MI5 has warned of the increased extreme right wing threat (Image: Getty)
Britain’s migrant crisis is making a terror attack more likely, the head of MI5 has warned. Sir Ken McCallum admitted intelligence officers have seen an increase in “anti-immigration and anti-Muslim” grievances “tipping into terrorist intent”.
He said MI5 has foiled plots to attack mosques and “venues connected to immigration and asylum”. Sir Ken’s intervention will prompt renewed focus on the disastrous impact of the failure to control Britain’s borders.
The Security Service chief said: “For the first time in almost five years, JTAC recently returned the UK terrorism threat level to SEVERE, meaning an attack is highly likely.
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“While the threat level change reflects the whole of the terrorist threat, the recent increase was driven in significant part by Extreme Right-Wing Terrorism.
“This is a complex landscape, with many subcultures.
“Over the last year, the most marked trend has been an increase in cases where extremists of anti-immigration and anti-Muslim grievance are tipping into terrorist intent; we’ve dealt, for example, with would-be terrorists aspiring to attack mosques and venues connected to immigration and asylum.”
MI5, Sir Ken said, is still foiling Islamist attempts “to carry out mass casualty attacks in the UK”.
More extremists are holding anti-immigrant views (Image: Getty)
He said: “Determined efforts have degraded the leadership of Islamic State, but Al-Qaeda and Islamic State continue to direct and inspire attacks.
“Three Islamist extremists were convicted in February for planning to use automatic weapons against the Jewish community in Manchester.”
But Britain’s top intelligence officer warned extreme right-wing terrorism” continues to “skew” young people radicalised by online propaganda.
He said: “A few months ago, MI5 was investigating a radicalised extreme right-wing 13-year-old here in the UK.
“Believe me, we wish we didn’t have to. But that investigation generated insight that enabled one of our international partners to prevent a lethal attack on their soil.”
He also mentioned the case of a 16-year-old from Inverclyde who was jailed for 10 years for plotting to attack an Islamic centre.
Official figures show that in 2025, 39 people aged 17 and under were arrested in connection with counter terrorism investigations, and 40 the previous year.
Former MI6 chief Sir Richard Moore on Monday warned migration is one of the issues Russia wants to exploit in an information war.
And Sir Ken warned Britain’s adversaries are trying to “manipulate how we feel”.
He said: “In the era we’re now in, the cohesion and confidence of our communities has become a national security front line.
“Those who mean us harm are trying – often with a helping hand from polarising algorithms – to divide our communities and turn us against one another.
“The sharpest form this takes is lethal violence. We were all horrified by the murder of Ann Widdecombe in July.
“Sadly, the case is part of a concerning trend of violence targeted at political figures, religious or community groups and more.”
Sir Ken added: “Authoritarian regimes also try to impose their will. They have forever sought to silence dissenting voices among their people, including in the UK.
“But these days they also invest in trying to distort and divide our society, weaponising whatever frictions they notice.”
Reform UK leader Nigel Farage on Monday warned Labour is letting terrorists, serious criminals and dangerous sex offenders cross the Channel in small boats.
Mr Farage vowed to regain control of the borders by shutting the asylum system for five years.
He said: “What is happening is a national security emergency. We are letting terrorists come into the country.
“We are letting serious criminals come into the country. We’re letting dangerous sex offenders into the country. And our primary purpose is to stop that from happening.
“We have got to be very, very careful about not letting any more of our enemies into the country.”
MI5 Chief Issues Urgent Warning Over Terror Threat Linked to UK’s Migrant Crisis
Britain has been placed on heightened alert following a stark warning from MI5 chief Sir Ken McCallum about the evolving terrorist threat facing the country. In his annual security update on October 13, 2026, the head of Britain’s domestic intelligence service highlighted a worrying increase in cases where extreme anti-immigration and anti-Muslim grievances have developed into an intention to carry out terrorist attacks. His remarks have reignited the national debate over immigration, border security, radicalisation and the government’s responsibility to protect the public. <Cite refs={[“turn104556search0″,”turn758206view1”]}/>
The warning comes at a time when migration remains one of the most politically divisive issues in the United Kingdom. Accommodation for asylum seekers, small-boat crossings across the English Channel and the management of Britain’s borders have generated intense public debate. Political parties have repeatedly clashed over whether existing policies are sufficiently effective and what further measures might be required.
