Does the US-Iran War Increase the Risk of Lone-Actor Terrorism in the UK?

• Lone-actor terrorism in the UK remains a persistent but relatively infrequent threat, with incidents such as theManchester Arena bombing illustrating its potential impact. Despite low attack numbers, disrupted plots and warnings from MI5 show that the risk environment remains active.
• The US–Israel–Iran conflict is unlikely to directly increase attacks, as the UK underKeir Starmer has avoided offensive involvement. However, it may still fuel polarization and grievance narratives that can contribute to radicalization.
• Overall, the risk is indirect and conditional, driven more by how the conflict is interpreted and amplified than by the conflict itself.

The long-lasting escalation at the Iran-Israel-US triangle has culminated in a full-scale war situation following US-Israeli attacks on Iran in late February 2026. In an era of digital media saturation, fragmented identities, and decentralized extremism, conflicts in one region can reshape domestic emotional climates in ways that influence political violence elsewhere. For the British population, one of the key questions to ask at this point is whether the US-Israel-Iran conflict may contribute to a heightened lone-actor terrorism risk environment in the UK. As a major ally of the US with a sizeable and diverse Muslim population, the UK may be exposed to intensified grievance narratives, identity polarization, and online radicalization dynamics, which are the factors consistently identified in research as enabling conditions for individual acts of extremist violence. This article examines the current state of lone-actor terrorism in the UK, evaluates potential risk factors, and assesses whether the risk environment is likely to change as a result of the conflict.

Current State of Lone-Actor Terrorism in the UK

A dataset of global Lone-Actor terrorism incidents, collated by the author and Mahmut Cengiz from open-source records, includes a total of 23 incidents in the UK between 2013 and 2025, representing approximately 2.4% of all incidents recorded globally. Across these incidents, 50 people were killed, and 1,198 were injured (excluding the perpetrators). It is important to note that 72% of fatalities and 96% of injuries stem from a single incident- the Manchester Arena Bombing in 2017.

Ideologically, 16 attacks were jihadist and 5 were linked to the far-right. With respect to targets, 11 attacks (48%) targeted civilians, 4 attacks targeted Muslim civilians, 3 attacks were made against security forces, 2 against government buildings and politicians each and 1 against a synagogue. In other words, 70% of attacks targeted non-state or non-governmental targets.

However, completed attacks alone do not capture the full threat landscape. In a major threat update, MI5 Director General Ken McCallum stated that “since 2017, MI5 and the police have together disrupted 43 late-stage attack plots.” Many of these plots involved individuals or very small groups radicalized online. More recent briefings indicate that 19 late-stage terrorist plots have been disrupted since 2020. Considered together, both realized and prevented attacks highlight the persistent threat posed by lone-actor or small-cell terrorism in the UK, even during periods of relatively low attack-completion frequency. As a matter of fact, thethreat levels in the UK have been fluctuating between “Severe” and “Substantial” since 2019, and the current level has been lowered from Severe to Substantial since September 2022. Therefore, it is important to analyze whether the ongoing war between the US-Israel bloc and Iran may increase the risk of lone-actor terrorism in the UK. This can be assessed through several potential risk factors: the UK’s stance in the conflict, religion-based grievance formation and polarization across communities, and Iran’s state-linked activities.

Political and Social Context

One of the major drivers of lone-actor terrorism is political grievance linked to Western foreign policy. The murder of David Amess in 2021 illustrates how such grievances can translate into violence in the UK. Therefore, the current stance of UK foreign policy in the ongoing war is an important indicator of potential terrorist risk.

First of all, there appears to be limited public support for active UK involvement alongside the US–Israeli bloc. In a YouGov pollconducted on 4–5 March 2026, 46% said the UK should take a purely defensive role, 26% preferred a limited retaliatory role, and only 8% wanted Britain to actively join US and Israeli attacks on Iran. Asked the same data a week later, the public had become 10 points more likely to oppose the conflict (59%), while support remained about steady at 25%. Similarly, in another survey by Survation on 5–6 March 2026, 49% said the UK should adopt a neutral position, 17% supported active UK involvement alongside the US and Israel, and 20% wanted Britain to oppose the conflict and work towards de-escalation. The same poll found 60% thought Parliament should approve any military action beforehand. It should also be noted that a considerable majority of those who are in favor of UK involvement in the conflict are affiliated with the Reform Party.

Both public opinion and government policy are aligned against military escalation. Prime Minister Keir Starmer has ruled out offensive involvement, stating: “We all remember the mistakes of Iraq, and we have learned those lessons.”

