I live two blocks away from the temporary detention centre that the Integrated Security Unit has set up on the east side of Toronto for the G20 summit. It’s normally a film studio, but is now fortified with an additional security fence and guarded by police officers. You can see it in this video, made by an alternative media group last Thursday, two days before the summit began. The journalists are approached by two plain-clothes police officers who take their details and then refer them to a police spokesman who insists that the detention centre is at an undisclosed location while gesturing towards the film studio.

There wasn’t much action in this area of Toronto on Saturday as the world leaders were arriving. The protests were taking place downtown. After demonstrators were turned back from the security fence around the G20 site, police cars were set on fire and shop windows smashed. Government officials and the media agreed however that the majority of protesters were peaceful and that the destruction was being caused by ‘anarchic elements’ using ‘black bloc’ tactics.

By Sunday morning more than 500 people had been arrested and were being processed through the detention centre. A group of protesters had arrived to chant outside. I was watching the England-Germany game when I heard shots being fired. I turned on the radio: a frantic CBC reporter on the move from the scene was abruptly cut away from for a scheduled programme about the idylls of small-town Canada.

I went out to see what was going on. Riot police had driven the protesters up a side street away from the detention centre. The demonstrators had spilled out at the intersection at the top of the street where the riot police now stood three-deep. Police cars and paddy vans lurked around corners.

The locals meanwhile went on about their business, walking their dogs or doing their Sunday shopping. A coffee shop terrace fifteen feet from the riot police was full of people, who only occasionally glanced up from their books or conversations.

What I had failed to see for myself I saw later on the internet and TV. Images of the police using muzzle blasts to disperse the protesters – the shots that I had heard earlier – were quickly up on local news websites. There was footage of riot police charging and trampling a group of demonstrators singing the national anthem. The protest ended with the kettling of hundreds of people, protesters but also passers-by, for three hours in the rain while police pulled out, photographed and arrested people one by one. Several people said they had tried to explain that they were simply out for dinner or had been waiting for a streetcar, only to be met with stony silence. At 9.45 p.m., as media and online pressure mounted, the police stood down and people walked or ran away.

The total number of arrests stands at over 850. At least 150 people are still in custody at the detention centre this morning. The protests are scheduled to continue today, even though most of the G20 leaders left yesterday evening. Toronto’s police chief is expecting further arrests.