BRENDAN O'NEILL: Barbaric and inhumane. This internet trolling of Kate betrays a moral rot in society that MUST be rooted out

The online persecution of the Princess of Wales is one of the ugliest spectacles of our time. For months, an unholy alliance of crackpot conspiracy theorists have been using the internet to hound Kate and her young family.

This motley mob of anti-Kate trolls have been pumping out cruel speculation about her health and whereabouts. They have swarmed social media sites to push feverish, flagrantly fact-free theories about Her Royal Highness.

Is she really ill? Or is she in hiding? Perhaps she has abandoned Palace life following a falling-out with William.

Kate felt obliged to explain, releasing a video message revealing that she had been diagnosed with cancer. The Princess was a picture of grace and self-control

All rubbish. All stupid. All adding to the Waleses' burden.

There are other, viler, theories, often compounded by inaccurate stories in the mainstream foreign Press which doesn't have the decorum of the British media. Indeed, Spanish papers last week published flawed, unfounded reports.

Amid reports that Kate is 'considering' making balcony appearance at Saturday's Trooping the Colour, the cruelty of such misinformation is mind-blowing.

Who in their right mind would spend their days promoting hurtful rumours about a young mother diagnosed with cancer? Why would anyone make a hobby out of taunting a poorly mum whose only 'crime' is to take time out to convalesce from surgery and illness?

The fact is that the trolling of Kate betrays a moral rot. It's been going on since January, when it was announced that she was undergoing abdominal surgery.

Crucially, that news should have meant that her medical privacy would be respected. But the abuse has continued ever since, summed up, in particular, by the demented reaction to a charming picture of Kate and her children that was released to mark Mother's Day.

Kate's admission that she had tweaked the image in a minor way – something everyone does in the selfie era – was seized upon as proof, yes proof (!), by poundshop Columbos that the royals are hiding something.

To everyone's shame, Kate felt obliged to explain, releasing a video message revealing that she had been diagnosed with cancer.

The Princess was a picture of grace and self-control. It was a 'huge shock', she said calmly, but 'I am well and getting stronger every day'. Yet for all her stoicism, there was something sad about the video, which felt almost like a hostage statement – made under pressure, not from gun-wielding terrorists, but demented trolls.

There was a medieval feel, as if a woman had been dragged into the public square, shamed by an unforgiving mob into professing her sickness to weird, wide-eyed onlookers. A forced conversion to the cult of self-revelation.

Even the video, inevitably, was held up by a twisted minority as proof that something was awry. 'It's not really her,' said loons online. 'It's AI. It's a body double...'

The trolling of Kate is more than just another online feeding frenzy. For years, social media platforms have amplified the potential for bullying, abuse and sexual exploitation. But her treatment raises pressing questions about society.

It is reported that Prince William is at his wits' end over the hounding of his wife

For a start, it shines a harsh light on a scale of internet addiction that's dragging us ever further into a vortex of anti-social and immoral behaviour.

If we witnessed such appalling behaviour in a pub, for example, we'd react to stop it. Why, then, do we tolerate such bullying on the net? It benefits no one to pretend that vile trolls are just a modern version of bar-room boors. Trolling is not an extension of the human experience – it's a rejection of it.

The internet coaxes us away from the institutions and social connections which for millennia have helped to keep us sane and good.

Family, friends, real-life socialising and all the other habits of togetherness developed over centuries – these things kept us grounded. Now, with just a flickering screen for company, people are left to their own lonely devices in a virtual world of non-stop nonsense. The Princess's treatment exposes the threat posed by internet culture to civilisation itself. Weirdos online can be seen and heard by thousands, perhaps millions. By the power of their fingers alone, they can disseminate their bitter drivel to the world.

And yet these 'broadcasters' are free of the rules and etiquette that govern books, television and newspapers. The Kate-haters can say whatever they want, whenever they want, with no consequences. And all under the cloak of anonymity.

As a society, we urgently need to tackle this evil. I'm convinced that if everyone had to prove who they are before they could post on social media, trolling would evaporate overnight.

Kate became a target of a shocking stream of malevolence that drips hourly from the internet

Of course, it's not straightforward. We are often told that online anonymity is essential to free speech. That without this cloak of invisibility, people would not feel confident to blow the whistle on government corruption or to stand up to ruthless rulers.

That might very well be true, in part at least. Yet there is no denying that in many societies, including ours, the use of false identities is being exploited for the purposes of bullying and harassment. Anonymity has become the fetid trench from which anti-social cowards shoot their invective at public figures, degrading public life for all of us. It would be a good start if the billionaires of Silicon Valley – and our own political classes – would at least address the problem, acknowledge the potentially catastrophic downsides of allowing people to hide behind a mask.

We may live in an era of 24/7 access to the inner lives of the famous. It's a world where it's normal to speak openly about mental struggles, for people to write memoirs on their emotional hardships, to post on social media about life's trials and tribulations.

In that context, when Kate did not comply with those behaviours and, instead, gracefully took time away from the public spotlight to deal with a very serious illness and look after her young family, she became a target of a shocking stream of malevolence that drips hourly from the internet.

The truth is that we should all be deeply concerned at the way the toxic, anti-social thrust of the Internet Age chips away at civilised values and at the barbaric fad for anonymous hectoring. If we fail to put a stop to this, it won't only be bad for the Waleses – it will be bad for Britain itself.

It is reported that Prince William is at his wits' end over the hounding of his wife. As well he might be. But he should remember that there's a groundswell of decent, normal people out there who are on their side.