Teachers say they do not feel equipped to deal with peer-on-peer sexual abuse because they have had no training.
More than 1,500 UK teachers replied to a questionnaire from BBC Radio 4’s File on 4 and teachers’ union the NASUWT.
More than half said they did not think adequate procedures were in place in their schools to deal with abuse.
Many are also unsure how to deliver elements of a new sex-and-relationships curriculum, which the government says third parties might now help with.
In England, the Department for Education has introduced a compulsory Sex and Relationships Education (RSE) curriculum in all schools, focusing on relationships in primary schools and sex and relationships in secondaries.
It has also asked Ofsted to review peer-on-peer safeguarding procedures.
Of the teachers surveyed, almost a third said they had witnessed peer-on-peer sexual harassment or abuse and almost one in 10 said they saw it on a weekly basis.
The debate about a culture of sexual abuse at schools has escalated in recent months after a website set up for victims to post their experiences anonymously gained more than 16,000 posts – some from children as young as nine.
The Everyone’s Invited website publishes anonymous allegations which refer mostly to sexual harassment carried out against young women by young men at their school or university.
The government has now launched a dedicated hotline with the NSPCC for young people who feel they have been harassed and abused.
Since the helpline launched at the beginning of April, it has received more than 350 calls, and 65 referrals have been made to agencies including social services and the police.
The new RSE curriculum in England was introduced in September 2020.
Andrew Fellows, associate head of policy at child-protection charity the NSPCC, says that while the new lessons are a positive development, schools have not been given the support and guidance to deliver the new curriculum effectively.
“Coercive control, sexual consent, healthy relationships, online safety, pornography – that’s all in there.
“But what schools haven’t been given is the guidance and the support to cover that and to deliver that in a way that works for their students,” he said.
Flora Cooper, head teacher of Crowmarsh Primary School in Oxfordshire, where staff have just started to teach the new RSE lessons, said: “In terms of external training, we’ve not had any.
“We actually haven’t seen much being offered in terms of training and it is absolutely in the training – that’s what is essential, which we don’t have.
“Until the teachers are confident with the delivery of the content, then I don’t think any of them will be confident and fully teaching the children the full curriculum. It feels as though we are on our own.”
Ofsted is currently conducting a review of safeguarding policies and practices relating to sexual abuse in state and independent schools and colleges.
It was ordered by the government after thousands of young people – mostly girls and young women – contacted the Everyone’s Invited website.
Children’s Minister Vicky Ford said: “We’ve seen these enormously worrying and very shocking allegations that have come through the Everyone’s Invited site.
“One of the things that Ofsted will be looking at in this review is, are schools getting enough training and support? Do they need, for example, third parties to come in and train elements of that curriculum?”