Straight-backed at 70, Linton Kwesi Johnson wears the smart garb of a British Caribbean elder – trilby, cream jacket, West Indies maroon jumper and tie, grey trousers, blue socks and grey shoes. His voice has resonant, slow-rolling authority befitting Britain’s pioneer, premier dub poet. He folds his legs, but raises a lecturing finger. Though relatively relaxed and ready to laugh, he shows, in attitude as much as posture, a stern, iron backbone.