Sexual harassment and abuse have become a "normal part of school life" for many pupils – and the government needs to start taking action, a group of MPs has warned.
Children of primary school age are learning about sex through hardcore porn, girls are regularly called "slut" and "bitch", and male pupils are often "rough with girls", the Commons women and equalities committee found.
Yet many schools are underreporting incidents and failing to take them seriously – so that sexual bullying is "too often accepted as the norm by both staff and students".
The committee's report, published on Tuesday, shines a light on the "shocking scale" of sexual harassment and sexual violence in schools across England. It warns that despite the weight of evidence, the government has "no coherent plan" to make sure schools tackle the issue.
It calls on ministers to use the new education bill to force every school to take action to prevent and respond to sexual harassment and violence – and says sex and relationships education (SRE) must be made compulsory in all schools.
More than 5,500 alleged sexual offences in UK schools, including 600 rapes, were reported to police between 2012 and 2015.
A YouGov poll in 2010 found that 29% of girls aged 16 to 18 experienced "unwanted sexual touching" at school, while 71% of pupils the same age heard sexual name-calling such as "slut" or "slag" towards girls several times a week.
And technology is exacerbating the problem. According to the NASUWT teaching union, girls are now regularly sending naked photos of themselves to boyfriends who forward the images to friends, and pupils are filming themselves masturbating and sharing the videos.
One Birmingham teacher told the committee: "I have had many young girls sobbing and humiliated in my office because partially naked images have gone viral.
"I have seen girls being threatened with those images going viral if they chose not to perform sexual acts on a boy. I have seen girls have to leave school because of the bullying they received from their naked images going viral."
The report warned that children's perceptions of sex and consent were also changing as a result of porn. A survey of 16- to 21-year-olds in 2014 found that almost a quarter were 12 or younger when they first saw porn online, and 7% were under 10.
One secondary school teacher told the MPs: "Pornography is easily available on mobiles and I have caught pupils watching it during break times."
Another said: "I have heard boys talk about certain porn stars and talk of their expectations for both girls and boys to have body shapes and proportions similar to what they view both from pornography and within the mass media. …
"I see the transformation of fresh-faced innocent year 7 girls who will try to be heavily sexualised by the time they reach year 10. I see these beautiful girls not understanding the option to say no."
The committee warned that current government guidance on teaching SRE was last updated 16 years ago and "has no reference to pornography". It said ministers should immediately update this to include teaching about porn in an "age-appropriate way".
Sexual harassment begins in primary school, MPs were told. The Brook sexual health service on the Wirral said it "definitely happens in primary school, especially in year 5 and 6", with pupils "lifting up skirts and pulling down pants" to the point where "some kids [are] scared to wear skirts".
A lunchtime supervisor at a middle school said she heard "constant sexual language", particularly from boys, among year 7 and 8 pupils in the playground.
"I have witnessed boys being very rough with girls. … The girls seem resigned to this treatment and when I have spoken to them about it they say none of the teachers listen. If I challenge the boys they seem to feel it is acceptable and just 'banter'."
One young person who gave evidence said: "I guess the thing that people would say they see the most, and we see as well, is slapping of bums and flicking of skirts. That is a common thing that people see in schools.
"There is also derogative term calling — calling women bitches and stuff like that – which is also a common thing that you see in school, on a daily basis really." Another young person said: "You see it every day in my school. I wouldn’t say it was appropriate, but it still happens."
Some pupils said their teachers didn't take sexual harassment seriously. "I don’t feel that it is really dealt with," one said. "If a teacher sees it, they will say, 'Oh, you shouldn’t say that,' and then it will be forgotten about really easily and no action will be taken about what happened."
One teacher admitted: "I have never received clear guidelines, from any of the schools that I have taught at, on how to deal with sexual harassment by pupils. I have reported incidents that have been quietly dealt with by the pastoral team, but I have never seen disciplinary consequences issued as a result of reporting such incidents."
The ATL teaching union warned of the deep-rooted consequences of sexual bullying, including girls being "even more unwilling to take risks even in academic areas" and being more self-conscious about their appearance "and not appearing too geeky".
The committee found that other impacts on victims included self-harm, isolation and withdrawal, substance use, sexually transmitted diseases, depression and anxiety, and lack of attendance at school.
Committee chair Maria Miller said: "It is difficult to explain why any school would allow girls to be subjected to sexual harassment and violent behaviour that has been outlawed in the adult workplace.
"The evidence shows it is undermining the confidence of young women. Failing to reinforce what is acceptable behaviour could well be fuelling the 'lad culture' that the government has already identified as a problem in colleges and universities.
"Despite this, the Department for Education and [schools watchdog] Ofsted have no coherent plan to ensure schools tackle the causes and consequences of sexual harassment and sexual violence."
The MPs called on the government to create a statutory obligation in the upcoming education bill for all schools, primary and secondary, to "develop a whole school approach to preventing and tackling sexual harassment and sexual violence".
"We also recommend that the Department for Education remind all school governors of their legal obligations to address sexual harassment and sexual violence in school," the report said.
A government spokesperson said: "Sexual assault of any kind is an offence and must always be reported to the police. Schools should be safe places and fortunately crime is rare but no young person should suffer harassment or violence.
"We trust teachers to promote a culture of tolerance in the classroom and to take swift action to deal with this sort of behaviour. This is backed up by mandatory sex and relationship education in all maintained secondary schools. We will consider the recommendations of this report carefully."