Bob Vylan’s voice curdles with disdain. “We have kids living in poverty. We have a growing homeless population. We have a growing population using food banks, even though they are working full-time jobs. There are people living in conditions that are not fit for humans to live in. And we’re talking about the colour of a cross on a football shirt?” Vylan is a rapper, singer and guitarist of singular ferocity and intelligence. He’s also one half of the incendiary grime-punk duo Bob Vylan, alongside the drummer Bobbie Vylan. “Bobby” and “Bobbie” are not their real names, which they would...