TerrorismThe Manchester bombing: unknown unknowns and “hindsight bias”

By Dan Lomas

Published 6 December 2017

The May 2017 Manchester Arena bombing could have been prevented, a report by the former Independent Reviewer of Terrorism Legislation has revealed. David Anderson QC’s report suggests there were opportunities to reopen the case, raising the possibility the attack could have been stopped. Newspaper headlines, however, are misleading, neglecting the nuance in Anderson’s report that the decision to ignore or misinterpret the intelligence on Abedi was “understandable” in the circumstances, overlooking the complex nature of counter-terror investigations. So, could the Manchester bombing really have been prevented?

The May 2017 Manchester Arena bombing could have been prevented, a report by the former Independent Reviewer of Terrorism Legislation has revealed. The 22-year-old attacker Salman Abedi, who killed 22 people and injured 512 others, had been a “subject of interest” to Britain’s Security Service (MI5) in 2014 and 2015 but was classed as a “low residual risk” to national security and his case was closed.

David Anderson QC’s report suggests there were opportunities to reopen the case, raising the possibility the attack could have been stopped. MI5 twice received intelligence reports which – had their significance been “properly understood” – would have reopened the investigation into Abedi. The intelligence was not “fully appreciated” and judged to “relate not to terrorism” but possible “nefarious activity or criminality”. Abedi was just one of a number of closed subjects of interest (SOI) whose case needed “further consideration”. A meeting to review the evidence was scheduled for 31 May 2017 – nine days after the Manchester Arena bombing.

MI5 had also missed the opportunity to place a port alert on Abedi following a visit to Libya in April 2017. Had they done so, Abedi could have been questioned and searched by counter-terror police four days before the attack. As with the Westminster Bridge attacker, 52-year-old Khalid Masood, Abedi was judged to pose little threat, yet struck with devastating results.

The findings form part of a review requested by Home Secretary Amber Rudd to provide “independent assurance” of internal reviews by the police and MI5, to assess intelligence and decisions before the attacks, and to “identify whether the processes and systems … can be improved”.

Greater Manchester Mayor Andy Burnham said Anderson’s report would be a “difficult read” for Mancunians, adding: “It is clear that things could, and perhaps should, have been done differently and that wrong judgements have been made.”

The report led to a series of headlines suggesting MI5 had been caught napping. BBC News claimed the attack “could have been stopped,” The Financial Times ran with the story that Abedi could have been “prevented”, while The Daily Mail suggested MI5 had missed a series of red lines and were “alerted months” before the Manchester Arena blast. One commentator concluded that Anderson’s conclusions are “damning for MI5.” The implication being a so-called “intelligence failure” had occurred.