“I want to die.” Rob and Claire Johnson’s daughter was screaming, hysterical and inconsolable.

Ten-year-old Emily told them a boy at school had slapped her, hard, across the face: “I want to die. Nobody believes me. He’s hitting me and nobody believes me.”

“We didn’t know what to do,” Rob tells me, his voice echoing the helplessness and frustration he felt. “Hearing her say those words – what parent wants to hear that from their 10-year-old daughter?”

When Claire tried to speak to the school about the incident, they quickly dismissed it as “a misunderstanding”, telling her: “Everyone’s happy now.” But Emily was far from happy. Over the subsequent two weeks, she gradually opened up to her parents with the help of her GP. Slowly, she described how the boy in question had sexually harassed and assaulted her over the past 10 months.

It emerged that another child had made a detailed report to the school after witnessing the boy intimidating and assaulting Emily. The classmate had told staff it happened in a corner of the playground known as the “sex corner”, where the boy had forced Emily against a wall, pinning her hands on either side of her as he gyrated and rubbed his body against hers. Emily closed her eyes and started crying.

But school staff hadn’t considered the incident serious enough to contact Emily’s parents. In the intervening months, the Johnsons watched as Emily became angry and withdrawn, and started self-harming. They couldn’t understand what was wrong.

Then, everything began to fall into place.

Over the previous months, the boy had asked Emily for oral sex and demanded to see her vagina, details that emerged only when her sister decided to break her silence, telling Rob and Claire: “He asked her for a blowie.” Claire’s voice is full of emotion as she continues: “She didn’t know what it meant. She said: ‘I think it means hard sex.’”

When sexual harassment and assault starts at such a young age, it can be hugely confusing for children.

When Emily’s distraught parents asked why she hadn’t told them what was happening, she admitted that she had been terrified they would be angry with her, adding: “Because I thought I might be pregnant.”

That Emily faced such a terrifying ordeal alone is an indictment of an education system that sees children experiencing sexual harassment and abuse in school, but does not provide them with the tools to understand what it is or reach out for support.

Emily is far from alone. According to BBC research, 5,500 sexual offences were reported to police as having taken place in UK schools over a three-year period to July 2015, including 600 rapes. And a recent women and equalities select committee (WESC) report highlighted widespread sexual harassment and abuse of girls at school.

Faced with the horrifying realisation of what their daughter had experienced, the Johnsons set out to get to the bottom of the problem, but encountered serious resistance. When they wrote a letter about the abuse, Rob says, the school was keen to: “Reduce this to something it wasn’t … It seemed very much that the main focus was to safeguard the school’s reputation rather than safeguard the children.”

Rob was devastated, both by the impact this could have on his own daughter, and on other potential victims. “For me personally, the hardest thing has been that they haven’t wanted to acknowledge there’s even been an allegation of sexual abuse or sexual assault. The terminology is really important in these things ... you’ve already told a 10-year-old girl: ‘If you’re assaulted don’t bother coming forward because we don’t believe you.’”

Over the next five weeks, the Johnsons reached out to everybody they could think of for help. First they tried the school’s board of governors, but were shocked when the safeguarding deputy suggested “restorative justice” (where the victim and abuser would discuss the assault face to face), which they felt was totally inappropriate. Next, they contacted multiple GPs, who rang the school independently after examining Emily to verify that they felt she had been a victim of sexual abuse. Then the Johnsons contacted the local council and police, neither of whom were able to offer much support, in part due to the fact that the perpetrator had been aged nine (and therefore below the age of criminal responsibility) at the time of the abuse. Eventually, they turned to their local MP and to charities such as the NSPCC and ChildLine, taking an advocate to school with them for support. It was only after over a month of determined effort that they forced the school to acknowledge what had really happened.

Despite Emily’s ordeal, Rob doesn’t solely blame the school for what happened:

“It’s very easy to blame the school, and say this is all their fault [but] I think they were just unequipped to deal with this. If there aren’t any guidelines you’re completely stumped … There need to be concrete guidelines about how we safeguard children, boys and girls, about sexual assault, exactly what procedures we need to follow and they need to be uniform and sent out to every school. And that can only come from the government.”

The education secretary, Justine Greening, on the Andrew Marr Show. Photograph: BBC/PA

Earlier this year, lawyers wrote to the education secretary, Justine Greening, to warn her that the lack of clear guidance telling schools what they should do when rapes and sexual assaults are reported could leave her open to legal action. At the time, the Department for Education said the Keeping Children Safe in Education guidance was last updated in 2015, but was kept under regular review. “Schools should be safe places and they have a duty to protect all pupils and listen to any concerns. We issue regularly updated safeguarding guidance – which includes advice on peer-on-peer abuse – to protect pupils’ welfare.”

Under questioning by the WESC this year, the schools minister, Nick Gibb, said official guidelines needed to be clear that abusers could not return to classes alongside people they attacked, and pledged that the government would shortly launch a consultation to make the required changes.

Sarah Green, co-director of the End Violence Against Women Coalition, says the promised new guidelines “frankly can’t come soon enough”.

“We know that many schools currently fail terribly when girls and their families report sexual assaults – because heads, teachers and governors do not have adequate training or guidance in this area. Girls have been told to just put up with this behaviour for too long.”

The Johnsons are relieved that the school has finally admitted, and recorded, the reality of the sexually abusive behaviour Emily experienced, and have put measures in place that will keep the boy away from her at all times. But the solution isn’t perfect. Claire is unhappy that it is her daughter who is removed from certain lessons and activities. “Why [is she] suffering consequences when [she has] done nothing wrong?” she asks.

Both parents believe it should not have taken such a gargantuan effort on their part to achieve this outcome. Other parents, they fear, may not be so tenacious in similar circumstances. Rob says: “We know of other parents who are moving their kids and I can only imagine … I dread to think if you didn’t know where to go it must be awful.”

Claire wishes the school would do more to take the problem seriously: “There could be other girls in the same situation. They know that … But it’s all about the reputation of the school. Everything’s covered up. Nothing’s transparent.”

Emily’s story is just one among many of sexual violence in schools, with confusion and inconsistency abounding in the treatment of victims and survivors. Claire says: “You hear about young girls being raped and sexually abused in other countries, but no, it’s happening in our schools. It’s happening to children here and nothing’s being done.”

Names have been changed.