LONDON: Britain’s highest-ranking counterterrorism police officer has warned that despite improvements in the ways agencies collaborate to prevent terror attacks, they cannot stop them all and it is inevitable that there will be more.

The comment by Assistant Commissioner Neil Basu of the Metropolitan Police Service came on Monday when he appeared at the inquiry into the 2017 Manchester Arena bombing. Twenty-two people were killed, including a number of children, when 22-year-old suicide bomber Salman Abedi detonated an explosive device at an Ariana Grande concert.

Basu, who serves as the National Police Chiefs Council lead for Counter Terrorism Policing, told the inquiry: “The horror of this makes you look very hard at, hopefully, preventing it ever happening again.”

But he added: “I’m going to be very blunt about this: We won’t stop them happening again, they will happen again. We have to try and minimize or reduce the risk and that means constantly trying to have a system that looks at improvement, no matter how busy we are.”

The inquiry into the attack in May 2017 is examining the activities of emergency services, including the police and intelligence agencies, in the lead-up to the attack.

Basu said the results of a joint police and MI5 review of a number of attacks that took place in 2017, including the arena bombing, were “humbling.” That review made 104 recommendations for improvements, four of which remain outstanding.

He added that cross-agency collaboration has improved since 2017 but that more work can yet be done to better align the work of agencies.

“We’re very close but we need to be closer still,” Basu said.

The inquiry also heard from Ian Fenn, the former headteacher of a Manchester school Abedi attended between 2009 and 2011. He said Abedi was not a good student and was, at times, “aggressive and rude” to teachers, and had been suspended for theft and for setting off fireworks.

However, there was “no indication,” Fenn added, that Abedi held extremist views at that time.

“He never came across as somebody who was opinionated, who was driven, that had an agenda,” he told the inquiry. “He was a typically lackluster child who drifted around.”