However, McCallum’s assessment contains an important distinction. His warning was not simply about immigration itself. Rather, he highlighted how extremist beliefs, online radicalisation and hostility towards particular communities can develop into plans for violence. The intelligence chief also emphasised that Islamist terrorism continues to pose a serious danger.
His message presents a significant challenge for Britain’s political leaders: how can the government address legitimate public concerns about immigration while preventing extremist movements from exploiting those concerns to encourage violence?
MI5 Warns of a Changing Terrorist Threat
During his annual speech, McCallum described Britain as entering a new era of national security. He explained that the threats confronting the country have become more varied and complicated, requiring intelligence agencies to adapt their methods and priorities.
One of the most concerning developments identified by MI5 was the increasing number of cases in which extreme right-wing individuals moved from anti-immigration or anti-Muslim hostility towards an intention to commit terrorist acts.
According to the intelligence chief, this was the most pronounced trend in the agency’s recent caseload. Investigations have included individuals who aspired to attack mosques and locations associated with immigration and asylum accommodation. <Cite refs={[“turn758206view1″,”turn104556search2”]}/>
These cases demonstrate why intelligence agencies pay close attention to behaviour and the development of violent intentions rather than simply monitoring political opinions.
Holding a critical view of immigration policy does not, by itself, make someone a terrorist. Democracies allow citizens to debate border controls, asylum procedures and government decisions. The security concern arises when individuals embrace extremist ideologies, identify targets and begin considering or preparing acts of violence.
This distinction is essential to understanding the warning.
The authorities must identify genuine threats without treating entire political movements, religious communities or groups of migrants as collectively responsible for the actions of individuals.
For MI5, the central task is to detect the point at which radicalisation becomes a credible threat to public safety.
Britain’s Terror Threat Level Returns to Severe
Another important development highlighted by McCallum was the return of the UK’s national terrorism threat level to SEVERE.
This classification means that an attack is considered highly likely. The assessment applies to the overall terrorist threat facing Britain rather than identifying one particular group as responsible for every potential danger. <Cite refs={[“turn104556search4″,”turn104556search2”]}/>
The change reflects a broad assessment of multiple risks, including extreme right-wing terrorism and Islamist extremist activity.
For the public, the announcement is a reminder that the threat environment remains serious. However, a severe threat level does not mean that an attack is inevitable or that authorities have identified an imminent attack at every location.
Threat assessments are designed to help security agencies, police forces and other organisations determine appropriate protective measures.
MI5 and its partners investigate suspected terrorist networks, gather intelligence and attempt to disrupt plots before they can be carried out. These operations often depend on cooperation between intelligence services, police forces and international partners.
The challenge is that potential attackers may operate independently or become radicalised over relatively short periods. Some may have limited contact with established extremist organisations, making their intentions more difficult to identify.
This is one reason why the security services continue to emphasise the importance of intelligence sharing and monitoring credible indications of violent activity.
The Connection Between Immigration Tensions and Extremism
The relationship between immigration and terrorism is politically sensitive because the same issue can be interpreted in very different ways.
For some members of the public, concerns about migration centre on border management, housing availability, pressure on local services and the government’s ability to enforce its own rules.
For others, the main concern is the risk that political rhetoric portraying migrants or religious minorities as collective threats could encourage hostility and create opportunities for extremist groups to recruit supporters.
McCallum’s warning focused on the second danger: the movement from extreme anti-immigration and anti-Muslim grievances towards terrorist intentions.
This does not mean that every person who supports stricter immigration controls is a security risk. Nor does it mean that immigration itself is the sole cause of terrorism.
Instead, the warning highlights the danger of individuals transforming political grievances into a justification for violence against civilians or communities.
The distinction matters because effective public policy must address both security and social cohesion.
Governments can debate how to control borders, improve asylum processing and remove people who have no legal right to remain. At the same time, they must ensure that these debates do not become a pretext for attacks on migrants, Muslims or other communities.
A democratic society can maintain firm immigration rules while protecting people from terrorism, intimidation and collective blame.
