Ariana Grande Attack 'May Have Been Preventable'

MI5 might have been able to prevent the attack on an Ariana Grande concert in Manchester that killed 22 people in May if it had analysed intelligence differently, according to a report.

Former independent reviewer of terrorism legislation David Anderson QC found that "It is conceivable that the Manchester attack in particular might have been averted had the cards fallen differently."

Anderson's words came in a report that examined nine classified internal reviews carried out by MI5 and the police into their handling of four attacks on London and Manchester in Spring 2017.

Salman Abedi, who carried out the Manchester suicide bombing, was "not under active investigation at the time of his attack," the report said.

But, it continued, "MI5 nonetheless came by intelligence in the months before the attack which, had its true significance been properly understood, would have caused an investigation into him to be opened."

Manchester Attack Memorial
People attend a vigil for the victims of last week's attack at a pop concert at Manchester Arena, in central Manchester, Britain May 29, 2017. Andrew Yates/Reuters

The report does not divulge full details of evidence held on Abedi, but it said: "On two separate occasions in the months prior to the attack, intelligence was received by MI5 whose significance was not fully appreciated at the time.

"It was assessed at the time to relate not to terrorism but to possible non-nefarious activity or to criminality on the part of Salman Abedi.

"In retrospect, the intelligence can be seen to have been highly relevant to the planned attack."

"I offer no view on whether the re-opening of an investigation into Salman Abedi in early 2017 would, as MI5 concludes 'on the clear balance of professional opinion,' have been unlikely to result in the pre-emption of the gathering plot," Anderson said.

But, he added: "I prefer to emphasise my agreement with the other point made in this connection: that 'there is a high degree of inherent uncertainty in speculating as to what might or might not have been discovered.'"

In addition, Anderson said, an MI5 technique intended to identify former subjects of interest who might merit further attention identified Abedi as one of a "small number" of such subjects.

But a meeting at which the results of this process were to be considered was scheduled in advance of the attack for May 31, nine days after the attack took place.

The report also details how Khuram Butt, ringleader of another attack on London Bridge in June that killed eight people, was under investigation by MI5 before he carried out the atrocity.

"[Butt] was the principal subject of an MI5 investigation," Anderson wrote, "opened in mid-2015 following information suggesting that he aspired to conduct an attack in the UK.

"Coverage of various kinds was put in place over a period of almost two years.

"Though it continued to varying degrees until the day of the attack, it did not reveal the plans of Khuram Butt and his two co-conspirators," the report said.