Islamist radicalisation: causes, warning signs and where to report

The short answer. Islamist radicalisation is the process by which a person comes to believe that Islamist violence, or a violent revolution for an Islamic state, is justified. Research finds no single profile and no conveyor belt from ordinary religious practice to terrorism. Social ties, grievance and a search for belonging and significance matter alongside ideology, and most people with extreme views never turn to violence.

Key facts #

• Europol reported 486 terrorism arrests in the EU in 2025, 347 of them for jihadism. Of those 347 suspects, 108 were aged 18 or younger (report of 13 July 2026).¹
• The Global Terrorism Index 2026 says youth and minors were 42 per cent of all terror-related investigations in Europe and North America in 2025, three times the 2021 share. The figure covers every ideology (March 2026).²
• Between January 2022 and March 2025, 44 minors were suspected of planning jihadist attacks in Europe. About 96.7 per cent of plots involving a minor were foiled, against 68.3 per cent of adult-only plots (June 2025).³
• England and Wales had 10,293 Prevent referrals in the year to September 2025. Where a concern type was recorded, 20 per cent were extreme right-wing, 8 per cent Islamist and 56 per cent had no identified ideology (6 August 2026).⁴
• ASIO's Director-General said on 19 February 2025: "the most likely perpetrator of a terrorist attack is a lone-actor, from a family previously unconnected to extremism."⁵

What does radicalisation mean? #

Radicalisation is the process of coming to support extreme ideas or violence ("radicalization" is the US spelling). The UK's ACT Early website calls it "the mental process" of being drawn down a dangerous path, and says it means "displaying extreme views in support of extreme ideologies or beliefs, terrorist groups and activities."⁸ A New South Wales coroner defined it in 2017 as the process in which a person "becomes increasingly committed to using violent methods" for extreme political, religious or ideological goals.⁹

Peter Neumann separates cognitive radicalisation, which is holding extremist beliefs, from behavioural radicalisation, which is using extremist means.¹⁰ UK guidance agrees: "Not all extremists become violent extremists, but some do."⁸

Islamist radicalisation is the case where the ideology is Islamism, the belief that Allah's law should govern the state. That is not the same as being devout. A 2008 MI5 study, reported by the Guardian, found that "a well-established religious identity actually protects against violent radicalisation."¹¹

How does Islamist radicalisation happen? #

There is no profile. The same MI5 study found that many terrorists "lack religious literacy" and that very few were raised in strongly religious homes.¹¹ A study of 119 lone attackers found "no uniform profile".¹² ACT Early lists bullying, peer pressure, low-level crime, struggling to fit in, a major life change and mental health problems as risk factors, and says a person's faith or ethnicity is not what makes an extremist.¹³

The group often comes first. The Shawcross review of Prevent, citing the researcher Marc Sageman, says real-world relations and family circles "can be crucial in moving some individuals towards radicalisation". A Department for Education study found that over half of the young people who travelled or tried to travel to Syria went with family or friends.¹⁴ Olivier Roy found that the typical European radical is a "second-generation immigrant or convert", often with petty-crime history, radicalised among "a group of friends or over the internet" rather than "in the context of a mosque".¹⁵

The quest for significance. Arie Kruglanski and colleagues describe three parts: a need for personal significance, an ideology that justifies violence, and a group that shares it.¹⁶

Why do people join ISIS? The Soufan Center estimated that over 40,000 foreigners from more than 110 countries joined Islamic State, about 4,000 of them from the EU (approx.).¹⁷ Leaked intake forms analysed by the Associated Press showed 70 per cent of recruits had only "basic" knowledge of Sharia. A former CIA officer concluded that "Religion is an afterthought."¹⁸ Roy draws a bigger lesson: terrorism arises not from "the radicalisation of Islam" but from "the Islamisation of radicalism". He adds that critics say he neglects political causes and the role of Salafism, which the guide to Salafism and Wahhabism covers.¹⁵

Ideas still matter. Shawcross says extremist ideologies "are advanced by movements and charismatic individuals", not by algorithms alone.¹⁴ The writers behind them, such as Sayyid Qutb, are in the guide to the Islamist ideologues.

