Dead Lions, by Mick Herron

A relict of the Berlin Zoo of the 80s, former minor spy asset Dickie Bow is found dead on a regional bus, with mystery surrounding the whys and wherefores. Is a long-dormant Russian sleeper cell awake, or is it an elaborate ruse to fool the intelligence services and divert their resources? And can the Slow Horses save the day or will they completely balls it up? Ambition rules decisions made at all levels of MI5. Those in the inner sanctum at Regents’ Park want to climb the ranks. Those in the outer reaches of Slough House, the screw-up ‘slow horses’, are desperate to make it back to the main game. A sequel to Slow Horses, this tight, tense and tart tale keeps the outcome in doubt until the end. Some relationships among the Slough House crew are strengthened and some are lost as the ill-assorted team gropes its way to the truth, and makes progress in operating as a team.