OF all the terrifying headlines lately, the most shocking is that one in three girls in the UK has been sexually harassed in public while wearing school uniform.

The figures come from a report by children’s charity Plan International UK, which also found two-thirds of girls say they have experienced unwanted sexual attention in public.

A third of girls have been touched, groped or grabbed by men they don’t know. This kind of thing is so commonplace that many — some as young as eight — feel street harassment is “part of growing up”. How awful is that? Partly, the problem is that somewhere along the line, the idea that schoolgirls are “sexy” has become normalised, acceptable, even mainstream.

Yes, I know that the waters were somewhat muddied by the likes of Britney Spears in her Baby One More Time video and Gemma Arterton in her St Trinian’s films — both looking as sexy as heck in school uniform. And yes, I know a lot of girls look older than they are, and might even try to do so by wearing make-up, smoking or shortening their skirts on the way to and from school.

But let’s be really clear about this. — girls young enough to wear school uniform are children. And the idea of any man thinking it’s OK to wolf-whistle, chat up or give any kind of sexual attention to a girl in a uniform is not just seriously worrying. It should be a criminal offence.

By the way, I wonder what a similar survey of boys would find. Because the thought of women wolf-whistling schoolboys in the street is unimaginable, right? Parents of secondary school children need to give them some freedom to help them on the path to adulthood.

Often, that involves letting them walk unaccompanied to school. But the idea that doing that is exposing their child to the possibility of sexual harassment will be pretty distressing to any parent.

One of the saddest things about this report is how many of the girls interviewed thought this kind of behaviour is “normal”. One 18-year-old said she felt street harassment was part of the “bro culture” and her dad had told her: “You know what men are like.” What kind of advice is that for your daughter?

Another girl, aged 17, said: “It’s just become normal.” But the net result of behaviour like this is that it makes girls scared of walking the streets.

All too often, our response to such news is to try to protect girls by telling them not to look too provocative. But that just perpetuates the idea men “can’t help themselves” so it’s down to the girls, and the way they dress, to make sure they are left alone.

You can’t blame girls or women for men’s behaviour, no matter what the length of their skirt. But the difficult truth is that we know women do have to modify their behaviour, and the way they dress, to stop men from commenting on their appearance, harassing them or worse.

Perhaps what I am most shocked about is the young age at which this starts. One good thing is that these days, girls at secondary school have phones. They can record things that happen to them and report it. Also, Plan International UK is calling on bystanders to challenge harassment when they see it.

Certainly, if I was around someone wolf-whistling schoolgirls, I’d flip my lid. I would not be too scared to speak my mind and verbally intervene. I think my opening gambit would be: “How would you feel if that were your sister, granddaughter or daughter some old git was harassing?”

To any man reading this who thinks it’s OK to talk to schoolgirls like this, let me tell you some of these girls are terrified. It’s not funny or cute. It’s threatening. Lots of teen girls look older than they are but if you are confused and in doubt, here is a clue: The school uniform is a giveaway.

Any man who leers at a child in a uniform is nothing short of disturbed. And if they can’t stop themselves from doing so, the law needs to intervene.