A boy was murdered near where I live recently. The spot where he fell has become a temporary shrine with flowers and graffiti. On the weekend a group of kids had started hanging out there (they hadn't been there during the week), there were talking nosily and shouting out to passers-by while another kid aimlessly (and dangerously) cycled around the streets surrounding it.
I realised that the kid on the cycle was spotting and the group at the spot were showing themselves on their ground.
There was a surreal quality to it. There in the middle of a regular Saturday of building, trading and shopping. There on the streets with their Jaguars and Aston Martins. There was a boy caught up in his own drama of patrolling the streets where one of his group had fallen.
The lines of the territory are invisible to people like me, as the article I linked to says the area consists of people of all different classes and wealth overlapping in the same metres of territory. The Bemerton estate at the centre of it, a mess ever since I've been here.
This kind of violence is mostly class-based and isolated geographically. I might get robbed but I'm isolated from the threat of being killed because of who I am and where I spend my time.
The article is wrong at least in talking about the reconstruction of Kings Cross. Caledonia Road has been that way ever since it was created to connect Kings Cross and Archway, initially through marshy farmland. To the east the planned streets, to the west the land between the road and the railway, the road itself evolving into the necessary neutral zone between the two where shared needs meet.
London, and Islington in particular, feels unique in having these social layers sharing the same geography, every other city I've ever been to links boundaries to geography, streets serve as borders. Here in a crowded city we're all creating our own psychogeography in the same physical space.