Far-right radicalisation is increasingly turning into an intention to carry out terrorist attacks, MI5 director general Ken McCallum has warned. In his annual assessment of threats to the UK, delivered on 13 October 2026, he also highlighted Iran’s growing ambitions for hostile activity on British soil, including, according to the security service, against military sites.
The Guardian reports that the head of MI5, Britain’s domestic security service, described the shift from far-right radicalisation towards violence as the clearest trend in the service’s casework over the past year. His warning focused particularly on extremist anti-immigration and anti-Muslim attitudes increasingly becoming linked to the consideration of terrorist acts.
The Guardian identifies immigration centres and hotels housing asylum seekers among the potential targets being considered by extremists. This is an assessment of the threat observed by the security service, not a prediction that attacks on these locations will take place.
Iran and military sites in the threat assessment
Iran was another major theme of the speech. According to reports by the Guardian and Deutsche Welle, McCallum said Tehran was expanding its ambitions for hostile activity in the UK to harder targets, including military sites. He referred to Fairford and said it was not the only such case in the country, but did not name other sites or disclose details of the threats.
We covered the earlier case in “UK government links RAF Fairford incident to Iran. Tehran denies involvement”. The MI5 chief’s latest speech sets out a broader threat assessment; his comments about Iran’s intentions remain assessments by the British security service, rather than findings by a court.
McCallum said more than 50 people had been arrested in the UK over the past year in operations linked to Iran. That figure does not represent the number of people convicted or the number of confirmed attacks. He also identified a constraint on Tehran’s capabilities: the level of competence of the criminal intermediaries it uses to carry out activity abroad.
MI5 announces plans for an AI threat assessment centre
Artificial intelligence also featured in the annual assessment. According to the Guardian, McCallum warned about its use by terrorists and hostile states and announced plans to establish an AI threat assessment centre within MI5. This is an announcement of a new unit, not confirmation that it has begun operating.
The speech points to several parallel challenges for UK security: extremists moving from radical beliefs towards an intention to use violence, activity attributed to Iran by the security service, and risks associated with new technologies. McCallum’s most immediate warning, however, concerns a trend already visible in MI5’s work — the growing willingness of far-right extremists to consider terrorist attacks.
Sources
- https://www.theguardian.com/uk-news/2026/oct/13/rightwing-extremists-increasingly-likely-to-consider-terrorist-attacks-mi5-chief-says
- https://www.dw.com/en/iran-seeking-harder-targets-for-attacks-abroad-uk-warns/a-79654454?maca=en-rss-en-all-1573-rdf
- https://www.theguardian.com/politics/2026/oct/13/russia-brexit-eu-referendum-interference-mi5
