It follows after the head of the security service admitted last year that there was only a “slim” chance to stop the attack in May 2017, which left 22 people dead and hundreds injured.
Since then, three law firms on behalf of over 250 individuals have acknowledged that a case has been brought before the Investigatory Powers Tribunal (IPT). They have not, however, disclosed any additional information, citing the case as a “ongoing legal matter”.
According to a March 2013 investigation, the bombing might have been avoided if MI5 had taken action on information gathered in the months prior to the assault.
The security service had determined at the time that two pieces of information regarding bomber Salman Abedi had nothing to do with terrorism, according to findings.
