Mick Herron fans will rejoice at the return of the Slow Horses in this, the ninth in the sequence of acclaimed novels tracking the adventures of spies who haven’t so much come in from the cold but are still shivering, unwelcome, outside the door.

While Herron has played down comparisons with the spymaster extraordinaire John Le Carré in interviews publicising Clown Town, there’s a strong case to be made for the resonances.

Both writers stress the unglamorous side of the spying business, and even if Herron’s lighter tone gives the initial impression of betrayals being played for laughs there’s still a grim reality when the tradecraft turns violent. 

In Clown Town, for instance, protagonist River Cartwright is still recovering from his encounter with a poisonous nerve agent in the previous book, a mishap that left him in a coma.

Plot features a contemporary resonance

One of Herron’s characteristic ploys is to give his plots a contemporary resonance: the nerve agent which incapacitates River is novichok — recalling the poison which was administered in a botched assassination attempt on Sergei and Yulia Skripal in Salisbury in 2018.

Readers will definitely recognise the inspiration behind the charismatic if unprincipled politician Peter Judd, an unreliable minister with a rackety private life and shadowy past who plays a central role in this book.

There are also plenty of real-life parallels to occupy Irish readers. Take this extract from early in the book: “Pitchfork was the operation, and also the codename of its subject. Dougal — Dougie — Malone, long-time IRA enforcer, and the owner of a well-earned reputation for brutality, fostered not simply by his keenness for punishment beatings, but by the methods he chose to implement them: the hammer, the car jack, the crowbar …

“For two decades he was the Provos’ iron fist in its studded glove …

“And for half the time he enjoyed such power he had been an informer for the British intelligence service, an asset so highly valued that he had a team of four assigned to his care and security.”

This is the main engine of the plot: the operatives who ran Pitchfork on behalf of British security services are now disaffected and looking for their due, which means trouble for Diana Taverner, head of M15 — First Desk, in the parlance — and trouble for her means trouble for Jackson Lamb, reluctant wrangler of the Slow Horses.

The timing of this release is apposite, though hardly accidental. The Slow Horses series of books has attracted a whole new cohort of fans due to the much-praised Apple TV adaptation, with the eagerly awaited new series out this month. 

Jack Lowden, whose name has been mentioned as a possible James Bond, brings an appealing weariness to the central role of River Cartwright, and Kristin Scott Thomas is a class act as Diana Taverner, but Gary Oldman’s Jackson Lamb is a character for the ages, flatulent, sweary, but with a brain as sharp as his magnificently insulting one-liners. 

(The only negative is the desperation of other studios and streamers to emulate its success has led to a rash of weak wannabes such as Department Q on Netflix).

Does Clown Town deserve its place in the Slough House pantheon? There are quibbles: that missing volume in River’s grandfather’s library seems a stretch as an inciting incident, while the traditional opening gambit — describing the building occupied by the Slow Horses from top to bottom — wore out its welcome a few books ago.

But those are quibbles. This is still a must-read series, and it will be as long as Jackson Lamb is belching his way upstairs to his office in Slough House.