Attacks on Mosques and Asylum Accommodation Raise Concern
One of the most troubling aspects of the MI5 warning concerned individuals who had considered attacks against mosques and venues associated with immigration and asylum.
Such targets are significant because they may be selected to create fear among particular communities and to provoke wider social conflict.
An attack on an asylum accommodation site, for example, could endanger residents, staff and members of the surrounding community. An attack on a mosque could threaten worshippers and create fear far beyond the immediate location.
The consequences would extend beyond physical injuries and property damage. Such violence could deepen mistrust between communities and encourage further retaliation or intimidation.
Security agencies therefore have to assess not only whether an individual expresses extremist views but also whether there are credible signs of preparation for violence.
The challenge is particularly complicated when online propaganda encourages individuals to act independently. People may consume extremist content, become increasingly isolated and eventually develop plans without belonging to a formal terrorist organisation.
This makes early identification important.
Police and intelligence agencies must work with communities, local authorities and other institutions to recognise credible warning signs while respecting individual rights and lawful political expression.
The objective is not to suppress peaceful disagreement. It is to prevent people from turning ideological hostility into violence.
Young People Are Increasingly Vulnerable to Radicalisation
McCallum also highlighted the danger of young people becoming involved in extreme right-wing terrorism.
He revealed that MI5 had investigated a radicalised 13-year-old in the United Kingdom. He also referred to the case of a 16-year-old from Inverclyde who received a ten-year prison sentence after admitting a plan to carry out mass murder by firebombing a Muslim centre in Greenock. <Cite refs={[“turn758206view1″,”turn104556search2”]}/>
These cases underline the seriousness of online radicalisation among teenagers.
Young people can encounter extremist propaganda through social media, private messaging channels, online gaming communities and websites that promote violent ideologies.
In some cases, repeated exposure to such material can normalise dehumanising language and make violence appear justified. Individuals may also be drawn into online communities that reward increasingly extreme statements or encourage members to prove their commitment through real-world actions.
However, radicalisation does not follow a single pattern. Family circumstances, social isolation, personal grievances and exposure to particular online environments can all influence an individual’s development.
Effective prevention therefore requires more than enforcement alone.
Parents, teachers, youth workers and community organisations can play a role in identifying worrying changes in behaviour and directing young people towards appropriate support. Where there is evidence of an immediate danger, the authorities must be able to intervene.
The objective should be to prevent violence before it occurs while ensuring that young people who can be diverted away from extremism have access to meaningful alternatives.
Islamist Terrorism Remains a Serious Threat
Although the rise in extreme right-wing terrorist intentions was a major focus of McCallum’s warning, he also stressed that Islamist terrorism continues to pose a serious threat to Britain.
MI5 continues to investigate attempts inspired or directed by extremist organisations, including al-Qaeda and Islamic State.
McCallum referred to the conviction of three Islamist extremists in February for planning to use automatic weapons against the Jewish community in Manchester. The case illustrates the continuing danger of ideologically motivated violence and the potential for attacks against religious communities. <Cite refs={[“turn104556search2″,”turn758206view1”]}/>
Jewish communities have also faced threats connected to hostile activities attributed to Iran. McCallum reported more than 50 arrests in the previous year linked to Iranian-related investigations, including cases involving suspected plots and attacks against Jewish targets.
These developments illustrate the breadth of the threat confronting British security agencies.
Terrorism is not confined to a single ideology, religion or political movement. Different extremist groups may pursue different objectives, but they can share a willingness to use violence against civilians to advance those objectives.
A comprehensive counterterrorism strategy must therefore respond to evidence rather than political assumptions about which communities are inherently dangerous.
The intelligence services must identify the individuals and networks responsible for genuine threats, investigate their activities and prevent attacks wherever possible.
The Role of Online Propaganda and Artificial Intelligence
Another major concern raised by the MI5 chief was the potential misuse of artificial intelligence and digital technology.
McCallum warned that hostile states and terrorist actors could exploit AI to improve cyberattacks, refine reconnaissance and develop more sophisticated methods of planning violence. He also raised concerns about the possible misuse of technology in biological weapons development. <Cite refs={[“turn104556search5″,”turn758206view1”]}/>
Online platforms can also allow extremist propaganda to reach individuals with particular interests, grievances or vulnerabilities.
