Around 1,400 children were sexually exploited in one UK town over a 16-year period, according to a report.
The report on events in Rotherham, South Yorkshire, between 1997 and 2013, found that in more than a third of these cases the children were already known to agencies.
It said there had been "blatant" collective failures by the council's leadership.
Professor Alexis Jay, who wrote the report, said she found examples of "children who had been doused in petrol and threatened with being set alight, threatened with guns, made to witness brutally-violent rapes and threatened they would be next if they told anyone".
Prof Jay said: "They were raped by multiple perpetrators, trafficked to other towns and cities in the north of England, abducted, beaten and intimidated."
She said she found that girls as young as 11 had been raped by large numbers of men.
The report said failures of the political and officer leadership of Rotherham Council over the first 12 years she looked at were "blatant" as the seriousness of the problem was underplayed by senior managers and was not seen as a priority by South Yorkshire Police.
Prof Jay said police "regarded many child victims with contempt".
These failures happened despite three reports between 2002 and 2006 "which could not have been clearer in the description of the situation in Rotherham".
She said the first of these reports was "effectively suppressed" because senior officers did not believe the data.
The other two were ignored, the professor said.
The report said: "By far the majority of perpetrators were described as 'Asian' by victims."
But, she said, councillors seemed to think it was a one-off problem which they hoped would go away and "several staff described their nervousness about identifying the ethnic origins of perpetrators for fear of being thought racist".
She said: "Others remembered clear direction from their managers not to do so."
The spotlight first fell on Rotherham in 2010 when five men, described by a judge as "sexual predators", were given lengthy jail terms after they were found guilty of grooming teenage girls for sex.
The prosecution was the first of a series of high-profile cases in the last four years that have revealed the exploitation of young girls in towns and cities including Rochdale, Derby and Oxford.
Following the 2010 case, The Times newspaper claimed that details from 200 restricted-access documents showed how police and child protection agencies in the South Yorkshire town had extensive knowledge of these activities for a decade, yet a string of offences went unprosecuted.
The allegations led to a range of official investigations, including one by the Home Affairs Select Committee.
The report concluded: "No one knows the true scale of the child sexual exploitation (CSE) in Rotherham over the years.
"Our conservative estimate is that approximately 1,400 children were sexually exploited over the full inquiry period, from 1997 to 2013."
In response, Rotherham Council, which commissioned the report, said it accepted its findings, including the statement that failures "almost without exception" were attributed to senior managers in child protection services, elected councillors and senior police officers.
It accepted that failures were not down to "frontline social or youth workers who are acknowledged in the report as repeatedly raising serious concerns about the nature and extent of this kind of child abuse".