There is blood on my face, but not all of it is mine. I'm writing this from the UCL occupation, where injured students and schoolchildren keep drifting in in ones and twos, dazed and bruised, looking for medical attention and a safe space to sit down. It's a little like a field hospital, apart from the people checking Twitter for updates on the demonstration I've just returned from, where 30,000 young people marched to Whitehall, got stopped, and surged through police lines into Parliament Square.

They came to protest against the tuition fees bill that was hauled through the House yesterday by a fractured and divided coalition government. They believe that parliamentary democracy has failed them, that the state has set its face against them. When they arrived at Parliament Square, they found themselves facing a solid wall of metal cages guarded by armed police.

Then the crackdown began and it was worse than we feared. As I write, a young man called Alfie is in hospital after a "police beating" that left him bleeding into his brain, and all the press can talk about is the fact that a middle-aged couple -- one of whom happens to be the heir to the throne -- escaped entirely uninjured from some minor damage done to their motorcade. The government will no doubt be able to find the money to repair the royal Rolls Royce, but yesterday it declared itself unable to afford to repair the damage done to these young people's future.

A kind father of one of the protesters has brought in a vat of soup; I'm slurping it and trying to stop my hands from shaking. Two hours ago I was staring into the hooves of a charging police horse before a cop grabbed me by the neck and tossed me back into a screaming crowd of children, and the adrenaline hasn't worn off.

Behind me, on huge makeshift screens showing the rolling news, reporters and talking heads are praising the police and condemning the actions of young protesters as "an insult to democracy". But when you see children stumbling and bleeding from baton wounds and reeling from horse charges underneath the glowering auspices of former prime ministers carved in bronze, when you see police medics stretchering an unconscious girl away from the grass in front of Westminster Abbey, her pale head swaddled in bloody bandages and hanging at a nauseating angle, you have to ask to whom the real insult has been delivered.

What I saw a month ago at Millbank was a generation of very young, very angry, very disenfranchised people realising that not doing as you're told, contrary to everything we've been informed, is actually a very effective way of making your voice heard when the parliamentary process has let you down. What I saw two weeks ago in the Whitehall kettle was those same young people learning that if you choose to step out of line you will be mercilessly held back and down by officers of the law who are quite prepared to batter kids into a bloody mess if they deem it necessary. What I saw today was something different, something bigger: no less than the democratic apparatus of the state breaking down entirely.

In parliament square, huge bonfires are burning as the young protesters in front of the horse lines at Westminster Abbey struggle against a new punishment tactic the police seem to have developed: crushing already kettled protesters back and down with riot shields. I find myself caught at the front of the line, squeezed and clamped between the twisting bodies of terrified kids, and my feet are swept from under me as the kids at the front tumble to the ground.

We all go down together, horses looming above us, baton blows still coming down on our heads and shoulders. I am genuinely afraid that I might be about to die, and begin to thumb in my parents' mobile numbers on my phone to send them a message of love.

On top of me, a pretty blonde seventeen-year-old is screaming, tears streaming down her battered face as she yells abuse at the police. The protesters begin to yell "shame on you!", but even in the heat of battle, these young people quickly remember what's really at stake in this movement. "We are fighting for your children!" they chant at the line of cops. "We are fighting for your jobs!"

I struggle to my feet just in time to see a young man in a wheelchair being batoned. Disabled Jody McIntyre is dragged screaming out of his wheelchair when the police realise that photos are being taken, and shunted behind the riot lines as an even younger man who was pushing the chair shrieks, "Where are you taking my brother?". Then, for some reason, the police decide to attack the empty wheelchair while Jody's brother is still steering it, perhaps in a cartoonish attempt to destroy the evidence.

The protest was never supposed to make it to Parliament Square. Desperate not to be kettled again, the young people who marched out of schools and workplaces and occupied universities all over the city veered away from several attempted containments and diverted into side streets, determined to make it to the seat of government to make their voices heard. When they got there they broke down the barriers surrounding the symbolic heart of the mother of parliaments and surged into the square for a huge party, dancing to dubstep, the soundtrack of this organic youth revolution. Besides the apocalyptic bonfires and thudding drums in the containment area, dazed and battered protesters share out rolling tobacco and carby snacks. "Hey, look at this!" giggles one girl, "I'm eating Kettle Chips in a kettle!"

This time, unlike the first three big days of action, there certainly is violence on both sides. While some students came prepared, even bringing a portable tea-and-cake tent complete with minature pagoda to the kettle, others have brought sticks and paint bombs to hurl at the police. In the face of fellow protesters screaming at them not to "give the coppers a reason to hit us", stones are thrown at horses as angry young people try to deter the animals from advancing.

Many of these young people come from extremely deprived backgrounds, from communities where violence is a routine way of gaining respect and status. They have grown up learning that the only sure route out of a lifetime of poverty and violence is education -- and now that education has been made inaccessible for many of them. Meanwhile, when children deface the statue of a racist, imperialist prime minister who ordered the military to march on protesting miners, the press calls it violence. When children are left bleeding into their brains after being attacked by the police, the press calls it legitimate force.

Hanging off some traffic lights, my back aching from the crush, I have the best view in the house of this "legitimate force" being enacted, as a line of riot cops forms a solid carapace of beetlish menace and marches forward into the crowd, raining down baton blows. Then the protesters cluster together and push back, and my mouth falls open as I see the police retreat into formation. I am suddenly reminded of school history lessons about Roman battle tactics, and indeed, looking down at my hands as I type, I notice that they are covered in blue paint and streaked with blood. It's clear who the Anglo Saxon warriors are in this equation.

When I drop down from the traffic lights, my arms and back aching from being crushed earlier, I find myself at the front of the riot line, being shoved between two shields. Fighting for breath, I am shoved roughly through the line by two police officers; twisting my neck, I see a young woman in a white bobble hat pinned between the shields and the crowd, screaming as the batons come down on her head once, twice, and her spectacles are wrenched from her face. Her friend is shrieking, "please don't crush us, we can't move back, there's no room!" She is pushed through the line, too, and the police refuse to find her a medic. "I've never been on a protest before, I'm a completely peaceful person -- I'm doing my PhD on Virginia Woolf," she pants, her face streaked with tears of anger. "My name is Helen Tyson, and I'm disgusted, utterly disgusted by the police today." We cannot speak any more, because a huge officer in full armour taps me on the shoulder and orders me to leave. When I explain that I am a member of the press and I'd like to observe what's happening, he tells me that this is a "sterile area", and I am dragged away by my arms and legs and dumped by Horse Guards Parade.

A sterile area: that's what the heart of our democracy has become, a searing wound of rage and retribution cauterised by armoured and merciless agents of the state.

Things fall apart. Something fundamental has changed in the relationship between state and citizen over the past month. Increased police violence will not stop our democracy disintegrating: before it's too late, before more children are brutalised at the heart of what once pretended to be a representative democracy, this government needs to consider its position.