Part of metal’s appeal is its terminal uncoolness. It can’t be co-opted, it isn’t ‘hip’, and it doesn’t easily translate to a mass audience. Sure, sometimes it has a dalliance with the mainstream, but there are always the hardcore contingent who take it to extremes, and they’re the ones who are still there when it slinks back to the darkness. Metal is, and always will be, outsider music. And if being uncool is what makes metal cool, then Judas Priest must be the coolest band on the planet. Their 1980 single ‘Breaking the Law’ remains their signature tune, and also…