If hip-hop is the folk music of the post-industrial age, then Slick Rick is it's Woody Guthrie. Born in London and raised in the Bronx, the rapper essentially invented the smooth-talking storytelling style that has inspired everyone from De La Soul and Digital Underground to Snoop Dogg and Kendrick Lamar. His witty, thoughtful verses broadened the scope of hip-hop with stories about treating your mother with respect and catching your girlfriend cheating with the postman, alongside hard-hitting lyrics about social deprivation and immigration. Eminem described himself as "a product of Slick Rick", Jay-Z likened the star to Matisse, and Questlove called his voice "the most beautiful thing to happen to hip-hop culture". Amy Winehouse immortalised him in the song Me and Mr Jones. On Thursday, he will receive a lifetime achievement prize at the Mobo Awards after performing a career-spanning set with Estelle. Speaking from his home in New York, Slick Rick is remarkably humble about the honour.…