It's probably the Cambridge Hash House Harriers or it could be the Cantabrigensis Hash House Harriers, or any other similar group in this area. They describe themselves as “drinkers with a running problem” - basically, a group of runners who run around chasing another runner like a pack of hounds pursuing a fox, hare or other small fluffy mammal. The 'hare' marks the route the 'hounds' have to follow by throwing down small piles of chalk or flour or other white powder. When they're not doing that, they drink beer.