the UK from Islamist terrorism has increased and diversified, driven by developments in Syria and Iraq. The situation there provided an environment for terrorist groups, including Daesh (also referred to as ISIL, ISIS or the Islamic State) and Al Qaida (AQ)-linked groups, to plan attacks against the West. The availability of a large pool of individuals who have travelled from the UK and Europe to Syria heightens this threat. As these individuals return to the UK, there is a risk that a terrorist group will have tasked them to conduct attacks, they will seek to conduct attacks on their own initiative, or radicalise other vulnerable individuals.

Any organisation could be directly or indirectly affected by Islamist Terrorism. Acts of terrorism vary in scale and purpose. Some aim merely to inflict superficial damage or cause public distress to draw attention to a particular cause. But others can be more violent and indiscriminate with far-reaching consequences. 

The threat of terrorism emanates from the Middle East, North, East and West Africa, South and South East Asia. Here, Daesh-linked groups, as well as AQ and their affiliates, continue to pose a significant threat to UK interests overseas.

The majority of terrorist attack plots in the UK have been planned by British residents. There are several thousand individuals in the UK who support violent extremism or are engaged in Islamist extremist activity. British nationals who have fought for extremist groups overseas continue to return to the UK, increasing the risk of terrorist attacks. Using skills acquired overseas, they may organise attacks under direction from outside the UK, or on their own initiative, or they might radicalise others to do so. While the majority of returnees will not mount attacks, the large numbers involved mean it is possible that at least some will attempt to do so.

Groups like Daesh make effective use of social media and modern communication methods to publicise and glamorise their acts and inspire others to undertake attacks in their home countries. Once inspired, an individual might decide to conduct a terrorist attack without any prior signs of radicalisation. Simple, self-organised attacks by UK-based Islamist extremists have increased and are inherently harder to detect than more complex and ambitious plots.

Not all Islamist extremist activity is direct attack planning. UK-based Islamist extremists are also supporting terrorism by:

  • Radicalising individuals to believe in the legitimacy of joining a terrorist network or carrying out a terrorist attack
  • Fundraising for terrorist networks, often through criminal activity such as diverting money donated to legitimate charities
  • Helping radicalised individuals to travel abroad to join a terrorist group and potentially receive training. Some of these individuals may receive direction to plan an attack back in the UK

Extreme Right-Wing Terrorism (ERWT)

Extreme Right-Wing terrorism (ERWT) is made up of various different ideological strands that include but are not limited to, white supremacy. It is not a new phenomenon; modern ERWT ideology began to manifest in Western Europe during the 1970's, based on Nazi concepts and influences from the USA.

Since the 1970's there have been a number of notable RWT attacks both in the UK and worldwide, including: the murder of Rt Hon Jo Cox MP in 2016, the Finsbury Park Mosque attack  in 2017, and the Christchurch Mosque Shootings in 2019.

In April 2020, the Security Services took over primacy of Extreme Right-Wing Terrorism investigations from the Police. 

Terrorist Methods

Terrorists can use many different methodologies in their attacks, including:


Improvised Explosive Devices (IEDs)

These can be delivered to their targets in vehicles, by post or by a person. Car bombs were frequently used by the IRA during the Troubles in Northern Ireland. Islamist terrorist groups often use suicide operatives in vehicles to improve the likelihood of the explosives detonating at the required moment, and suicide bombers also carry explosive devices into the vicinity of a target individual or location. Notable examples of this include the Manchester Arena attack in 2017 and the Easter Bombings in Sri Lanka in 2019.

Dissident republican groups in Northern Ireland continue to use a range of explosive devices, including under-vehicle devices, pipe bombs and postal explosive devices.


Shootings and close quarter attacks

Islamist terrorist groups have orchestrated a number of shootings and close quarter attacks targeting Westerners, in the Middle East, North Africa and Europe.

Notable examples include in June 2015 when Daesh claimed responsibility for an attack on the Port El-Kantoui tourist resort in Sousse, Tunisia which killed 38 people, including 30 British nationals and November 2015, when a terrorist cell conducted a series of coordinated attacks in Paris, using firearms and suicide bombs, killing 130 people and injuring 368 more. This was the most sophisticated western attack carried out by Daesh, involving at least nine operatives and using multiple weapons including automatic firearms and person-borne improvised explosive devices (PBIEDs). 

The use of firearms is also a popular methodology of extreme right-wing terrorists. Notable attacks using firearms include the Christchurch Mosque Shootings in March 2019. 

More recently the London Bridge and Westminster attacks in 2017 illustrate the threat from close quarter bladed weapon attacks.

Dissident republican groups have also used firearms in their attacks against the security forces in Northern Ireland. These have included the murders of Sappers Mark Quinsey and Patrick Azimkar outside Massereene Barracks in 2009, Constable Stephen Carroll in 2009, and prison officer David Black near Lurgan in November 2012.



Islamist groups in conflict zones around the world actively seek to kidnap Western nationals for financial and propaganda gain. In the latter half of 2014, Daesh released videos claiming to show the murders of, amongst others, UK nationals David Haines and Alan Henning. Through these, Daesh hoped to spread fear and attempted to show its strength over the West.

As well as in Syria and Iraq, the kidnap threat persists in Yemen and parts of the West, North and East Africa where Islamist groups are active.


Chemical, biological and radiological (CBR) devices

To date, no such attacks have taken place in the UK. Alternative methods of attack, such as explosive devices, are more reliable, safer and easier for terrorists to acquire or use. Nevertheless, it is possible that Al Qaida, Daesh, or other terrorist groups may seek to use chemical, biological or radiological material against the West.

In addition to physical attack methods, terrorists may also try to access information that may be of use to them. For example, they may try to radicalise an individual within an organisation who can provide "inside" information that helps to plan an attack.

More information about the terrorist threat can be found on the MI5 website and through our Recognising Terrorist Threats Guidance

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