Don't even think about reading this if you're new to Herron's Slow Horses series: too many plot trails, too many character arcs are carried forward from what has gone before. But for devotees, there are intriguing developments with PJ back on the scene, and as scarily obnoxious and self-serving as ever.

I don't want to give away even hints of spoilers but will say that there are some painful deaths, a vast coincidence that ties the various plot strands together, and far too long spent chasing around snowy Wales for my taste with quick-switch cuts between the various hunters and huntees.

Still, Herron's writing is just so sharp, snarky and blackly funny that I can forgive much; and his handle on realpolitik is spot-on as usual. And with a sudden revelation as the end, this series has bags more mileage - thankfully.