Content can be tailored to attract attention, reinforce existing prejudices and encourage increasingly extreme beliefs. Digital tools can make it easier for hostile actors to distribute propaganda rapidly and across national borders.
At the same time, it is important to distinguish between demonstrated risks and hypothetical possibilities. Not every alarming technological scenario is equally likely, and security agencies must carefully assess the evidence before deciding how to respond.
MI5 announced plans for a new AI Threat Assessment Centre to help assess these emerging risks and bring together relevant expertise.
The initiative reflects a wider recognition that national security increasingly involves both traditional intelligence work and the challenges created by rapidly changing technology.
Political Pressure on the Government
The MI5 warning is likely to intensify political debate about the government’s handling of immigration, border security and counterterrorism.
Opposition parties may argue that the authorities need stronger border controls, faster asylum decisions and more effective enforcement of immigration law.
Other voices will emphasise that counterterrorism measures must be carefully targeted and that hostility towards migrants or religious minorities can itself become a source of serious security risks.
Both border management and the prevention of extremist violence require practical solutions.
A well-functioning immigration system should process claims efficiently, enforce legal decisions and provide clarity about who has the right to remain in the country. Counterterrorism agencies, meanwhile, need sufficient resources, effective intelligence-sharing arrangements and the legal powers necessary to investigate credible threats.
However, these are related but distinct policy areas. A rise in terrorist threats cannot automatically be attributed to immigration levels, and the intelligence chief’s warning should not be interpreted as establishing such a causal relationship.
The most useful political debate would examine which measures are supported by evidence, how they could be implemented and what safeguards would be needed to protect individual rights.
Public safety is a legitimate priority, but policy decisions should be based on reliable information rather than assumptions about entire populations.
What the Warning Means for Ordinary Britons
For ordinary people, the return to a severe terrorism threat level is understandably concerning. Nevertheless, the warning should not lead to the assumption that every public place is immediately unsafe.
The authorities use threat assessments to guide security preparations and allocate resources. Members of the public can contribute by remaining aware of their surroundings and reporting credible concerns.
MI5 advises that immediate threats should be reported to emergency services on 999. Suspicious activity that may relate to terrorism can also be reported through the UK’s Anti-Terrorist Hotline on 0800 789 321. <Cite refs={[“turn104556search4″,”turn758206view0”]}/>
Equally important is the need to avoid spreading unverified allegations online. Rumours about migrants, religious communities or supposed terrorist plots can generate fear without helping the authorities identify genuine threats.
Responsible reporting and informed public discussion are essential when national security becomes a major political issue.
Communities should be able to discuss immigration policy openly while rejecting violence and intimidation. People should also be able to practise their religion, seek asylum or participate in peaceful political debate without being treated as suspects simply because of their identity or beliefs.
Conclusion: Britain Faces a Complex National Security Challenge
Sir Ken McCallum’s warning highlights the seriousness and complexity of the terrorist threat confronting the United Kingdom.
The increase in cases involving extreme anti-immigration and anti-Muslim grievances developing into terrorist intentions is a significant concern. At the same time, Islamist extremism, hostile state activity and the potential misuse of emerging technologies remain important elements of the wider security picture.
The challenge for Britain is to respond effectively without allowing fear to undermine the principles that security measures are intended to protect.
The government must ensure that immigration rules are enforced fairly, that credible terrorist threats are investigated and that public institutions have the resources needed to safeguard communities.
Political leaders also have a responsibility to distinguish between legitimate debate over immigration policy and the encouragement of hostility or violence against particular groups.
Ultimately, national security cannot be reduced to a single issue. It depends on intelligence, effective law enforcement, international cooperation, public awareness and the ability of communities to resist extremist attempts to create division.
McCallum’s warning should therefore be understood as a call for vigilance and a more comprehensive response to evolving threats, rather than as proof that migrants as a group are responsible for terrorism.
Britain’s ability to protect its citizens will depend on confronting genuine dangers with determination, evidence and careful judgement while preserving the democratic freedoms and social cohesion that remain central to the country’s security.