Video report by Amy Welch
The Manchester Arena Inquiry has been hearing from senior officers with British Transport Police who have admitted failings in co-ordinating the emergency response after the bomb went off.
The inquiry's heard details about communications on the night of the attack, including evidence that staff in the BTP control room who had to dial 999 to talk to Greater Manchester Police officers.
Within minutes of the suicide bomb attack at the Manchester Arena, British Transport Police officers were seen running to Arena to help. Their bravery has already been praised.
But it's the failures of the forces most senior officers which is now the focus of this part of the inquiry.
Robin Smith, gold commander for the incident, admitted he had "no clear sense" of the whereabouts of his bronze commander Superintendent Kyle Gordon, tasked with co-ordinating events at ground level.
The inquiry into the May 2017 terror attack has heard Supt Gordon was tasked to attend the venue at 11.12pm but did not arrive until after 1am - more than two-and-a-half hours after the suicide bomb detonated by Salman Abedi went off in the City Room foyer.
Chief Superintendent Allan Gregory, silver commander following the attack, previously told the hearing it was a "source of regret" he gave Supt Gordon the role, with "better choices" in hindsight.
Then-assistant chief constable Mr Smith - now Chief Officer of Jersey Police - said he knew Supt Gordon and had met him but did not know his then whereabouts in relation to Manchester Arena.
Nicholas de la Poer QC, counsel to the inquiry, asked: "Did you as gold commander have a clear sense of how long it would take for Supt Gordon to attend the scene?"
Mr Smith replied: "I did not."
He said he would have asked "are there alternatives" if he had known it would take Supt Gordon at least an hour to get to Manchester Arena - on land owned by Network Rail.
Mr Smith was instructed to travel from the South East to Manchester and arrived in time at Greater Manchester Police's (GMP) force headquarters for a strategic co-ordinating group meeting at 4.15am.
But he told the inquiry he had not received a tactical plan on the response of BTP by that stage.
He said: "I received, if you like, parts of a tactical plan but what we expect as a tactical plan, no."
Mr Smith said normally he would anticipate such a plan "probably within the first half-hour", depending on the demands of the silver commander.
The inquiry is looking at events before, during and after the explosion on the evening of May 22 which killed 22 people and injured hundreds at the end of an Ariana Grande concert.