"I can picture the hallway where it happened, his hands around my neck choking me," she says. "Then he put his hands down my pants... It was painful. I told him to stop."

Moon says the five-hour attack took place outside of school in a secluded cottage on England's South Coast, rented for the weekend by a friend at the elite girls' boarding school she attended: Benenden. She was 15 then.

Boys from the two all-male schools the girls often socialized with -- Eton and Tonbridge -- were also there and saw her fight her aggressor off multiple times. Yet no one intervened, she says.

"We're privileged kids, but despite all the money that goes on the maths and lacrosse lessons, not a penny is spent in these schools teaching students about their right to be safe from this type of behavior, which is a disgrace," Moon remembers of her school days.

"And it's important we talk about this because these are the men who will in some cases go on to run the country," she adds.

Eton, which has educated numerous British prime ministers, including the incumbent Boris Johnson, and Princes William and Harry, told CNN by email that it does run workshops on healthy relationships, teaching pupils about consent. It said it always takes specific allegations extremely seriously, supporting those affected and working with the police and children's services, when appropriate.

"Safeguarding the welfare of young people is our highest priority," said Eton in a statement. "All involved in education have a responsibility to recognize that we can and must do more so as to effect meaningful and sustained change, for the benefit of all young people."

The school did not address CNN's specific questions about what Zan Moon has alleged.

'Rape Culture'

Like a growing number of young women in the UK, Moon is speaking out about her experiences -- and soliciting the memories of others -- to smash the stigma of discussing a "rape culture" which they say is rife in schools.

What has burst forth is a chorus of anger, drowning out the deafening silence that previously surrounded the issue of sexual violence among school children.

After compiling a 15-page dossier of alleged incidents at multiple institutions, Moon wrote an open letter to the heads of Eton, Tonbridge and others, serving them notice on the "chauvinism" that she said "runs deep inside the UK's private boys schools." "It ends now," she wrote.

James Priory, the headmaster of Tonbridge, expressed "significant concern" after reading Moon's letter, saying in a statement that such behaviors had no place in his school. Tonbridge also said in a statement that it teaches consent to its pupils and refers incidents to the authorities when necessary.

"'We will be listening carefully to our students, staff and alumni, as well as to anyone who has contacted us directly from outside the School, in establishing what more we can do to ensure that sexual harassment and abuse are never accepted and that everyone will feel supported and able to come forward if they wish to," it said.

Moon's letter follows the initiative Everyone's Invited, a website that has garnered more than 13,000 testimonials detailing rape culture in British schools from current and former students.

They include accounts of 10-year-olds being catcalled, 12-year-olds being sexted, and disturbing allegations of rape -- all well below the UK's legal age of consent at 16 years old. The testimonies also include allegations of incidents at state schools and universities, highlighting the pervasive nature of harassment and violence against women in the UK -- an issue recently thrown into sharp relief by the killing of 33-year-old Londoner Sarah Everard, attacked while walking home from a friend's house.

"It's a lot wider than just the schools that have been named," says Everyone's Invited founder Soma Sara, a Londoner and former student of Wycombe Abbey girls' school. "There is a culture within our whole society of acceptance of sexual aggression and harassment. It's a culture that trivializes and normalized the worst behaviors and that can create an environment where sexual violence can exist and thrive."

A new helpline and action promised

On Thursday, the UK's Department for Education launched a new helpline to support potential victims of sexual harassment and abuse in educational settings. The government also announced an immediate review of safeguarding policies in state and independent schools. Meanwhile, London's Metropolitan Police are investigating several specific offences in relation to allegations on Everyone's Invited, and police are encouraging sexual assault survivors to speak out and seek support.

"We have subsequently received a number of reports of specific offences.

In addition, where schools have been named on this website, officers are making contact with those schools and offering specialist support for any potential victims of sexual assaults," wrote the Metropolitan Police in a press release.

