A series of "unacceptable and unjustified" security failures occurred before Manchester Arena suicide bomber Salman Abedi murdered 22 innocent people, a public inquiry has heard.
Hundreds more were injured in the blast and lawyers for those who died heaped criticism on both private firms and public bodies responsible for security at the arena, with a long list of "missed opportunities" cited.
The inquiry, before retired High Court judge Sir John Saunders, is hearing final submissions on chapter seven of the inquiry, relating to security at the venue, run by corporate giant SMG, which employed Showsec, another major company, to provide security and stewarding.
Both firms were focused on keeping costs down and had become "complacent" over security, it was claimed.
British Transport Police (BTP), who had "primacy" in policing as the venue is at Manchester Victoria railway station, and Greater Manchester Police (GMP), the local lead on counter-terrorism, also came under fire.
Duncan Atkinson QC, representing the families of seven people murdered by Abedi and his brother Hashem, suggested complacency had set in, with a "tick-box" mentality to security.
Earlier, the inquiry heard how Salman Abedi had carried out "hostile reconnaissance" in the days leading up to the attack on May 22 2017, which was not picked up.
On the day of the bombing, Abedi, dressed all in black and carrying a large rucksack, had repeatedly visited the City Room, the foyer to the arena.
In that time, security was alerted by members of the public to his "dodgy" appearance but no action was taken, one man was "fobbed off" and Abedi was never approached or the threat identified by any Showsec staff or BTP officers.
Mr Atkinson said Abedi's presence was "obviously suspicious and out of place" but the security operation at the arena was "under-resourced, mal-co-ordinated and insufficiently focused on counter-terrorism", especially a threat from a suicide bomber.
This led to a "series of missed opportunities to prevent, deter, detect and, or, mitigate the attack".
Mr Atkinson added: "In short, the evidence shows the attack to have been, at least in significant part, the result of a failure of reasonable foresight, a failure to anticipate and address a risk that should have been obvious, rather than a failure that only hindsight reveals."
He said risk assessments for terror attacks at the arena were clearly flawed despite the national threat level being severe, and both SMG and Showsec were focused not on risks to the audience but risks of the audience, and they had become complacent.
CCTV cameras were not always monitored, there were not enough staff to do so and they were not adequately trained, Mr Atkinson said.
Finally there were not enough Showsec staff, with SMG focused on reducing costs and Showsec on "remaining competitive", its casualised workforce, paid the minimum wage, often young and inadequately trained, the inquiry heard.
Peter Wetherby QC, representing seven more families, said it was "blindingly obvious" SMG, an "enormous corporate enterprise", should have employed a dedicated counter-terrorism expert to look after the arena but it did not.
He added: "SMG took the money for ensuring security and public safety in the City Room but very plainly failed to discharge those responsibilities."
The inquiry continues.