Manchester Arena bomber Salman Abedi was known to security services and his attack ‘might have been averted’, an official review has confirmed.
MI5 came by unspecified intelligence about Abedi in the months before his bomb attack killed 22 adults and children outside an Ariana Grande concert, a security review by David Anderson QC revealed.
The information would have caused an investigation into him to be opened ‘had its true significance been properly understood’.
But instead, Abedi was not under active investigation when he detonated his suicide device at Manchester Arena in May.
The report says: ‘It is unknowable whether such an investigation would have allowed Abedi’s plans to be pre-empted and thwarted. MI5 assesses that it would not.’
Abedi was also identified by a separate ‘data-washing exercise’ as falling within a small number of former subjects of interest who merited further consideration.
However, a meeting scheduled to consider the results of this process had not been held at the time of the bombing, in which 22 people were killed.
An opportunity was also missed to place Abedi on ‘ports action’ after he travelled to Libya in April.
UK’s security services faced questions after dozens of victims were killed or injured in attacks at Westminster, Manchester, London Bridge, and Finsbury Park this year.
MI5 and police launched independent reviews to examine what was known about the terrorists before they struck, decisions made on intelligence and possible areas for improvement.
The review, published today, discloses that three terrorists involved in four attacks that hit Britain between March and June this year had at some point been on authorities ‘ radar.
The scale of the threat facing the UK was laid bare in today’s report.
It revealed counter-terror teams are running about 500 live investigations involving 3,000 individuals at any one time, while there is also a wider pool of 20,000 subjects previously looked at who must be kept under review.
A total of nine Islamist terrorist plots have been thwarted in the UK over the past year, the director general of MI5 has told Cabinet earlier today.
Outlining the review findings, Home Secretary Amber Rudd told the Commons: ‘Based on the MI5 and police reviews, David Anderson explains that in the case of the Westminster attack, Khalid Masood was a closed subject of interest at the time of the attack.
‘Neither MI5 nor the police had any reason to anticipate the attack.
‘Regarding the Manchester Arena attack, Salman Abedi was also a closed subject of interest at the time of the attack, and so not under active investigation.
‘In early 2017, MI5 nonetheless received intelligence on him, which was assessed as not being related to terrorism.
‘In retrospect, the intelligence can be seen to be highly relevant.
‘Had an investigation been reopened at the time, it cannot be known whether Abedi’s plans could have been stopped.
‘MI5 assess that it would have been unlikely.
‘Across the attacks, including Manchester Arena, David Anderson notes that MI5 and CT policing got a great deal right.
‘However, in relation to Manchester, he also commented that, quote, ‘it is conceivable that the attack might have been averted had the cards fallen differently’.’
Khuram Butt, who led the three-strong gang behind the London Bridge van and knife attack in June, was the principal subject of an MI5 investigation from mid-2015 until the date of the deadly assault.
The report says material relating to Butt received in the two weeks prior to the attack added little to the intelligence picture and did not identify activity that led up to the attack.
Another of the London Bridge gang, Youssef Zaghba, was placed on an EU warning list in March last year but a marker which would have automatically identified him as a national security risk was deleted by Italian authorities in January.
In June 2016, MI5 received an inquiry from Italian authorities about Zaghba but the agency has no record of responding – ‘noting by way of possible explanation that it arrived in the incorrect mailbox’.
The request was not chased up by Italian officials.
Zaghba, and the third London Bridge attacker Rachid Redouane, were never investigated by MI5.
Police and MI5 have foiled nine plots since the Westminster attack in March, in addition to the terrorist incidents that have occurred.
The full internal reviews, which are highly classified and run to more than 1,100 pages, contain 126 recommendations.
Mr Anderson said: ‘In particular, MI5 and the police have identified the need to use data more effectively, to share knowledge more widely, to improve their own collaboration and to assess and investigate terrorist threats on a uniform basis, whatever the ideology that inspires them.’
Khalid Masood, 52, killed five people and injured nearly 50 when he drove a hired 4×4 along the pavement of Westminster Bridge before stabbing a policeman outside Parliament.
Masood (right) was a low level criminal who racked up a number of convictions while growing up in Kent and Sussex.
But he changed his name from Adrian Ajao to Masood and was rarely seen by his family after a 2003 prison sentence for a violent attack.
Instead he moved into an area of Luton known for its extremism and was alleged listed as a contact for a website which slammed Christians and Jews urged ‘war’ against ‘the enemy of Allah’.
It emerged today he was known to police and MI5 for association with extremists.
But he was a closed subject of interest at the time of the atrocity in March, and intelligence officers and police had no reason to anticipate his murderous actions, according to the report