ProtectUK publication date
The threat of a terrorist attack by firearm in the UK is not likely, but it is important to understand how the threat of firearms may impact you or your business.

Headline Assessment

  • Terrorist attacks in the UK using firearms are extremely rare. In the last twenty years there has only been one occasion where a firearm has been discharged in a terrorist attack on the UK mainland.

  • Although there is a criminal market for firearms in the UK it is likely that access to this market for terrorist attack planners is limited.

  • Homemade manufacture of firearms provides individuals with the opportunity to acquire a firearm without needing to utilise a criminal contact or risk detection through importation of an original lethal purpose (OLP) firearm.

  • Hybrid 3D printed firearm models require a lower level of skill despite the increasing complexity and capability of the designs, making them more appealing for individuals without criminal contacts.

  • The availability of ammunition is a barrier to successful terrorist acquisition and use of firearms.

  • Terrorist acquisition of automatic firearms would likely require access to organised crime groups.


Firearms in the UK

According to the Office of National Statistics there were 156,033 firearm certificates and 548,521 shotgun certificates on issue in England and Wales as of 31 March 2021. Whilst the numbers appear high, the UK has one of the lowest rates of legally held firearms per head of population in the western world.

Gun crime in the UK is one of the lowest in the world. One league table of worldwide gun-related homicides by country places the UK near the bottom with 0.06 deaths per 100k of population (compared with 4.46 in the US and 66.64 in Honduras). Globally, shooting was the most common type of terrorist attack in 2020.

The illicit firearms market in the UK is used by criminal networks and urban street gangs. The market is supply driven, meaning the variety of firearms available is limited. It is difficult to estimate how many illegal firearms are held in the UK and estimates have varied from several hundred thousand to over a million. The illicit firearms market could supply terrorist acquisition, however, this would rely on the use of a criminal contact. In some cases criminal suppliers of firearms may be unwilling to supply terrorists due to increased scrutiny from law enforcement, the subsequent impact this would have on their criminal activity and potential sentences. The possibility of their communities being targeted in a terrorist attack is also likely to act as a deterrent for firearms suppliers who have been approached by terrorist attack planners.


Terrorist use of Firearms in the UK

UK terrorist attacks using firearms are extremely rare. In the last twenty years there has only been one occasion where a firearm has been discharged in a terrorist attack on the UK mainland. This was in 2016, when a white nationalist, shot and stabbed the MP Jo outside a surgery in Birstall, West Yorkshire.


How can the UK markets be exploited for terrorist acquisition?

Current regulations limit the types of firearm available within the UK. Firearms that can be legally owned on individual licence are limited to certain types of shotgun and rifles, however these types of firearms do not hold large amounts of ammunition or have the rapid rate of fire capable with automatic firearms. These limitations reduce their threat in being used to cause mass casualties in a terrorist attack. The criminal market can acquire shotguns and rifles through theft from licence holders, however licence conditions require their secure storage. Subsequent terrorist acquisition could occur from the criminal market, but only where criminal contacts were available. It is highly unlikely that someone known to law enforcement for terrorism related offences would be able to acquire a firearm legally.

Although production of firearms is regulated, the criminal market for firearms is also supplied through domestic manufacture. This could provide a means of acquiring a firearm without criminal contact, or risking detection through illegal importation of a commercially produced firearm. Homemade firearms can be broken down into:

  • Conversion of blank firers

  • Basic metal work

  • Complex metal work

  • 3D printing

Types of legally available firearms designed to discharge blank rounds can be converted to fire bulleted ammunition. This conversion could occur within the UK, or abroad prior to illegal importation. These types of firearms do have gunpowder but do not use bullets and are typically starter pistols and prop guns. Blank firers would require some kind of criminal contact particularly for professionally converted models, or a level of skill in order for them to be functional once converted. Both of these may reduce their appeal for individuals attempting to acquire a firearm for a terrorist attack.

Basic metal work firearms can be made using commercially available metal and require a lower level of skill to produce, which results in an inaccurate firearm with a slow rate of fire but could be fatal when used in close range. This is likely to be less attractive to individuals who are looking to conduct a mass casualty terrorist attack.

Designs for complex metal firearms, constructed with domestic tools, are available and possible models could include semi-automatic designs with capabilities similar to commercial firearms. However, the skill level required to produce these firearms is likely to be prohibitive to most individuals. There are designs that have been shared online and are known to have been used in the terrorist attack in Halle, Germany.

Until recently 3D printing for firearms has involved designs which are mostly plastic, resulting in fragile and unreliable firearms. This has limited their criminal and terrorist use. Initially law enforcement concern regarding 3D printing for firearms focused on their detectability at borders, the risk of them being illegally brought on to planes and used in a terrorist attack on board. More recently global opponents to gun control have accelerated the number and complexity of designs for hybrid 3D printed firearms, which are a combination of 3D printed plastic and metal work. The only known 3D printed firearm involved in an actual attack was a hybrid design manufactured by the terrorist attacker in Halle, Germany. However this firearm was not discharged, with the fatal shots fired using a complex metal work design. Metal parts required in hybrid designs improve the viability and reliability, as printing pressure bearing parts out of plastic is not always viable. This also improves law enforcement opportunities for detection at borders. These types of hybrid models require a lower level of skill and may be an attractive route for terrorists to acquire a firearm. As the anti-gun control community continue to further develop models as a means to oppose firearms legislation, the complexity and capability of these firearms may increase, whilst becoming more achievable to an unskilled manufacturer.

Ammunition is a pivotal barrier for successful terrorist acquisition of firearms, particularly as the UK is facing an ammunition shortage. Commercial ammunition will need a criminal contact, which negates having to make a firearm in the first place. As with complex and basic metal work in the production of a firearm there are alternative methods to manufacture ammunition, with similar differences in the quality of the item produced. Simple methods to produce ammunition exist, but produce low powered and inaccurate rounds. More complex methods are available to produce rounds similar to commercial ammunition, but the skills and tools required may be prohibitive.


Future threat from terrorist use of Firearms

A reduction in the severity of firearms regulations in the UK is not likely, however new models of blank firers could appear for sale in the UK which can be temporarily exploited for criminal purposes. Response from law enforcement has previously resulted in such items becoming restricted, or removed from sale.

The global anti-gun control community are promoting and encouraging more advanced and complex models of hybrid 3D printed firearms. It is a realistic possibility this will result in higher-capacity, lethal weapons becoming available through more unskilled production. However, successful terrorist use of these types of firearms still relies on the availability of ammunition.


What does this mean for business and the public?

A terrorist enabled firearms attack will cause widespread concern for the public due to the increased likelihood of an attack resulting in higher number of fatalities, conducted with a commodity controlled under UK law. If a targeted attack is carried out, this would lead to wider fears within the targeted community. However, such an attack is not likely to have a long term commercial impact or cause sustained disruption to daily life.

Continued joint work from public firearms groups and law enforcement is necessary to ensure the reduced availability of firearms, in the UK. Additionally revised guidelines have been published which may see further amendments following the inquiry into firearms legislation and licensing in the UK as a result of the attack in Plymouth

Probability and Likelihood in Intelligence Assessments

When describing threats in intelligence assessments, Counter Terrorism Policing utilises the Probabilistic Yardstick.

The Probabilistic Yardstick is a tool created by the Professional Head of Intelligence Analysis (PHIA), in the UK government, to standardise the way in which we describe probability in intelligence assessments. For example, if we use the term ‘likely’ what we mean is ‘a 55-75% chance’.

Use the scale below as a reference when reading ProtectUK Insights.

Probabilistic Yardstick

Threat analysis
Attack Methodology