Girls as young as 11 "expect" to have to perform sex acts on rows of boys for up to two hours at a time in parts of London, a watchdog said in a warning that serious child abuse is rife right across England.
Deputy Children's Commissioner Sue Berelowitz said her in-depth study of the problem suggested there "isn't a town, village or hamlet in which children are not being sexually exploited".
And she shocked MPs with a graphic description of just some of the crimes she had encountered in her research for a major report due out in September.
Giving evidence to the Commons home affairs committee, Ms Berelowitz said the recent sex abuse case in Rochdale - which involved mostly men of Pakistani origin and white girls - was just one part of a wider picture of exploitation involving victims and abusers of all races and cultures.
"What I am uncovering is that sexual exploitation of children is happening all over the country," she told the cross-party committee.
"As one police officer who was the lead in a very big investigation in a very lovely, leafy, rural part of the country said to me: 'there isn't a town, village or hamlet in which children are not being sexually exploited.
"The evidence that has come to the fore during the course of my inquiry is that that, unfortunately, appears to be the case.
"We should start from the assumption that children are being sexually exploited right the way across the country.
"In urban, rural and metropolitan areas, I have hard evidence of children being sexually exploited. That is part of what is going on in some parts of our country. It is very sadistic, it is very violent it is very ugly."
Giving examples from the capital, she said: "There are parts of London where certainly children expect to have to perform oral sex on line-ups of boys, up to two hours at a time from the age of 11."