Police calls from inside the foyer of the Manchester Arena where the bomb went off have been played to the inquiry as officers identified the suicide bomber and requested as many ambulances as possible.
Inspector Michael Smith from Greater Manchester Police was seen on a bomb-damaged CCTV camera as he arrived in the City Room foyer with colleagues, 18 minutes after the explosion.
A minute later, at 10.50pm on 22 May 2017, he radioed in to his control room and told them he needed Victoria Station, underneath the arena, clearing and staff from the North West Ambulance Service (NWAS).
“Looks like what I said before is right, the booking hall is the seat of the explosion, not the arena itself,” he said.
“There’s some walking wounded, we have a lot of casualties in here…I need every NWAS facility that we’ve got in here please, directly in here.”
Three minutes later, at 10.53pm, PC Richardson, the operational firearms commander, gave an update to Insp Dale Sexton, the force duty officer, from inside the arena.
He told him: “Any medical assistance you can give, we have max casualties. Does look like a nail bomb, loads of shrapnel inside.
“We do believe the male responsible is in the middle of the arena and a mess. Have you got any movement on an explosive dog? I appreciate also we just need more ambo staff, anyone we can get hold of please.”
Insp Sexton told him: “I’m trying to get as many NWAS down there as possible. We’ll try and get the explosives dog.”
At 10.54pm, a minute after he had entered the City Room, advanced paramedic Patrick Ennis updated: “This is to confirm a major incident. We’ve got at least 40 casualties. Approximately 10 appear to be deceased on scene, at least a dozen priority one.”
Firearms officers could be seen running towards the scene of the attack and then returning to fetch medical bags.
The officers were pointed the way by British Transport Police PC Carl Roach.
The inquiry was also played the moment a senior officer wrongly declared the attack a marauding firearms incident, apparently thinking he had declared it a terrorist attack.
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A recording was played to the inquiry in which Insp Sexton spoke to GMP Night Silver Commander Superintendent Arif Nawaz and declared “Operation Plato”.
The effect of the decision would have been to exclude emergency service workers from going into the so-called “hot zone” in case they got shot, but the declaration was never passed on.
At 10.50pm, Insp Sexton told Supt Nawaz: “We have confirmed ten dead with multiple injuries to other people, significant numbers. Still trying to make sure there’s no further devices inside.
“Obviously with that in mind we will try to clear the members from outside so we have a sterile area need some more resources to deal with that from other divisions.
“Looks like a male had the device strapped to him and exploded it, ball bearings inside. I have declared Operation Plato which is a terrorist attack.
“On the face of it, at the moment we’ve only got one individual, a lone terrorist but have to bear in mind it might escalate further.
“We’ve got the authority to do an emergency search of the premises, obviously bearing in mind we have a load of casualties there as well.”
Salman Abedi killed 22 men, women and children when he blew himself up in a suicide bomb attack at the end of an Ariana Grande concert in May 2017.
The inquiry continues.