John Le Carre’s mantle is a tough one to don. Every few years a new pretender is crowned by critics and mostly I’ve admired them without spotting more than occasional glimpses of greatness. In the last decade, I’ve become less and less inclined to dwell in the spy thriller genre, just for that reason. Well, more fool me, because Mick Herron, lauded by Val McDermid as “the John le Carré of our generation,” is the real deal that has somehow snuck past my gaze. Over a decade and a half, he has produced four novels in the Zoe Boehm series and now five in the highly acclaimed, award-winning Slough House series (with one on the way next year). A friend recommended I tackle the first Slough House book, Slow Horses, in audiobook form, and I’m currently rivetted by that, but in the meantime Herron has released his second Slough House novella, The Drop, so I grabbed that and devoured its 112 pages in a single sitting. Whilst the full pricing of The Drop means I can’t recommend it as an entrée into Herron’s catalogue, if you’re a Herron fan, by all means read it, for it contains what I’m realizes are his trademark attributes: a serpentine plot cunningly divulged; larger-than-life, all-too-humanly-cynical characters, stunning set-piece scenes; a coruscating wit; and, amazingly enough, a humane sense of outrage and compassion underneath the theatrics. It’s that last achievement, an almost miraculous undertone of morality, that imparts the greatness of Le Carre onto the shoulders of Mick Herron.