What are the signs of radicalisation? #

ACT Early says: "More important than any one specific sign is the sense that something is not quite right with the person you're worried about." Every sign below can have an innocent cause.¹⁹

More behavioural signs, such as praise for attacks or plans to travel to a conflict zone, are in the Islamism guide. Dress, a beard or regular prayer are not warning signs, and the MI5 finding above suggests strong faith protects. ACT Early also stresses that "the vast majority" of people with mental health problems are not drawn into extremism.¹⁹

How does online radicalisation work? #

Europol's 2026 report says borderline content "typically served as an easy entry point". Users who showed interest could progress to networks sharing explicit terrorist material, usually moving "from mainstream platforms to more secure and private ones". Terrorist actors also copied game-design features such as rankings and challenges.¹ ASIO has called the internet "the world's single most potent and powerful incubator of extremism."⁷ The Islamic State guide covers its propaganda machine.

The evidence is less one-sided than the headlines. RAND Europe's study of 15 cases found the internet "is not a substitute for in-person meetings but, rather, complements in-person communication", though the sample was small and dates from 2013.²⁰ Shawcross warned in 2023 that online radicalisation "is currently a popular area of research and discussion, but that should not distract" from in-person radicalisation, which is "often more effective".¹⁴

Teenagers and terrorism: why are suspects getting younger? #

Youth is now the sharpest trend in the data:

• 108 of the 347 jihadist arrests in the EU in 2025 were of people aged 18 or younger.¹
• In Britain 46 people aged 17 and under were arrested for terrorism-related activity in the year to June 2026, the second highest since records began in 2001. This covers all ideologies (8 October 2026).²¹
• ASIO said minors were about two to three per cent of new counter-terrorism investigations a few years before 2022 and "closer to fifteen per cent" by then.⁷ In February 2025 it said "almost all" the potential terrorist matters investigated in 2024, of any ideology, "involved minors".⁵

The study of European plots finds that minors, the youngest aged 12, were "much less likely" than adults to have had contact with online recruiters (13.3 per cent against 37.2 per cent). About 70 per cent of the minors' cases were first found through open-source monitoring.³ Europol says young radicalised people "often displayed only a superficial understanding" of ideologies, and that personal grievances or mental health problems add to their vulnerability.¹

What is lone wolf terrorism? #

"Lone wolf" is the popular name for an attack by one person acting without orders from a terrorist group. Researchers prefer "lone actor". Europol says most attacks and plots in 2025 "involved lone actors or small, self-initiated cells", usually with simple weapons.¹

The label hides how connected such people are. In the 119-case study, "other people generally knew" about the offender's grievance, ideology or intent, events were "rarely sudden and impulsive", and "many but not all" were socially isolated.¹² Mental illness is more common among lone actors than group members (odds 13.49 times higher),²² but for Islamic State-linked Western attackers the authors found 27.6 per cent with a history of psychological instability, close to the general population, and called the result "extremely preliminary".²³

Lone wolf terrorism examples.

• Lindt Café siege, Sydney, December 2014. Man Haron Monis took hostages, and two died. The coroner found "no evidence" of direct or indirect contact with Islamic State, and left open whether it motivated him, but ruled the siege a terrorist incident.⁹
• Westminster, 22 March 2017. Khalid Masood drove into pedestrians and killed PC Keith Palmer; five people and the attacker died. David Anderson's review says Masood "appears to have acted alone", though he had once been a peripheral figure in an MI5 investigation.²⁴
• Fishmongers' Hall, London, 29 November 2019. Usman Khan, jailed in 2012 for preparing terrorism and released as a high-risk Category A prisoner in late 2018, killed Saskia Jones and Jack Merritt before police shot him.²⁵

Each attacker acted alone on the day yet had earlier contact with the authorities. More cases are in the guides to terrorist attacks in Europe, Islamist terrorism in the UK, Islamism in Australia and Islamist terrorism in the US.

