At the edge of Parliament Square, Winston Churchill squints – hunched and impervious and marble – over the gothic heart of British democracy. Usually, his only company is the smoggy traffic and snapping tourists. But, for the past three months, he has been joined by another symbol, and another style of democracy.
In May, a smattering of tents was set up on this diesel-tinted green by citizens protesting against the war in Afghanistan. When I first saw them they were a mixture of students and activists and professors, voicing the conviction of 70 per cent of British people that the war is unwinnable and should end. One of them, Maria Gallasetgui, said: "We have a responsibility to stand up to what they're doing. It's immoral." She added: "We support the troops, that's why we want to bring them home. They" – she pointed to Parliament – "are the ones sending them to die."
They held up signs with pictures of maimed Afghan children, and waved them at the MPs as they walked to work. The MPs invariably looked down and away and they hurried through Parliament's iron gates.
These protesters are needed: despite the clear will of the British and American people, the war is being escalated, with an increase in slaughtered civilians of 23 per cent in the past year.
As I looked out over this rag-tag of tents and posters, I realised that they didn't only express the will of the people here – they were expressing the will of the people we are invading and bombing. The International Council on Security and Development just conducted an opinion poll of ordinary Afghans in Kandahar and Helmand, the places where these MPs have sent a surge of troops. Some 70 per cent of them stand with the tents and camp-fires, saying the military operation is harming them and should stop.
So just a few metres from where the Prime Minister lives, people sat on an open green barbecuing food and sharing drinks and calling for that Prime Minister to be indicted for war crimes. They had daily meetings where they shared out the responsibilities, while every 15 minutes, Big Ben bonged.
In that first month, I saw a group of Chinese tourists staring at the camp in disbelief.
"This would never be allowed in China," one of them said to me. "Not anywhere. Never mind at the centre of power. This is what democracy really means."
As the months went on, the tent city developed and mutated each time I visited. More protesters arrived, with a more eclectic range of grievances. A man appeared announcing he was starving himself because the courts wouldn't let him see his children: he hasn't eaten for more than 20 days.
After hearing there was free food, a group of homeless people set up camp there too. (They are a harbinger: Shelter says David Cameron's current policies will lead to a "disastrous" increase in the number of homeless people.) Suddenly, MPs didn't only have to stare at the victims of their war – they also had to stare at the victims of their failed social policies.
That's how it should be. They should see it every day – the faces of the Afghan children we have caused the deaths of, and the faces of the mentally ill people we have left to rot on the streets. I can't think of a healthier sign in a democracy – that we don't allow our problems to be cleansed, China-style, from the sight of the powerful, but leave them there, in full view, demanding to be dealt with.
Yes, a few parts of it smelled. But waging war in Afghanistan, against the will of the people there and the people here, smells a lot worse. Yes, there were a few crazy people in the tents. But none was as crazy as the belief that we can win a land war in Afghanistan now, after nine years, with the population rapidly turning against us and pleading for a peace and reconciliation process. Freedom is not an "eyesore", as the London Mayor Boris Johnson claimed: citizens pressuring their government for justice are the most luscious sight in the world.
Very early on Tuesday morning, the police came to force the protesters out, after Johnson got a court order. So now there is a clean, clear lawn again. Repressive governments the world over have seen footage of protesters being cleared from the lawn of the Mother of Parliaments, and chuckled with vindication.
MPs will look out on a reassuringly empty space as they stroll in to make their decisions, with the public will unvoiced. And Winston Churchill stands alone once more, save for the tourists, and the traffic, and the false silence of a displaced citizenry.
Follow Johann Hari on Twitter at twitter.com/johannhari101