A hearing was told that the inquiry into the 22 killings, scheduled to start on 6 April next year, could be delayed because of the failure to explain police “command and control” on the night.
The inquiry was also told that police have handed over 550 hours of audio recordings from police radios which had not been transcribed.
The inquiry has transcribed the recordings themselves, but subsequently found gaps in them.
The counsel for the inquiry acknowledged the “concern, suspicion and even distress” families have experienced after it was announced that parts of the hearings about what MI5 knew about Salman Abedi, the bomber, will take place in secret.
Responding to the criticism, Fiona Barton QC, who is representing Greater Manchester Police, turned to the families at the hearing and said: “I apologise profusely for the delay. May I reiterate GMP’s commitment to the start date.”
He criticised Chief Constable Ian Hopkins, saying: “One might have thought the chief constable would have sent down the line the clearest of instructions that the response to the Manchester bombing had to be done to the highest possible level.
“Greater Manchester Police really have to answer here as to why it has dragged its feet to the extent that counsel is saying there is potential jeopardy to the date.”
Sir John Saunders, the chairman of the inquiry, said he was “absolutely insistent” that the inquiry had to start on 6 April.
“It is simply not fair to the families to wait longer than that, or to Manchester in general. If there is a delay I have no doubt there will be extremely extensive public criticism of Manchester police.”
The inquest into the 22 deaths has been converted into a public inquiry so that parts of evidence from GMP and MI5 of “central importance” can be heard in secret.
It will be the first time that an inquiry into a terrorist attack on mainland Britain since 9/11 has taken place partly behind closed doors.
Mr Greaney acknowledged that there was “concern, suspicion and even distress” on the part of the victims’ families.
“What everyone must understand is that you have not ruled in this way to protect the police and security service from scrutiny. Nothing could be further from the truth,” he added.
Sir John told them: “All I can say is that I will hold a completely rigorous and proper inquiry. I am sorry they will not be able to hear it take place.”
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