Terrorists may use biological weapons. MI5 warns

A virus created in a garage

A few months earlier, a similar threat was highlighted by, among others, Stéphane Bancel, CEO of Moderna, a biotechnology company specialising in the development of modern medicines and vaccines (including those against COVID-19). In an interview in June 2026, he said: “I am very afraid of bioterrorism. Today, it is possible to develop a virus in a garage very cheaply and spread it across Europe. This applies to individuals and radical groups, but it can also be inspired (e.g. as part of hybrid warfare) by hostile states.”

The threat in this area is increasing not only due to the growing potential for perpetrators to use AI and other technological innovations, but also because of the strengthening links between terrorists, the special services of hostile states, and criminal groups. This dangerous triad takes on particular significance in current international circumstances, for instance, in the case of hybrid attacks and the state-sponsored terrorism often associated with them.

The end justifies the means

Terrorism is constantly evolving, and one of the most important manifestations of this is the search by terrorists for ever-newer forms of attack. These cover a wide spectrum of means, ranging from knives or firearms to speeding vehicles or bombings, and ending with attacks in cyberspace. A particularly surprising form of attack was, for example, the 2021 incident when a radicalised Danish Islamist killed five people and injured two others in Norway, primarily using a bow and arrow. Among the many diverse methods used by terrorists, however, the use of biological weapons deserves special attention.

Historical context

The use of biological weapons has occurred for centuries. One of the oldest cases was the use of a herd of rams infected with a dangerous substance by the Hittites in the 14th century BC, or the actions of Alexander the Great in the 4th century BC, whose troops abandoned the corpses of horses and soldiers who had died of infectious diseases during their retreat. Additionally, there were pandemics of various infectious diseases, such as the plague, which in the 14th century alone led to the death of 30% to 60% of the European population, according to various data.

Escalation of work on the use of biological weapons occurred in the 20th century. This was particularly the case during the Second World War and the Cold War, but also after it ended. For instance, during this period, the USSR alone achieved the capacity to produce 4.5 tonnes of anthrax annually. According to US intelligence data, 415 cases of terrorist attacks using chemical, biological, or fissile materials were recorded between 1900 and 1999. Threats of biological weapon use did not cease in the 21st century. This occurred, among other things, due to Islamists and Osama bin Laden’s declaration that the use of nuclear, chemical, or biological weapons is fully justified. In the aircraft that struck the WTC and the Pentagon on 11 September 2001, instructions were found for dispersing biological weapons using crop-duster aircraft. In the same year, letters containing anthrax were sent in the US, resulting in the infection of 22 people, five of whom died.

The contemporary threat

Biological weapons can be used not only by entities supporting or employing state-sponsored terrorism, including, for example, the special services of Russia or Iran, but also by terrorist or extremist organisations (such as ISIS, Al-Qaeda, Hamas, Hezbollah, and others), and even lone wolves. This is facilitated by the possibility of using AI, quantum computers, drones, or other technological innovations. A good example of this is the use of Starlink satellite internet by terrorist groups in West Africa or the use of AI by Houthi militants. They used the AI model Claude to design rockets and ballistic missiles, which was confirmed by the system’s manufacturer, Anthropic.

From the perspective of terrorists or other perpetrators, there are many arguments in favour of using biological weapons. The most important of these include: ease and low production costs, including through AI; the possibility of dispersal, for example, in aerosol form; inciting panic and intimidation; media publicity; high levels of infection and mortality; and often the lack of effective protection or treatment options. Hence the great concern among some states and medical communities regarding the situation that arose after the death in October 2026 of an employee at a Russian institute who broke a test tube containing the pneumonic plague pathogen. The mortality rate for pneumonic plague infection is 100% if untreated, and 30-50% with the use of appropriate antibiotics.

The threat of using biological weapons, even as an element of hybrid operations or for political, ideological, or propaganda purposes, is constantly rising. This is evidenced not only by subsequent warnings from experts but also by intelligence reports. The key question in all of this, however, is whether we will ignore another warning and to what extent we are effectively prepared for this threat.

It should be emphasised that, as reported by the World Health Organization (WHO), the problem of antibiotic resistance is also deepening, causing approximately 2 million deaths worldwide each year. In addition, there are 12 groups of dangerous bacteria for which there is currently no antibiotic. They cause the deaths of over 700,000 people annually. If new medicines are not discovered, this number could increase to as many as 10 million annually by 2050.

Prof. Sebastian Wojciechowski – Department of Strategic Studies and International Security at Adam Mickiewicz University (UAM). Chief Analyst at the Institute for Western Affairs. NATO DEEP eAcademy and OSCE security expert. Editor-in-Chief of “Strategic Review”. His recent publications include: Terrorism in Western and Central Europe: Good News is Bad News; NATO Summit in Ankara: Relief and a Sense of Unfulfilled Expectations; Europol and the New Terrorism Algorithm; and Forgotten victims of the 9/11 attacks.