If you look closely at this picture, you'll notice some things hanging from the tree in the left foreground. Some bags, to be precise.
These bags belong to the people selling the Big Issue magazine at the traffic lights. They spend hours at a time at the side of the road, peddling their publication, and this is the most convenient spot for them to store their belongings, I guess.
I rather liked the idea of capturing the evidence of their presence, without actually taking a photo of the people themselves.