Islamist terrorism in the UK: attacks, MI5 figures and Prevent

The short answer. Islamist terrorism in the UK is still the largest part of the counter-terrorism caseload, but it is a falling share of it. MI5 said in October 2024 that roughly three-quarters of its terrorism work was Islamist, and 157 of the 275 people in custody for terrorism in Great Britain on 30 June 2026 (57%) held Islamist views.¹⁴ Most plots are stopped, but the last fatal attack, at a Manchester synagogue in October 2025, killed two worshippers, and the threat level rose to "severe" in April 2026.¹⁷⁶

Key facts #

• On 30 June 2026, 275 people were in custody in Great Britain for terrorism, the highest figure on record. Of them 157 (57%) were Islamist, 80 (29%) extreme right-wing and 38 (14%) other.¹
• MI5 and the police disrupted 43 late-stage attack plots between 2017 and October 2024. In October 2025 MI5 said 19 had been disrupted since the start of 2020.⁴⁵
• On 30 April 2026, the day after a stabbing in Golders Green, the threat level rose from "substantial" to "severe", meaning an attack is highly likely. The government said the rise was not solely due to that attack: the threat had been rising for some time, driven by a broader Islamist and extreme right-wing threat from people in the UK, against a backdrop of increased state-linked threats.⁶
• The nine fatal Islamist attacks in the UK since 2005 killed 96 people, 52 of them on 7 July 2005 (my count, from the table below).⁹
• Prevent received 8,778 referrals in 2024/25. Ten per cent concerned Islamism, 21% the extreme right and 56% no identified ideology.²⁴
• Of 3,867 terrorism arrests in the year to June 2026, 3,630 were for supporting Palestine Action, not for Islamist terrorism.¹
• On 2 October 2026 two Iranian men were charged over an alleged chlorine bomb plot against Manchester's Jewish community, said to be directed from Iran. At the Old Bailey on 23 October their trial was set for 15 June 2027 at Manchester Crown Court.³²³³

How big is the Islamist terrorism threat in the UK? #

About three-quarters of MI5's counter-terrorism work is Islamist, and about a quarter is extreme right-wing. MI5's Director General, Ken McCallum, gave that split in October 2024 and warned that the labels hide a wide range of beliefs. He added that 13% of those MI5 investigates for UK terrorism are under 18, a threefold rise in three years.⁴

The Home Office counts prisoners rather than investigations. Its figures show the Islamist share falling:

The number of Islamist prisoners has hardly moved, at 153 in 2021 and 157 in both 2025 and 2026. The share fell because the other groups grew (my arithmetic from the table).

The government says the threat level rose on 30 April 2026 after the Golders Green stabbing, but "not solely" because of it. A Security Minister's statement of 14 May said the rise was driven mainly by the Islamist and extreme right-wing threat from individuals and small groups in the UK, against a backdrop of state-linked threats including from Iran. The UK was last at "severe" from November 2021 to February 2022.⁶⁷

Headline arrest figures need care. The Home Office recorded 3,867 terrorism-related arrests in the year to June 2026, but 3,630 were for supporting Palestine Action, a proscribed group. That leaves 237 other arrests. In the same year 69 people were tried and 61 convicted, and 46 people aged 17 or under were arrested, the second-highest total since 2001.¹

What Islamist attacks have happened in the UK since 7/7? #

Nine Islamist attacks since 2005 have each killed at least one person, 96 in total, and the worst were the 7/7 bombings and the Manchester Arena. Five were in London. The table excludes the attackers from the death counts.

Other attempts did not kill. A bomb part-exploded on a Tube train at Parsons Green in September 2017, and its maker was jailed for life with a minimum of 34 years.¹¹¹⁸ Sudesh Amman stabbed two people in Streatham in February 2020, ten days after automatic release from a terrorism sentence; an inquest jury said probation had missed a chance to recall him and the attack could have been prevented.¹⁹ A bomber died in a taxi outside Liverpool Women's Hospital in November 2021.⁸

Two patterns stand out. First, known and released offenders: Khan and Amman were convicted terrorists, Butt was under investigation and Abedi was known to MI5. Parliament restricted early release for terrorists in February 2020.²⁰ Second, the shift from directed plots to lone men with simple weapons, which matches the European record of Islamic State and al-Qaeda inspiration.

