On January 7 this year, not even a month after the release of his second studio album, Heavy Is the Head, British MC and rapper Stormzy dropped a new, nonalbum track called “Disappointed”. Just two minutes long, “Disappointed” was one salvo in a furious exchange, played out in song, between Stormzy, 26, and another British MC, Wiley, 41 – the latter the first master, the former the heir apparent, of grime, the London music style that has threatened to go global for the better part of 20 years but never quite has. Until now perhaps. In the video for “Disappointed”, Stormzy stalks a moodily lit recording studio, spliff in one hand, mug of tea in the other. He warns the “old man” Wiley that he will come to regret their war for precedence. “I’m so big the only thing bigger than me last year was Brexit,” Stormzy spits.