Victoria Park

East London's oldest public park, opened in 1845 after local people petitioned parliament for somewhere to breathe. Still the People's Park to anyone who has been coming a while. Flat, enormous, and thick with dogs from about seven in the morning.

Hapoo counts the walk you were doing anyway

Read off your phone's motion sensor after the fact, so there is no start button and nothing running in your pocket. Characters turn up at real park gates across London, this one included.