Security services dismissed two pieces of intelligence that could have helped them prevent the Manchester attack, a major report has found.
David Anderson QC, the former Independent Reviewer of Terrorism Legislation, said he could not prove the attack would have be been stopped but that it “might have been averted had the cards fallen differently”.
MI5 received two separate leads in the months before Salman Abedi’s bombing at Manchester Arena that were assessed as not to be linked to terrorism, when in fact they were “highly relevant” to the planned attack.
“With the benefit of hindsight, the wrong conclusions were drawn,” Mr Anderson told reporters at a briefing in London.
“Had people understood it in a different way, I think an investigation would have been opened into Salman Abedi, and who knows what it would have found.”
MI5’s internal assessment claimed that a new investigation would not have prevented the attack, but Mr Anderson said it would have “plainly been preferable” to open a new probe into Abedi.
Abedi had already been put under active investigation twice – once over his contact with another subject of interest in 2014, when he was considered a “low residual risk”, and again in October 2015 because of indirect contact with an Isis figure in Libya.
MI5 also missed the opportunity to put a notice in on Abedi that would have triggered an alert when he tried to re-enter the UK from Libya four days before the bombing, and would have allowed him to be searched and questioned at the airport.
Mr Anderson said the “hardest question to answer” was how Butt managed to launch a terror attack while under surveillance on suspicion for planning one.
Police and the Crown Prosecution Service decided not to launch a separate investigation after he was filmed praying to an Isis flag during a television documentary on a prolific group of Islamists, and believed his focus was moving away from terror attacks to travelling abroad.
An extensive intelligence operation had not flagged Butt’s accomplices Yousef Zaghba and Rachid Redouane as threats and “much remains unknown, even today, about the mindset of the three conspirators and the planning of the attack”, the report concluded.
It revealed that Zaghba was put on a Europe-wide warning list after telling officials at Bologna Airport he was travelling to Turkey to be a “terrorist”, but British authorities took no action.
Months later, Italy asked MI5 for information on Zaghba but it did not respond, possibly because the request ”arrived in the incorrect mailbox” and was not chased up.
Mr Anderson said the terror threat facing the UK “is not diminishing”, with rising numbers of suspects and shifting methods putting ever greater strain on security services.
He warned of the risk presented by 20,000 former “subjects of interest” whose investigations have been closed – the group Abedi and Westminster attacker Khalid Masood fell into.
“Their dangers are exacerbated by the fact they are not under active investigation,” Mr Anderson said in his report.
MI5 has brought in measures like reviews and data analysis to mitigate the risk but it does not always work. A meeting to reassess Abedi was scheduled to take place nine days after he committed his attack.
Meanwhile, Masood had resumed contact with the extremists linked to Anjem Choudary’s banned al-Muhajiroun group but the activity “was not picked up in any way” – despite it being the original cause of MI5’s attention.
Neither Redouane or Zaghba were known to the agency, nor was the suspected Finsbury Park attacker Darren Osborne.
Mr Anderson’s findings on that atrocity could not be published because of ongoing court proceedings, nor could those on the alleged involvement of Abedi’s younger brother in the Manchester bombing.
In a series of internal reviews, MI5 concluded its actions in all cases were “sound on the basis of information available at the time”.
But Mr Anderson made a series of 126 recommendations, including calling on MI5 to improve intelligence sharing with police and other agencies, while standardising triage assessments across the country and both Islamist and far-right terrorism.
He said neighbourhood policing was particularly crucial to counter-terror work, as forces call for more funding to mitigate real-term budget cuts in the area.
Mr Anderson also recommended increased cooperation with the private sector, such as Amazon and other online retailers, to improve the detection of potential terrorists attempting to buy explosive components and weapons.
He called for a joint “lone actor strategy” to be drawn up between MI5 and police, and to increase efforts to receive and process referrals to Prevent.
Responding to the report, Amber Rudd praised security services for their work to prevent nine terror plots thwarted so far this year, while investigating 3,000 current subjects of interest.
“We should be united in our clarity that it lies squarely with those whose cowardly acts killed 36 innocent people this year, and those who encouraged them,” the Home Secretary told the House of Commons.
“At the same time, we must learn all that we can from these attacks, and make sure our overall counter-terrorism response is equal to the shift we have seen in the threat.”
She has commissioned Mr Anderson to review the progress into his recommendations over the coming year and hinted at an increase in police funding to counter terrorism, which will be announced in the coming weeks.
Diane Abbott, the Shadow Home Secretary, said it was“worrying” that several terrorists were known to security services and called for budget increases for neighbourhood policing.
MI5 and the police said they were committed to learning and improving to meet the growing terror threat, after their internal operational improvement reviews were assured by Mr Anderson.
“Intelligence is always imperfect and counter-terrorism work requires tough professional judgements,” a spokesperson for the Metropolitan Police said. “Although we work tirelessly to keep the country safe, the reality of the terrorist threat means that we will not stop every attack.”
Cressida Dick, commissioner of the Metropolitan Police Service, said many of the reforms require new technology, and better infrastructure and resources, adding: “The growth in the number of dangerous individuals who have been radicalised is a major issue for us.
“We will be redoubling our efforts in enforcement activity both to disrupt and confront the threat and to safeguard the vulnerable from radicalisation.”
Andrew Parker, the director general of MI5, said the agency would continue to adapt to “stay ahead of the country’s adversaries” and take on Mr Anderson’s recommendations.
He added: “We and our partner agencies used the harsh light of hindsight under independent challenge to ensure we squeezed every drop of learning out of these dreadful events.
“MI5 and our partners continue to bring the full weight of our growing capabilities to counter this new intensity of threat. Our unrelenting focus remains on doing everything in our power every day to keep the country safe.”
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