Our book today is Real Tigers, Mick Herron’s return to Slough House, the forbidding location on the wrong side of the Thames from Regent’s Park, the sleek headquarters of M15. Slough House is where M15 sends its disgraced agents, the ones so tarnished as to be considered beyond rehabilitation. Thus sidelined into oblivion, these “slow horses” are supposed to be so crushed by mindless paperwork that they eventually retire themselves out of service altogether:

The rest hum with the repetitive churning of meaningless tasks; of work that’s been found for idle hands, and seemingly consists of the processing of reams of information, raw data barely distinguishable from a mess of scattered alphabets, seasoned with random numbers. As if the admin tasks of some recording demon had been upsourced and visited upon the occupants here; converted into mundane chores they are expected, endlessly, ceaselessly, to perform, failing which they will be cast into even remoter darkness – damned if they do and damned if they don’t. The only reason for the absence of a sign requiring entrants to abandon all hope is that, as every office worker knows, it’s not the hope that kills you.

It’s knowing it’s the hope that kills you that kills you.

The Slough House series – Real Tigers follows Slow Horses and Dead Lions – is a pure, addictive delight to read, very much in spite of all the problems you can spot even in that brief excerpt. Herron’s prose abounds in cliches, tautologies, and whatever the hell that final line is, that kind of Hollywood-style tag-line that sounds cool but is actually gibberish. Whatever you call that, Herron has a pronounced weakness for it. At one point a character mutters the cliché “water under the bridge,” and then we get another of those weird mean-nothing lines: “But he said this with the air of one who spent a lot of time on bridges, waiting for the bodies of his enemies to float past.” I love it, but I don’t get it.

In this latest Slough House story, recovering alcoholic Catherine Standish, the assistant to Slough House’s brutish boss Jackson Lamb, has disappeared. In short order, the “slow horses” receive a ransom demand for her release: they must infiltrate Regent’s Park and steal vital, heavily-guarded information for the kidnapers if they want to see Standish alive again.

In many ways, it’s the plot we’ve been waiting two books to read: our battered, self-destructive losers must prove their worth by taking on M15’s best and, in their offbeat way, winning. “Nobody left Slough House at the end of the day feeling like they’d contributed to the security of the nation,” we’re told at one point, but this might one case in which that ends up not being true – and you can tell Herron relishes the strangeness of that every bit as much as he intends us to.