This alignment is significant, as lone-actor violence is often linked to perceptions of illegitimate state action. In this case, the absence of direct UK military engagement reduces the likelihood that grievances will escalate into violence. However, polarization remains a secondary concern. Support for intervention is concentrated within certain right-leaning segments, raising the possibility, though currently limited, of reciprocal radicalization. If the conflict becomes a domestic political fault line, it could create a climate in which both Islamist and far-right narratives reinforce one another.

Religious and Identity-Based Factors

A second risk factor is the religious dimension of the conflict. Beyond the issue of Palestine, Israel remains in conflict with several Muslim-majority countries in the Middle East. Following the 7 October Hamas attacks, Europol recorded a rise in jihadist incidents during the Gaza conflict, with most attacks carried out by lone individuals. The 2025 synagogue attack in Manchester can be seen as part of this pattern.

However, for many Sunni Muslim audiences and extremist milieus, Gaza generates far stronger emotional mobilization than tensions involving Iran. Sectarian divisions have long shaped perceptions of Iran as a Shia revolutionary state pursuing its own geopolitical agenda. As a result, Sunni emotional alignment with Iran is unlikely to match that seen in relation to Gaza, particularly given Iran’s involvement in conflicts affecting other Muslim countries.

On the other hand, the Sunni Muslims are still not supporting the US-Israeli attacks on Iran, and they believe that the attacks are part of Israel’s long-term interests of dominating the region, and Iran is merely one of those steps. In fact, a recent poll shows that while 14% of the general population believes Iran was not a significant threat prior to the US-Israel airstrikes, that figure rises to 45% among British Muslims. British Muslims are also more likely to attribute the strikes to attempts to gain control of oil supplies, at 40%, compared to 15% of the general population, and are far more likely to regard the strikes as definitively wrong, at 50% versus 17%. Meanwhile, antisemitic incidents remain at an exceptionally elevated level in the UK. CST recorded 3,700 antisemitic incidents in the UK in 2025, the second-highest annual total it has ever logged, up 4% on 2024. CST also said 1,766 incidents, or 48% of the 2025 total, showed explicitly anti-Zionist motivation alongside anti-Jewish targeting or language.

Taken together, conflicts framed as collective injustice against Muslims, particularly when associated with Israel, can contribute to the radicalization of a small number of individuals, especially when reinforced by existing grievances and polarizing narratives, and this risk factor seems to be the most powerful one in comparison to others.

State-Linked and External Threat Factors

A distinct and more direct risk factor lies in Iran’s history of overseas operations. MI5 and the Home Office have said the UK has responded to more than 20 Iran-backed plots since the start of 2022, involving potentially lethal threats to people in the UK, and the government has described the threat from Iran as growing and increasingly aggressive. Recent criminal cases and arrests linked to alleged Iranian surveillance in the UK reinforce that this is an active security concern.

In addition, two men were arrested following an arson attack targeting ambulances used by a Jewish charity in London in March. Although the Metropolitan Police initially indicated that the investigation was exploring links to an Islamist group with potential connections to Iran, following unsubstantiated claims of responsibility by Harakat Ashab al-Yamin al-Islamiya (The Islamic Movement of the People of the Right Hand), which had claimed responsibility for several arson attacks across Europe, the suspects were later released on bail, and no concrete links to the group have been established. The incident may instead reflect the anti-Israeli sentiment discussed in the previous section.

As a matter of fact, under the current circumstances, Iran-directed terrorist attacks in the UK, in the absence of direct British involvement in offensive operations against Iran, appear to be of relatively very low likelihood. Iran’s pattern of activity suggests a preference for targeted, deniable operations rather than indiscriminate attacks, particularly when escalation risks are high.

In conclusion, the escalation involving Iran does not necessarily lead to an increase in lone-actor terrorism in the UK. Such acts remain statistically infrequent and driven by complex personal pathways. However, the conflict might contribute to a broader environment marked by heightened geopolitical tension, polarized discourse, and ongoing online radicalization.

The most likely impact may be indirect. The war might increase grievance narratives, strengthen identity divisions, and supply ideological material that both Islamist and far-right groups could use. Meanwhile, the UK’s cautious policy approach lowers the chance of direct grievance mobilization.

Ultimately, the risk should be seen as conditional rather than guaranteed. The key factor is not the conflict itself, but how it is interpreted, amplified, and absorbed by domestic audiences. In this context, managing polarization, maintaining political legitimacy, and countering extremist narratives will be as crucial as traditional security measures in preventing any potential rise in lone-actor violence.