At least 1400 children were subjected to appalling sexual exploitation in the English city of Rotherham between 1997 and 2013, a report has found.
Children as young as 11 were raped by multiple perpetrators, abducted, trafficked to other cities in England, beaten and intimidated, it said.
The report, commissioned by Rotherham Borough Council, revealed there had been three previous inquiries.
Council leader Roger Stone said he would step down with immediate effect, the BBC reported.
Mr Stone, who has been the leader since 2003, said: "I believe it is only right that as leader I take responsibility for the historic failings described so clearly."
The inquiry team noted fears among council staff of being labelled "racist" if they focused on victims' description most abusers as "Asian" men.
Professor Alexis Jay, who wrote the latest report, said there had been "blatant" collective failures by the council's leadership, senior managers had "underplayed" the scale of the problem and South Yorkshire Police had failed to prioritise the issue.
Prof Jay said: "No one knows the true scale of child sexual exploitation in Rotherham over the years. Our conservative estimate is that approximately 1400 children were sexually exploited over the full inquiry period, from 1997 to 2013."
Revealing details of the inquiry's findings, Prof Jay said: "It is hard to describe the appalling nature of the abuse that child victims suffered."
The inquiry team 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".
Five men from the town were jailed for sexual offences against girls in 2010 but the report said police "regarded many child victims with contempt".
District Commander for Rotherham Chief Superintendent Jason Harwin said: "Firstly I'd like to start by offering an unreserved apology to the victims of child sexual exploitation who did not receive the level of service they should be able to expect from their local police force.
"We fully acknowledge our previous failings."
Mr Harwin said the force had "overhauled" the way it dealt with such cases and had successfully prosecuted a number of abusers.
But he admitted: "I accept that our recent successes... will not heal the pain of those victims who have been let down."
A victim of abuse in Rotherham, who has been called "Isabel" to protect her identity, told BBC Panorama: "I was a child and they should have stepped in.
"No matter what's done now... it's not going to change that it was too late, it should have been stopped and prevented."