The title of Potter Payper’s new mixtape references a letter he sent to his supporters back in 2017. He had been picked up on a drug supply charge and, in 2018, would begin serving a five-year sentence, stunting a decade spent building up a cult following with his raw road-rap freestyles and self-released mixtapes. In his letter, the Barking-born rapper promised to focus on music once he got out. True to his word, the 2020 Vision EP arrived days after his release last summer; the final instalment of his Training Day mixtape trilogy came in September. The latter reached No 3 in the album charts, and Potter was snapped up by hip-hop label Def Jam’s new UK imprint. Thanks for Waiting signals a new era. Previous Potter mixtapes have been largely solo affairs; here he runs an open studio. He spars with Digga D, Haile and Unknown T, who would have been kids when Potter, 30, first appeared, but now spearhead a scene that he watched grow from behind bars. He holds his own, flitting between old struggles and new riches. The bouncy, clout-condemning Rappers Lie mixes levity with pain; he effortlessly rides piano and rimshots on Gangsteritus. The album’s poppier strictures sometimes limit the freedom of his flow (such as on Catch Up, with M Huncho) ; managing that transition is his next challenge. At 18 tracks, Thanks for Waiting is bloated – but evidently Potter has a lot to get off his chest, and he’s done waiting.