SEVERAL years ago, Rape Crisis was kind enough to let me sit in on a workshop the organisation was running in secondary schools aimed at educating kids about sex and relationships. I sat quietly among a classroom of 14/15-year-old boys and girls, taking down my notes.

The workshop consisted of showing a variety of short videos depicting scenarios considered "grey areas". One of them was about rape. The film featured a teenage boy and girl, and the discussion afterwards was around whether or not the boy had raped the girl after a sexual encounter. My one piercing memory from that day was when the girls in the class began giving their verdicts. The girls, far more than the boys, thought that the girl in the video shouldn't have worn such a short skirt if she didn't want to have sex. She must have known what a boy would expect if she kissed him at a party in a short skirt. If she knew all of that and did it anyway, it must kind of be her fault, mustn't it?

I was stunned. I had been prepared for the young men in the room to hold outdated attitudes rooted in society's misogyny, but actually they were far less judgemental than I'd expected, and far less scathing than the girls. Many of the girls had little sympathy for the victim in the video.

At the time I probably brushed it off as a one-off, not representative or typical of how women think of each other. Sure, I'd gone to school, grown up with girls and I'd seen how ferociously they can behave towards one another, but surely that was just playground talk; when we grow up, we see things differently.

But evidence about social media behaviour which emerged last week has cast fresh light on the problem. If social media is an amplifier of how we behave towards one another in real life, the landscape for women is looking increasingly bleak.

Coinciding with the launch of a major new campaign, Reclaim The Internet, led by Yvette Cooper to tackle online abuse aimed at women on social media, Demos released research which showed that more than half of the abusers they'd identified over a three-week period of monitoring the problem were women.

Internationally, 80,000 individuals were the targets of misogynistic abuse during the three weeks during which Demos trawled social media for incidences of words such as "slut" and "whore", and more than 200,000 aggressive tweets were sent.

It's an odd statistic, but it's not actually that surprising. Some of the most ignorant, ill-informed social media posts I've ever seen about feminism have come from women, often repeating tired old lines rooted in deep sexism. I've seen women make the argument that, despite their statistically lower chances of progressing in their careers due to historic, institutional sexism, efforts to tackle those problems are tantamount to discrimination against men. I've been told that the lack of women at boardroom levels in a male-dominated sport like football can be explained away by a lack of women good enough for the job.

It has infuriated me, and it has made me angrier at those women than I've ever been at a man. I've argued with them, I've lost my temper, and, in hindsight, I really wish I hadn't. These peculiar attitudes in women are a reflection of how deeply ingrained discrimination against our gender has always been. We are so conditioned by it that we internalise it and use the language of this inequality as weapons against one another.

On social media it's there for all to see, and if the Reclaim The Internet campaign can begin altering the way women behave towards one another it could have a groundbreaking effect.

Campaigning feminism often projects an image of togetherness, solidarity and mutual support, but that message doesn't resonate with those who've had a very different experience of treatment from other women, or, indeed, how they’ve behaved themselves. It may well be that the key to making a dent in the problem of online misogyny is about educating women, not men.

These are not just words on a screen, they are hurtful, damaging and dangerous attitudes, the kind that, when they pass in society with little challenge, lead journalists into classrooms to hear teenage girls blame each other when a man forces them to have sex. A fight as complex as this requires a truly united front. Let’s hope Reclaim The Internet delves further than soundbites and easy stereotypes in its efforts to tackle the problem.