A gang of men from Derby has been convicted of systematically grooming and sexually abusing teenage girls.
Many of the victims were given alcohol or drugs before being forced to have sex in cars, rented houses or hotels across the Midlands.
One girl described a sexual assault involving at least eight men.
The nine men were convicted during three separate trials, culminating in the convictions at Leicester Crown Court of the two ringleaders.
Reporting restrictions had been in place until the end of the third trial.
Twenty-seven girls came forward to say they had been victims, the youngest of whom was 12 and the oldest was 18. Convictions have been achieved for 15 of those.
Abid Mohammed Saddique, 27, and Mohammed Romaan Liaqat, 28 - both married with children - were said to be the leaders of the gang.
Saddique, of Northumberland Street, Normanton, Derby, was convicted of four counts of rape as well as two counts of false imprisonment, two of sexual assault, three charges of sexual activity with a child, perverting the course of justice, and aiding and abetting rape.
Liaqat, of Briar Lea Close, Sinfin, Derby, was found guilty of one count of rape, two of sexual assault, aiding and abetting rape, affray, and four counts of sexual activity with a child.
Both pleaded guilty to causing a person under the age of 18 to be involved in pornography.
They will be sentenced on 7 January.
Derbyshire Police said they believed no money changed hands between those involved, and said such instances of abuse were a growing problem in the UK.
Detectives said it had been the most horrendous case of sexual exploitation they had ever faced.
The undercover investigation by Derbyshire Police, Operation Retriever, was split into three trials which have run since February.
Speaking after the hearing, Det Insp Sean Dawson said: "These convictions have brought an end to a lengthy and complex investigation that has been brought to court thanks to the bravery of the victims in this case.
"These two men are predatory sex offenders who, with their associates, have systematically abused and raped teenage girls.
"We are shocked by the scale of abuse we have uncovered and the impact it has had on the girls who were the victims of these callous men.
"Child sex exploitation is something that parents and carers across the country should be aware of.
"Parents and carers should talk to their children, take an interest in what they are doing and warn them not to go off with strangers, no matter how tempting it might seem."
Thirteen men were charged in relation to Operation Retriever and 11 stood trial for a string of charges, not all sexual, relating to the case.
Of the original 13, a total of nine have been convicted of offences against vulnerable girls ranging from rape to false imprisonment.
Other defendants already convicted and sentenced were: Akshay Kumar, 38, he admitted one count of causing a person under the age of 18 to be involved in pornography and was jailed for two years and 10 months.
Faisal Mehmood, 24, pleaded guilty to sexual activity with a child before trial and was jailed for three years. He has now been deported to Pakistan.
Mohammed Imran Rehman, 26, was jailed for seven-and-a-half years after being found guilty of rape, while Graham Blackham, 26, was given a three-year sentence after he was convicted of two counts of breaching a sexual offences prevention order.
Liaqat's brother Naweed Liaqat, 33, and Farooq Ahmed, 28, pleaded guilty to perverting the course of justice and were both jailed for 18 months.
Ziafat Yasin, 31, was cleared of sex charges but pleaded guilty to being concerned in the supply of cocaine. He was jailed for three years.