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 international terrorism with its ambitions to mount high impact attacks designed to result in mass casualties.

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

Northern Ireland-related terrorism also continues to pose a serious threat. Despite a peace process that has been active for several years, dissident Irish republican terrorists have continued to attack economic and political targets.

The current threat level for Northern Ireland-related terrorism in Northern Ireland is SEVERE.

The current threat level for Northern Ireland-related terrorism in Britain is MODERATE.

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

International Terrorism

The UK faces a serious and challenging threat from international terrorism. Since 2014, the threat has increased, and has been driven by developments in Syria and Iraq. The situation there is providing 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. DAESH has the ability to direct, enable and inspire attacks globally.

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. With the sophisticated, coordinated attacks in Paris and Brussels in November 2015 and March 2016 respectively, DAESH has proven its capability to direct large-scale attacks in Europe.

Despite the current main focus of terrorism originating from Syria and Iraq, the threat of terrorism also emanates from other parts of the Middle East and regions such as 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 this country 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 in the UK, 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 join them in Syria or 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.

The threat is constantly developing, presenting major challenges for the UK's intelligence agencies and the police.

Northern Ireland-related terrorism


The political and security situations in Northern Ireland have always been inextricably linked. Since the creation of Northern Ireland in 1921, the majority of its population has traditionally been regarded as unionist or loyalist, meaning that they wish to remain part of the United Kingdom. However, there has always been a significant minority of nationalists or republicans who support a united Ireland and regard themselves as Irish rather than British. Paramilitary organisations on both sides have carried out campaigns of terrorism, most notably during the Troubles; the three decades of conflict from the late 1960s onwards that resulted in over 3,000 deaths.

The nature of the terrorist threat in Northern Ireland has changed significantly in recent years. The Provisional Irish Republican Army (PIRA) and the main loyalist groups have ceased their terrorist campaigns and engaged with the political process. In April 1998 the Good Friday Agreement was signed, paving the way for a devolved Northern Ireland Executive based on power sharing between unionist and nationalist political parties. Although the Executive was suspended in 2002, it was successfully restored in May 2007 and has been in operation ever since.

Dissident republican groups

However, some dissident republican groups reject the political process and the institutions created by the Good Friday Agreement, and continue to carry out terrorist attacks. They seek to destabilise Northern Ireland through the tactical use of violence, targeting members of the Police Service of Northern Ireland (PSNI) and other security personnel as well as seeking to cause disruption and economic damage. They have very little public support.

There are three main dissident republican groups: the Continuity IRA (CIRA), the new IRA and Óglaigh na hÉireann (ONH). Since 2000 dissident republicans have mounted a steady number of attacks in Northern Ireland and between 2009 and 2012 they were responsible for the deaths of two PSNI officers, two British soldiers and a prison officer. Dissident republican attacks often involve collateral risk to members of the public, who are also regularly inconvenienced by the necessary police response to these and other incidents (such as hoaxes).

Aside from attacks against the security forces, dissident republicans also conduct punishment shootings and beatings against alleged criminals in an effort to enhance community support and undermine the PSNI. Many dissident republicans are also heavily involved in criminal activities for personal gain, including smuggling and extortion.

Terrorist Methods

Terrorists can use many different methods of attack. As well as using tried and tested methods, they are able to innovate, as demonstrated by attacks on New York on 11 September 2001. More recently in Paris, we have seen a complex plot involving multiple attackers and various weapons, all coordinated to occur simultaneously.

Example of physical methods of attack

  • Explosive devices

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.

International terrorist groups often use suicide operatives in vehicles to improve the likelihood of the explosives detonating at the required moment.

Suicide bombers also carry explosive devices into the vicinity of a target individual or location, as demonstrated on a number of occasions in attacks by AQ and DAESH on airliners.

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

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

Recent examples include in June 2015 whenDAESH claimed responsibility for an attack on the Port El-Kantoui tourist resort in Sousse, Tunisia which killed 38 people, including 30 British nationals.

More recently, in November 2015, 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).

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.

  • Kidnappings

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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