Behind Tom Templar’s shoulder as we talk over video call is a poster for The Wicker Man, the 1973 cult folk-horror film set on a remote Scottish island, whose sunniness conceals – inevitably – a dark secret. It’s fitting, because Templar is the singer of Green Lung, the breakout British metal band who immerse themselves in British mythology. The forthcoming Necropolitan, their fourth album devoted to the folklore of the isles, takes its inspiration from the “Magnificent Seven” London cemeteries built in the 1830s and 40s, and from the Necropolis railway, which transported the dead out of the city. No...