Joe Country is the sixth book in the Slough House series by prize-winning British author, Mick Herron. Standing at the graveside next to his mother, River Cartwright is paying his final respects to his beloved grandfather, David. The solemnity of the occasion is shattered when he spots the unwelcome face of the man he would probably most want to kill, and gives chase.

Back at Slough House, Jackson Lamb does not hesitate to set his charges to work on finding out when Frank Harkness arrived in the country, with whom, and where he might be headed. Because his presence at the funeral cannot have been benign, and this is the man responsible for the death of at least one of his operatives. And they may be slow horses, but they're his slow horses, and Lamb will not tolerate trespass on his territory.

Not participating, however, are: Louisa Guy, who is surprised to find herself taking leave to track down a teenaged boy as a favour to a certain widow; and Lech Wicinski, Slough House’s newest member. Readers of Herron’s novella, The Drop will be aware of the alleged misdeed that has landed him here, and is causing the others to keep their distance, despite his protestations of innocence.

Events soon have several of them racing off to Wales despite the predicted heavy snowfall. This leads to some rather radical driving, reluctant huddling together for warmth, encounters with nasty killers, and an exploding barn. An earlobe is bitten off, toes are shot at and some home truths are told.

As always, Lamb is the master of obnoxious insult (in fact, it seems to be rubbing off on his crew: Emma Flyte remarks “I sometimes wonder if Lamb gives you all lessons in smart-arsery”); Roddy Ho continues to remain deluded as to his own importance; Catherine Standish remains a stalwart of comfort and guidance; J.K. Coe maintains his silence; and Shirley Dander, despite passing her anger management course, still barely controls her simmering, sometimes seething, anger.

Again, the dialogue provides plenty of (often quite black) humour and, while this one will incite plenty of guffaws rather than giggles, dedicated readers know that Herron shows his regular characters no mercy: from the first pages it is apparent that some of their number will probably be dead by the last page. The realisation of this by their colleagues is a sober moment that may well cause a lump in the throat.

Di Taverner, now First Desk, apparently has plans for Slough House and the final page will have fans wondering what fate Herron intends for our favourite slow horses. Excellent British spy fiction, as always.