Was Southport an Islamist attack? #

No. The July 2024 murder of three girls at Southport was not treated as terrorism, and the prosecutor said Axel Rudakubana had no political or religious cause, only "a longstanding obsession with violence". He pleaded guilty to possessing an al-Qaeda training manual and to producing ricin, and was told he must serve at least 52 years.²¹ False online claims that the attacker was an asylum seeker helped spark riots that summer.²¹ He had been referred to Prevent three times and each referral was closed; a 2025 review said too much weight was put on the lack of a distinct ideology.²² The Southport Inquiry's first report, in April 2026, found that no agency took ownership of the risk he posed.²³

What do Prevent referral figures show? #

Prevent is the part of the CONTEST strategy that tries to stop people becoming terrorists, and Islamism is a shrinking share of its referrals, falling from 65% in 2015/16 to 8% in the year to September 2025. Schools, health bodies, councils and prisons must have "due regard" to preventing people being drawn into terrorism.²⁶

In 2024/25, 21% of referrals (1,798) concerned the extreme right and 56% (4,917) no identified ideology.²⁴ The Home Office redesigned its categories that year and warns against comparing trends by type of concern, so treat the long fall as a guide only.²⁴

William Shawcross reviewed Prevent for the government in 2023. He wrote that 80% of counter-terrorism police live investigations were Islamist, yet only 22% of Prevent referrals in 2020/21, which he said "suggests a loss of focus".²⁶²⁷ The government accepted his 34 recommendations, and the Home Office said Islamist terrorism "remains the primary terrorist threat to the UK".²⁸ Referrals measure what teachers and doctors notice, not the danger of each case, so the falling share does not prove a falling threat.

What happened in 2026, including the Manchester plot? #

The year has brought an arson wave against Jewish sites, a stabbing in Golders Green, a higher threat level and a charged bomb plot. Labels differ between cases:

• London arson wave, from March. Mostly arson attacks hit Jewish sites. On 13 July the UK sanctioned the group that claimed them, citing hostile activity by Iran's government.³⁰
• Golders Green, 29 April. Two Jewish men were stabbed. The Metropolitan Police declared a terrorist incident, but the Crown Prosecution Service later told the court it would not pursue a terrorist connection.³¹
• Manchester, charged 2 October. Rahman Salehi, 34, and Salam Ahmadyan, 36, were arrested on 20 September. Prosecutors allege they researched a chlorine bomb and scouted the Heaton Park synagogue and the Jewish Museum. They say a third party believed to be in Iran directed them. They appeared at the Old Bailey on 23 October by video link, when a trial date of 15 June 2027 at Manchester Crown Court was set, with a preparatory hearing on 16 April 2027. Both are presumed innocent.³²³³

The Manchester case is state-directed, not the Sunni jihadism of Islamic State. I call it Iran-linked; the weekly briefing of 5 October counts it among that week's Islamist plots, and the guide to Iran's network explains the difference.

Which Islamist groups are banned in the UK? #

Britain bans groups under the Terrorism Act 2000, and since 19 January 2024 that list has included Hizb ut-Tahrir. The Home Office called it "an antisemitic organisation that actively promotes and encourages terrorism" after it praised the 7 October 2023 attacks. The Home Office did not say the group had claimed any attack.³⁴ The full list is kept on GOV.UK.³⁵

Anjem Choudary, who led Al-Muhajiroun, was jailed for life with a minimum of 28 years on 30 July 2024 for directing that banned group. He had earlier served half of a five-and-a-half-year sentence for inviting support for Islamic State.³⁶ Australia chose a lower threshold for the same group, a "prohibited hate group" listing (see Islamism in Australia). For the ideas behind such networks, see Islamist ideologues and what Islamism is.

