From clashing in front of crowds outside Lewisham McDeez with his crew The Square, to regular plays on the radio, Elf Kid is the South London MC making big moves in grime. His breakout hit Golden Boy got a world premiere from Zayn Lowe and its video — a love letter to Lewisham — was one of last year's most stylish. We caught up with the Blue Borough boy to talk sneakers, tracksuits and being business-minded.