The ninth novel in the Slough House series, this tale of IRA infiltration is a perfect mix of one-liners, plot twists and real-world-tinged intrigueTrigger warning: the new Slough House novel shares its name, I assume accidentally, with a particularly bleak soft-play centre on London’s North Circular Road in which sticky under-fives circulate through an infernal apparatus wailing and stabbing each other with plastic forks while the grownups sit at plastic tables drinking horrible coffee and waiting for death. Just a glimpse at the dust jacket sent me back a decade to that environment of grubbiness, boredom and mild peril. It’s not that big a leap, mind. There’s something of the knockabout quality of a soft-play centre in Mick Herron’s fictional world: all fun and games until someone loses an eye.That said, as far as I know, none of the injuries in the real-world Clown Town will have been occasioned by the victim being held down so the front wheel of a Land Rover Defender c...