Each week in Manchester, in an undisclosed location, a similar scene unfolds. On this particular day, in early September, it goes like this: A few people set up a card table in a shady spot. In front of the table they place a few plastic buckets.
Soon, a woman approaches holding a shopping bag. Inside are several used syringes. She empties the bag into one of the buckets, chats with the people manning the table, then refills the bag with a few boxes of clean syringes.