There is some distance between the Cannery Row of John Steinbeck’s 1945 novel and Slough House, the London headquarters of Mick Herron’s floundering intelligence officers. But that literary journey has brought Herron soaring sales and growing critical acclaim as one of Britain’s best-regarded spy novelists. The seventh instalment of his Slow Horses series — a novel titled Slough House — is now out, and an adaptation for Apple TV is in the making.

Even so, Herron remains alert to his early influences. “Steinbeck, and his books like Cannery Row, had a big effect on the way I write,” he says. “He wrote great dialogue. The way he handled a large cast of characters and had them interact with each other has always struck me as one of the finest examples of how to do this.”

Like the previous volumes, Slough House has been praised for its distinctive take on the espionage genre; the series is populated by an ensemble cast of has-beens — the “Slow Horses” — that instead of being fired by MI5, are put out to pasture.

First among losers is Jackson Lamb, a shambling, obese and frequently flatulent misanthrope who appears in each of the books. Though neither a James Bond-style action hero, nor a cerebral George Smiley type, Lamb — like many of the Slow Horses — is decent, courageous and intensely loyal. He can accelerate from a canter to a gallop when necessary.

“Lamb casts the biggest shadow because of the things he says, but he is not a spy hero in the usual mould,” says Herron. “He has turned his back on that. He is full of self-loathing for the way he has lived and things he has done. That is the key driver of his character — but what triggers him is when his Slow Horses are in danger.”

Slough House draws on real-life events — the gilets jaunes protests in France, the tsunami of dirty money sloshing through London, a poisoning by the Russian secret service. It also features an ambitious politician — described in a previous volume as “a loose cannon with a floppy haircut and a bicycle” — called Peter Judd, or PJ. Sound familiar? Herron studied English at Oxford at the same time as Boris Johnson, but they moved in very different circles. Meanwhile the Slow Horses themselves are under attack, victims of kidnap and killing as their records are removed from the intelligence services’ database.

Herron’s distinctive voice, marked by a dry wit and mordant sense of humour, runs through the series, and his latest work is no exception. Here is Louise Guy, another of the Slow Horses, her attention distracted on a London Underground train while commuting to Slough House: “Looking for donor sperm? read the ad above her head. Definitely not, although on the Central line at rush hour, you could not rule it out. But for the moment [she] hoped herself impregnable.”

On one level, the Slow Horses series seems a very British creation, in the tradition of classic 1970s TV programmes such as Rising Damp and Porridge. But beyond the gallons of tea, worn office furniture, and dark comedy is a deeper story with universal resonance — one of resilience, of people deemed to be failures who refuse to accept such a fate. “The whole point of Slough House is to demoralise [these agents] and make them leave the service,” says Herron. “But they stay because they are committed to the ambitions they had when they were younger.”

In the Apple TV series, currently in production, Gary Oldman (known for his interpretation of George Smiley in the 2011 film Tinker Tailor Soldier Spy) stars as Lamb. Oldman is joined by Kristin Scott Thomas in the role of Diana Taverner, a high-ranking MI5 officer, and Jack Lowden, who plays River Cartwright, one of the sharpest of the Slow Horses. Herron has spent time in the writers’ room, and also visited the set, but otherwise is not creatively involved. “The TV version is taking place at one remove. I work best on the page, that’s where my energies go.”

Unlike many of his predecessors and contemporaries, Herron has never worked for the intelligence services; until 2017 he worked as a sub-editor, writing 350 words each evening after work. His stories, he says, do not need to be authentic, but must be plausible. “Spy novels and films are part of our culture. Anyone can make it up if they have that kind of background. Like most writers I know, I am magpie-like.”

As for future plans, Herron is working on the eighth volume of the series, and also a collection of short stories, with tales featuring Jackson Lamb, which will be published later in the year. “I will not shut the door on Slough House. I find it a very useful vehicle for writing about contemporary issues,” he says. “And I have not killed all the characters yet.”

Adam LeBor is the author of ‘Kossuth Square’, a Budapest noir crime thriller

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