While still a teenager, Abedi traveled from his home in Manchester to Libya, where he fought with a jihadist militia opposed to Colonel Gaddafi.
file closed
MI5 was first alerted to concerns about its radicalization potential in 2014, but at no point was Prevent, the government’s counter-extremism programme, mentioned.
In March 2014, after receiving intelligence, Abedi was declared a “subject of interest”, meaning that he was formally placed under investigation by MI5.
But just four months later, the file on him was closed after it was determined that he did not pose a significant threat.
The file was reopened in October of that same year but this time it was closed after only one day.
The Telegraph understands that Thursday’s report will be particularly critical of deficiencies in MI5’s system for monitoring subjects of interest such as Abedi, who are not under active investigation.
Sir John is believed to recommend that more work be done to monitor suspects who are low on the priority list but still pose a potential risk.
Abedi authorized to continue traveling
While Abedi’s case had been flagged for review, this had not been the case when he launched his attack.
In November 2015, Abedi flew to Germany but returned to the UK the next day, prompting MI5 to consider whether he had been trying to travel to Syria to join the Islamic State of Iraq and the Levant (ISIL).
In May 2016, he was again reported to the Security Service after police raised concerns about trips he made to Turkey and Libya.
But in both cases the suspicions were not fully investigated and Abedi was able to continue to travel freely without restrictions.
In the months leading up to the attack, MI5 received intelligence relating to Abedi on two separate occasions. But the information was dismissed at the time as “non-terrorist criminality.”
A report by parliamentarians on the Security and Intelligence Committee said that in hindsight the information could be considered “highly relevant” to the planned attack.
Abedi met with convicted terrorist
The Security Service also knew that Abedi was in regular contact with the convicted terrorist, Abdalraouf Abdallah, who was serving a prison sentence for helping people travel to Syria to join ISIL.
In early 2017, when he was building the bomb, Abedi visited him in prison and spoke to him regularly through an illegal cell phone.
Sir John is expected to be scathing about MI5’s failure to connect the dots and connect numerous small pieces of intelligence regarding Abedi.
The report will make extremely sobering reading for MI5, which has previously faced criticism for failures related to the July 7 bombings, the Westminster and London Bridge attacks and the Fishmonger Hall atrocity.
During the public inquiry, MI5 lawyers said the agency’s decisions on Abedi had to be seen in the context of an “unprecedented” scale of terror threats in 2017.
There were five successful terrorist attacks in Britain that year and numerous plots that were successfully disrupted and prevented.
Cathryn McGahey KC told the hearing that Abedi was one of 20,000 closed subjects of interest and that investigators faced difficult decisions.
“Making such decisions inevitably means running the risk of an attack being carried out by someone MI5 chooses not to investigate,” he said.
‘Significant missed opportunities’
MI5 has admitted missed opportunities but insists its decisions were reasonable based on intelligence at the time.
But a lawyer for the families of the victims told The Telegraph that police and intelligence agencies missed “significant opportunities” to apprehend Salman Abedi.
Richard Scorer, a lawyer with Slater and Gordon who represents 12 of the families of the victims, said: “It appears important opportunities to apprehend Abedi were missed.
“We and our clients expect Sir John to look at what happened, and all the various failures, as forensically and ruthlessly as he has in previous reports, and make far-reaching recommendations.
“Only by doing this can we hope to learn the lessons of the Arena bombing and ensure future attacks are prevented.”