List of terror attacks where perpetrators were known to MI5

The Fishmongers’ Hall attack was one of a number of terrorist atrocities where the perpetrator was known to the security service MI5.

Most of the incidents have been unsophisticated attacks involving knives and sometimes vehicles, which involve less planning and are harder to detect.

Despite MI5 and the police foiling 29 terror attacks since March 2017, the security service and counter-terrorism chiefs have repeatedly faced questions about how outrages have occurred when the killers were known to the authorities.

– May 2013: Murder of Lee Rigby 

Young soldier Lee Rigby was run over and stabbed by Michael Adebolajo and Michael Adebowale in south-east London. Both men had previously been investigated by MI5.

Adebolajo also claimed he had been visited at home by officers from the security service when he returned from Kenya in 2010, having been captured trying to travel to Somalia to join extremist group al-Shabab.

Khalid Masood mowed down pedestrians on Westminster Bridge, killing four and injuring dozens more, before storming through gates near the Houses of Parliament and fatally stabbing unarmed Pc Keith Palmer.

The security service’s knowledge of Masood’s contact with known terrorists over 13 years came under heavy scrutiny during the inquests into the deaths.

Senior MI5 officer Witness L said the attack could not have been prevented because Masood acted alone, there was not enough intelligence to have stopped the plot, and the decisions not to investigate him more thoroughly were sound.

He said Masood’s offensive extremist views, history of violence from 1998 to 2003 and his links with multiple terror suspects were not enough to scrutinise him more closely.

Intelligence on bomber Salman Abedi came in to MI5 for six years, and right up to the months before he blew himself up with a homemade bomb, packed with shrapnel, murdering 22 bystanders and injuring hundreds more in the foyer of Manchester Arena at the end of an Ariana Grande concert.

He was identified associating with six separate MI5 “subjects of interest”, visited a terrorist twice in jails, and regularly travelled to war-torn Libya.

On one occasion, Abedi had himself been made a “subject of interest”, but his file was closed five months later in July 2014.

A public inquiry is currently being held into the attack, including what MI5 knew about Abedi, but the security service admitted in 2018 that it had reacted too slowly in assessing the risk he posed.

Khuram Shazad Butt, 27, Rachid Redouane, 30, and Youssef Zaghba, 22, killed eight people and injured dozens more when they ploughed a van into pedestrians on London Bridge and then began stabbing people around Borough Market.

Butt had previously come to the attention of MI5 in 2014, under an alias, as part of an investigation into potential terrorist attack planning in the UK.  He was investigated for various periods over the next three years.

In early 2016 Butt appeared in a Channel 4 documentary called The Jihadis Next Door, which was watched by MI5 staff.

He had brushes with the law, including being arrested for fraud in October 2016, but there was not enough evidence to bring charges.

All three attackers attended a gym that was owned by a suspected extremist and member of banned group al-Muhajiroun, although MI5 failed to identify the site as being significant.

Zaghba nearly outed himself in March 2016, when he was stopped trying to fly from Bologna to Istanbul.

He accidentally told airport officials he was travelling “to be a terrorist”, before correcting himself to “tourist”.

Italian officials put a serious crime alert on Zaghba, and the following month contacted MI5 for more information but received no response. This was put down to an admin error.

Iraqi asylum seeker Ahmed Hassan’s homemade bomb partially exploded on a London Underground rush-hour train at Parsons Green, injuring more than 50 people. He was sentenced to life with a minimum jail term of 34 years.

Following his arrival in Britain in 2015, Hassan told Home Office officials he had been trained to kill by Islamic State.

He was referred by Barnardo’s and Surrey social services to anti-radicalisation scheme Prevent, but was never referred to MI5.

He kept his murderous plans secret from counter-terrorism and support workers, as well as his foster parents.

Usman Khan was shot by armed police on London Bridge, approximately 15 minutes after he strapped kitchen knives to his hands and fatally stabbed Cambridge University graduates Jack Merritt and Saskia Jones at nearby Fishmongers’ Hall.

He was jailed in 2012 for plotting a terror camp in his parents’ homeland of Pakistan, and was known in prison as the “main inmate” for extremist views.

Khan was so notorious, in fact, that he was classed as being among the top 0.1% of the most dangerous prisoners in England and Wales when he was released into the community as a category A, high-risk offender on Christmas Eve 2018.

MI5, which had already launched a covert investigation with West Midlands Police supported by Staffordshire Special Branch, had intelligence that Khan was planning to “return to his old ways” and aspired to carry out an attack.

Yet the information was not passed on by police to others involved in Khan’s management in the community and the “old ways” intelligence was labelled “low grade”.

An inquest jury concluded failings in Khan’s management in the community and information-sharing and guidance by agencies responsible for monitoring or investigating Khan contributed to the deaths.

Sudesh Amman, 20, was under 24-hour police surveillance when he stabbed two people while wearing a fake suicide vest on a south-London high street.

He had been released from prison on January 23, after being jailed in December 2018 for possessing and distributing terrorist documents.

At the time of his release he was viewed as an “extremely concerning individual”.

He was killed by police marksmen after launching his attack.

In the wake of the atrocity, Metropolitan Police boss Dame Cressida Dick said the surveillance was not “man-to-man marking”.

Failed Libyan asylum seeker Khairi Saadallah was briefly known to MI5 before the fatal knife attack in a Reading park in which he murdered James Furlong, 36, David Wails, 49, and Joseph Ritchie-Bennett, 39, and injured another three people.

The information given to the security service, that he planned to travel abroad possibly for terrorist purposes, did not meet the threshold for investigation.

Saadallah had fought for the extremist Ansar al-Sharia group in Libya, and once in the UK racked up a string of convictions for crimes including violence and knife possession.

In prison, he sought out radical preacher Omar Brooks, an ALM member.

He was released from HMP Bullingdon weeks before the attack, and was visited by police officers on the day before, but they left when he told them he was “all right”.