In front of the Goldsmiths library at New Cross, a familiar scene is brewing. A stocky young man revs up in front of the low wall. His comrades flank him from a distance, poised to shoot with a GoPro and an iPhone for backup. ‘Let’s go, Verky!’ yells one. In response, the young man starts running. He vaults over the wall with ease, circles around a neighbouring tree, ricochets off the bus stop, does a somersault in the air and sticks a graceful landing. Two passersby watch in mild fascination, n