Where do I report a concern about radicalisation? #

• United Kingdom. In an emergency call 999. To talk through a concern, call the police hotline on 0800 789 321 or report online at gov.uk/ACT. Your call will not be recorded, you need not give your name, and "it is ok if you are not sure."²⁶ Families can call the ACT Early Support Line on 0800 011 3764, open 24 hours.¹⁹
• Australia. For an immediate threat, call the police (000). For anything that concerns you, call the National Security Hotline on 1800 123 400, open 24 hours a day, seven days a week.⁶²⁷
• United States. Submit a tip at tips.fbi.gov, where tips can be anonymous, or call 1-800-CALL-FBI (225-5324). In an emergency contact 911 or local police.²⁸²⁹

A Prevent referral leads to support, not a charge. A multi-agency panel decides whether support is needed, and a case is "adopted" only where the person gives consent.⁴ The guide to countering extremism looks at whether such programmes work.

What cuts the other way? #

• Most people with extreme views never act. Muslims as a group are not the threat. In the US, Charles Kurzman counted Muslim-Americans as the source of the first tip for 52 of 140 Muslim-American terrorism suspects whose tip could be identified (as of 2012), though he did not separate community leaders from other members.³⁰
• It is not only Islamist. Extreme right-wing referrals outnumber Islamist ones in the Prevent figures above.⁴ ASIO's June 2026 speech cited cases inspired by neo-Nazi, extreme right-wing and extreme left-wing views, and ASIO said in 2025 that fewer than half of matters were religiously motivated.⁶⁵ Yet Europol found jihadist attacks the deadliest in the EU in 2025, with five of the six deaths.¹
• Signs overlap with growing up. ACT Early says teenagers who push boundaries and become more secretive are, "in most cases", behaving normally.¹³
• The evidence is thin. Many studies, such as RAND's, rest on small samples of people who were caught.²⁰

Questions people ask #

What is radicalisation? #

Radicalisation is the process by which a person comes to support extreme beliefs and, in some cases, violence to defend them. In the UK it is described as a mental process in which someone is drawn towards extreme ideologies or terrorist groups. "Radicalization" is the US spelling. Not everyone with extreme views becomes violent, and being devout is not the same as being radicalised.

What are the signs of radicalisation? #

There is no single sign. UK guidance says to look for a combination that is growing: a person who talks as if reading someone else's script, cuts off old friends and family, becomes secretive about online contacts, shares hateful content, or seems angry and rigid in their views. Each can have an innocent cause, so trust your instincts and ask for advice early.

Why do people join ISIS? #

Researchers find a mix of reasons rather than one cause. Belonging, a search for significance or purpose, adventure, grievance and friends who are already involved appear repeatedly. Leaked Islamic State intake forms showed most recruits had only basic knowledge of Sharia, so religious learning was rarely the driver. Preachers and propaganda then supply a doctrine that justifies violence.

What is lone wolf terrorism? #

Lone wolf terrorism means an attack by one person acting without orders from a terrorist group. Researchers prefer the term lone actor, because most such attackers have had contact with others and often told them about their views beforehand. Examples include the Lindt Café siege in Sydney in 2014, the Westminster attack in 2017 and the Fishmongers' Hall attack in 2019.

How does online radicalisation happen? #

It usually starts with ordinary-looking or borderline content that acts as an easy entry point. Users who show interest are invited into closed groups on private or encrypted apps, where extreme views are shared and normalised. Research finds the internet usually complements real-world contact rather than replacing it, and it can speed the process up, in some cases to a few weeks.

Where do I report someone who may be radicalised? #

In the UK call 999 in an emergency, or the police hotline on 0800 789 321, or report online at gov.uk/ACT. Worried families can call ACT Early on 0800 011 3764. In Australia call the National Security Hotline on 1800 123 400. In the United States use tips.fbi.gov or call 1-800-CALL-FBI. You do not need proof, only a concern.

Related guides #

• Counter-extremism: what works and what fails in stopping radicalisation.
• Islamism explained: what an Islamist is, and the warning signs in more detail.
• Salafism and Wahhabism: the creed, the three strands and the jihadist split.
• Islamist ideologues: Qutb, Maududi, al-Banna and the ideas behind the movement.
• Islamic State: its propaganda, recruitment and decline.
• Terrorist attacks in Europe: the attacks, year by year.

Cite as: The Analyst, "Islamist radicalisation: causes, signs and where to report", Fighting Islamists, updated 13 October 2026. https://fightingislamists.com/radicalisation.html

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