London, Mar 3 (IANS): A "significant" opportunity to prevent the 2017 Manchester Arena attack that killed 22 people was missed by the UK security services, a public inquiry has revealed.

"The reasons for this significant missed opportunity included a failure by a Security Service officer to act swiftly enough," said inquiry chairman John Saunders.

Although it is impossible to definitively prove that the attack could have been stopped, "there was a realistic possibility that actionable intelligence could have been obtained which might have led to actions preventing the attack", Xinhua news agency quoted the report as saying.

Former reports by Saunders have found "serious shortcomings" and missed opportunities by security services to prevent the "devastating impact" of the bombing.

The first of three reports published by the public inquiry, which began in September 2020, has levelled criticism at British Transport Police, the arena operators, and their contracted security providers.

An Islamist extremist suicide bomber detonated a homemade bomb as people were leaving the Manchester Arena after a concert by the singer Ariane Grande on May 22, 2017.

It was the worst terror attack in Britain since the London bombings in 2005, in which 52 people died.