"We understand the complex and varied reasons why many victim-survivors do not contact law enforcement, but I want to personally reassure anyone who needs our help that we are absolutely here for you," said The Met's lead for rape and sexual offences, Detective Superintendent Mel Laremore.

The anonymous nature of the posts shared on such platforms makes it hard to look into claims unless they are specific.

Individual schools have also launched investigations. Highgate School in north London -- where girls in Year 11 (aged 15/16) and above held a walkout in protest -- has commissioned an immediate external review of the sexual abuse and harassment allegations raised by student testimonies. It said in a statement:

"We are deeply shocked and horrified by the allegations that have recently come to light. The Highgate they describe runs entirely contrary to the values of our whole community ... We are truly sorry."

King's College School in Wimbledon, southwest London, also commissioned an independent review and said it will not accept any form of abuse or discrimination.

"The school has established a system to handle disclosures made by pupils, past or present and to offer support, and we urge anyone affected by these issues to come forward," it said.

The Everyone's Invited website has since stopped posting the names of schools alongside testimonies, but the debate continues. While hundreds of schools were named on the site, some current and former students, Like Moon -- have written open letters to headteachers, detailing their experiences of misogyny, abuse, and sexual violence.

One letter, penned by former Dulwich College student Samuel Schulenburg, accused the south London boys' school of being a "breeding ground for sexual predators." The letter was written to his former headmaster to raise awareness of problems at Dulwich, and detailed anonymous stories of sexual violence and harassment put forward by girls at James Allen's Girls School (JAGS), the sister school of Dulwich College.

Ribbons tied to the gates of James Allen's Girls' School, the sister school of Dulwich College.

In response to the open letter and anonymous allegations, Dulwich College headmaster Joe Spence said in a statement, "The behavior described is distressing and entirely unacceptable; we condemn it unreservedly."

"Whilst we cannot comment on anonymous testimonies, any specific and evidenced allegations will be addressed, and we will involve external authorities where appropriate," Spence added. "As a boys' school the first thing we must do is listen to what women and girls are telling us about their experiences and their concerns, but we also have a particular part to play, as educators of boys, in making a difference."

Victims asked to move schools

The Children's Commissioner, Rachel de Souza, said in a statement that "there is no excuse" for any school failing to follow safeguarding guidelines and offer victims support. Activists and women's campaigners say more preventative education is also needed in schools -- well before the onset of puberty.

"I think there's a lack of severity taken when disclosures are made. So often in schools, it will be brushed under the carpet," said Elizabeth Brailsford, herself a former headteacher now with Solace Women's Aid, a charity that supports survivors of sexual violence and conducts educational workshops in schools.

"Every time we go in to do a series of our sessions on healthy relationships, we'll get young people that come forward and tell us about experiences that they've had," Brailsford said. She added that it's "too common" for schools to suggest that girls who come forward with disclosures leave the school, "even though they're not the one that perpetrated the sexual assault."

Women's rights campaigners say that's little surprise in a country where sexual violence is now prosecuted at a much lower rate than in years gone by.

Rape prosecution rates dropped by 30% between 2019-2020 compared with the previous year, according to data from the Crown Prosecution Service (CPS).

More than 55,000 cases of rape were recorded in 2019-2020 but only 1.4% resulted in a charge or summons, the CPS data said.

Sexual assault, rape, and attempted sexual violence often goes unreported, and it's difficult to quantity experiences of rape culture more broadly. Fewer than 16% of victims in England and Wales report their experience of assault to the police, according to data from the Office for National Statistics (ONS). But among women aged 16 to 74, more than one in 20 (6.2%) have experienced rape or attempted rape, while 4.8% have experienced assault by penetration.

Meanwhile, 58% of girls aged 14 to 21 say they have been publicly sexually harassed in their learning environment, according to a new survey from Plan International, a global children's charity.

"I only realized fairly recently that most of the sexual relationships I had when I was younger were not what I would describe as consensual," says Moon.

"The whole top private school system is set up to protect the boy's prospects and the school's reputation. That's the priority," Moon said. "What happens to us girls doesn't matter to them."