Porn is under attack as never before. David Cameron says he will force internet providers to filter it out, while women's groups and campaigners against child abuse are arguing that it has a disastrous effect on young people's ideas about sex.

It's an old debate given new urgency by changes in the nature of porn and the way it is delivered; there's no doubt that porn has proliferated on the internet, where teenage boys can access it on their smartphones. It's also become much nastier, introducing us to hideous concepts such as "rape porn". That's one of the reasons, I think, why the consensus that something needs to be done is so much wider than before.

In the 1980s, it was more or less left to feminists to argue that some (not all) porn had negative effects; I always tried to make a distinction between sex which was enjoyed by both parties and sex-and-violence. These days the latter predominates and the idea that most internet porn has anything to do with women's sexual pleasure is laughable.

Download the new Independent Premium app Sharing the full story, not just the headlines

The porn industry targets men and increasingly boys, telling them that anal sex and blowjobs are a right, and the terrifying thing is that we don't have high-quality sex education in every school to counter it. We also have popular newspapers which portray women as submissive sex objects every single day, softening men up for the hard stuff they see on the internet.

I am sick of this, and so are a lot of other people. Publishing pictures of women's breasts in newspapers encourages the idea that we're just a collection of body parts, which is why I support the campaign to get rid of Page 3. I don't think half the population should be crudely displayed for the edification of the other half – and to sell newspapers. Nor do I think women should have to work in supermarkets where they have no choice but to see women's naked bodies on the covers of lads' mags; I love the fact that the feminist organisation Object has pointed out that this practice may be open to legal action under equality legislation. I'm pretty sure that the former editor of Loaded, Martin Daubney, wouldn't agree with me about that, but he's undergone a change of heart about porn. He's even made a film about it, which will be shown on Channel 4 tomorrow evening at 10pm.

I couldn't help cringing when I discovered the reason for his conversion; he has a four-year-old son and he's anxious about the effect porn might have on him as he gets older. It also worries me that the film, called Porn on the Brain, is so focused on the damage it does to men rather than girls and women. Daubney meets a 19-year-old man who accesses porn more than a dozen times a day; in a startling sequence, the young man suddenly pulls his car into a pub car park so he can nip into the men's toilets and masturbate.

The film is a mess, mixing laddish discussions of "wanking" with forays into neuroscience. But it does show scans comparing the brains of men aged 19 to 34 who consider their lives "controlled by porn" (sigh) with those of "ordinary people". The former display twice as much activity in response to pornographic images and the section of their brains that lights up is the same, apparently, as in people who have problems with drugs and alcohol. It's an interesting piece of research although the neuroscientist who carried it out thinks more work needs to be done to establish what's going on.

I worry that the notion of porn being addictive lets men off the hook. In much the same way, talking about boys who have been "sexually traumatised" by watching porn diverts attention from girls who are having to deal with demeaning and dangerous sexual demands from young men. I'm glad that Daubney argues for better sex and relationships education, but I'm uncomfortable with the notion that porn is suddenly a bad thing because it damages boys.

What we really need is a cultural shift against the idea that it's OK to exploit women in this way in newspapers, magazines and online. Feminist organisations made this point in their evidence to the Leveson Inquiry, arguing that the daily sexualisation of women in the media legitimises attitudes associated with discrimination and violence. Lord Justice Leveson seemed to agree, observing in his report that The Sun and the Daily Star have a tendency to "sexualise and demean" women and describing the Daily Sport as "hardly distinguishable" from the softer end of top-shelf porn. When a new regulator is set up, it's vital that it should be able to consider third-party complaints from women's groups, not just about sexist images in the popular press but the reporting of rape trials.

My sense is that the tide is finally turning against the routine sexualisation of women and girls. Why should we put up with being objectified every single day? The fight against internet porn is part of that struggle but it shouldn't be treated in isolation, as though it has nothing to do with a wider tolerance of sexism and abuse.

The old argument which characterised porn as central to free speech has been challenged by a more sophisticated understanding of its mostly dire impact on equality. The kind of porn which shows submissive women and dominant men – and that's just about all of it on the internet – distorts human relationships. It normalises brutality and the notion that women exist solely to do what men want. That isn't tolerable if you want to live in a society that treats both sexes with respect.

politicalblonde.co.uk; twitter.com/@polblonde