"Bad Actors" is Mick Herron's eighth novel chronicling the exploits of the "slow horses," a motley unit of disgraced British secret-service agents condemned to live out their days in pointless, make-work tasks at Slough House.

The place is a near-derelict London office building, a fitting habitat for the group's boss, Jackson Lamb, a slovenly, flatulent, foul-mouthed tyrant. Among his underlings are a recovering alcoholic, a former sex addict, an unrepentant drug fiend with a craving for violence, the hapless son of a legendary Cold War spy, a crass, would-be lothario and action hero, and a few other losers and lost souls. (The series has spawned an excellent TV series from Apple-TV starring Gary Oldman, Olivia Cooke, Kristin Scott Thomas, Jonathan Pryce and Jack Lowden.)

Although grinding office drudgery is meant to be their lot, the slow horses invariably get sucked into lethal intelligence-agency and political conspiracies. And, one way or another, these byzantine affairs involve the ruthless schemer and backstabber, Diana Taverner, now "first desk" at Herron's version of MI5, the place "where plots were hatched and nurtured and set loose from their cages."

"Bad Actors" treats us to a nasty piece of work called Sparrow, enforcer and special adviser to the prime minister. Sparrow has been using his loosely defined position to arrogate power to himself and, thanks to the prime minister's ineptitude and inattention, he is succeeding.

Though not named, the man in Number 10 is clearly Boris Johnson, ambitious but "dumbstruck by the demands of office: the pay-cut, the long hours, the pandemic, and the shocking degree of accountability involved. For a man who'd made a vocation out of avoidance of responsibility, this last was an ugly blow."

Proceeding apace, Sparrow has set in motion a plot to remove Taverner from the picture and place MI5 under his control. Even to begin to summarize the scheme's twisted nature would be to give too much away — but, yes, Russians are involved.

Herron's plots are masterpieces of convolution and elegant wrong-footing. Beyond that, his action scenes are fast-paced and thrilling — there are a couple of high-octane doozies in this installment. But the real draw of the series is its dark, dark humor. Much of it is interpersonal, but the most biting of all concerns the state of Britain, a country beset by Brexit, COVID and incompetent, if mercenary, leadership.

Meanwhile, dominating all is London, reverberating with "the tumbling wet slap of money being laundered, over and over again."

If there is bad news, it is that you really should have read some of the previous Slough House novels in order to get a handle on this party of rejects, their histories and capabilities. Further, if you are a veteran of the series, you may have become a little weary of Jackson Lamb's extravagant foulness and his habit of magicking cigarettes and even himself out of nowhere. That said, this is still one of the most enjoyable series I have ever read.

Katherine A. Powers, a Minnesota native, also reviews for the Washington Post and the Wall Street Journal.

Bad Actors

By: Mick Herron.

Publisher: Soho, 360 pages, $27.95.