Is the Muslim Brotherhood banned in the UK? #

No. Britain has not banned the Muslim Brotherhood. A 2015 government review found it prefers "non violent incremental change" but was "prepared to countenance violence" where gradualism fails, and that its influence in Britain was "disproportionate to their size". For balance, the review found no sign that it openly promoted an Islamic state in Britain.³⁷ In late 2025 Keir Starmer said a ban was "under very close review".³⁸ In January 2026 a Home Office minister told the Lords the government keeps proscription under review but would not comment on it.³⁹ The weekly briefing of 12 October records no later UK action. Wider Islamist aims in British law, such as Sharia councils, are in the Sharia guide.

What cuts the other way? #

• The Islamist share is falling. It was 70% of terrorist prisoners in 2021 and 57% in 2026.³¹
• Plots are mostly caught. The 43 late-stage disruptions are attacks that never happened.⁴
• Southport was not Islamist. Misattribution fed riots.²¹
• The extreme right is growing. It makes up 29% of prisoners and 21% of Prevent referrals.¹²⁴
• Prevent is contested. Prevent Watch, a campaign group, argues that the official review of the Southport case is misleading.²⁹
• Most Muslims are uninvolved. About 3.9 million people in England and Wales (6.5%) said they were Muslim in the 2021 census.⁴⁰
• Islamism is not Islam. This guide criticises a political ideology and violent networks, not Muslims as a group.

Questions people ask #

How many Islamist terror attacks has the UK had since 7/7? #

Nine Islamist attacks since the London bombings of 7 July 2005 have each killed at least one person, 96 in total. The deadliest were 7/7 (52 dead) and the Manchester Arena in 2017 (22). The most recent fatal attack was at the Heaton Park synagogue in Manchester on 2 October 2025, which killed two worshippers.

What percentage of UK terrorism is Islamist? #

It depends on the measure. MI5 says about 75% of its counter-terrorism work is Islamist. The Home Office says 57% of terrorist prisoners were Islamist on 30 June 2026. Prevent referrals are only 8% to 10% Islamist, because they include many young people with mixed or no ideology.

What is the Prevent strategy? #

Prevent is the part of the UK's CONTEST counter-terrorism strategy that tries to stop people being drawn into terrorism. Since 2015 schools, health bodies, councils and prisons have a legal duty to have due regard to it. In 2024/25 it received 8,778 referrals, and most had no identified ideology.

Is the Muslim Brotherhood banned in the UK? #

No. The group is not proscribed. A 2015 government review criticised its ideology but led to no ban. In late 2025 the Prime Minister said a ban was under very close review. In January 2026 ministers told the Lords they keep proscription under review and would not comment. No decision had been announced by October 2026.

Was the Southport attack Islamist terrorism? #

No. Prosecutors found no political or religious cause, and the attack was not treated as terrorism. Axel Rudakubana had an obsession with violence, and he possessed an al-Qaeda manual, but no ideology was established. He was sentenced to at least 52 years. Misleading online claims about him helped cause riots in August 2024.

When is the trial over the Manchester chlorine bomb plot? #

Rahman Salehi and Salam Ahmadyan, both Iranian nationals, are charged with preparing acts of terrorism. At the Old Bailey on 23 October 2026 a trial date of 15 June 2027 at Manchester Crown Court was set, with a preparatory hearing on 16 April 2027. Prosecutors allege a third person in Iran directed them. Both men are presumed innocent.

Does this mean British Muslims are a threat? #

No. Terrorists are a tiny number of men, and Islamism is a political ideology that most Muslims do not share. About 3.9 million people in England and Wales are Muslim. The right response is to target violent networks and ideas, support Muslims who oppose them, and judge each person by their actions.

Related guides #

• Terrorism hub: every guide on Islamist terrorism, groups and counter-terrorism.
• Islamist terrorist attacks in Europe: the list, Europol's counts and 2026 events.
• The Muslim Brotherhood: history, branches and the 2015 British review.
• Radicalisation: how people are drawn into extremism and what the evidence says.
• Countering Islamist extremism: what works, from Prevent to proscription.
• Islamism in Australia: Bondi, ASIO and a different legal model.

Cite as: The Analyst, "Islamist terrorism UK: attacks, MI5 and Prevent data", Fighting Islamists, updated 28 October 2026. https://fightingislamists.com/islamist-terrorism-uk.html

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