A decade after he introduced a crew of flawed secret agents caught between sinister plotters and cynical spymasters in the novel Slow Horses, Herron is a best-selling, award-winning writer who has been called the heir to master of espionage John le Carre.

A seventh novel in his spy series, Slough House, is out this week, and a TV adaptation is in production with an A-list cast led by Gary Oldman.

But initially, few took notice.

"Maybe it just wasn't the right time," the soft-spoken Herron recalled recently. "There were voices in my publishing company at the time that were saying the politics of the book were pretty ridiculous because it's all about the far right and references to (Britain) possibly leaving the European Union."

After a decade that saw Brexit roil Britain and populism surge around the globe, Herron's fictional world of damaged secret agents, self-serving politicians and buck-passing bureaucrats seems to capture 21st-century anxieties much as le Carre's morally ambiguous tales caught the spirit of the Cold War.

Herron's spies have all been banished from MI5 headquarters to do dull work in a drab London office building - Slough (rhymes with cow) House - for career-wrecking mistakes. This band of "slow horses" is presided over by Jackson Lamb, a flatulent, chain-smoking former field agent who alternates between lethargy, insults and flashes of ruthless brilliance.

Herron's spies bicker in the office kitchen and worry about money - a mundane existence periodically interrupted by traumatic events.

It was one such trauma that Herron says "made me want to write about larger events". He was working as a copy editor in London when suicide bombers killed 52 commuters on the city's transit system on July 7, 2005.

"I realised that to be involved, in however small a way, in something like that, all you had to do is be a citizen, a member of a city," 58-year-old Herron told The Associated Press from his home in the university city of Oxford. "We're all, I don't want to say combatants, but we're all potential victims.

"The idea of a terrorist event as an intrusion on ordinary life, on everyday life, that became something I wanted to write about."

At the time Herron was writing a detective series, but found spies better suited his desire for "state of the world" novels.

Violence, usually senseless, often erupts in Herron's books, but it's offset by a large dose of mordant wit. His cleverly plotted page-turners are driven by dialogue that bristles with one-liners.

Much of the humor comes from Herron's sharp eye for the way bureaucracies, whether corporate or clandestine, function and malfunction. The world of Slough House is closer to "The Office" than to 007.

"I have no experience of the covert world," Herron said. "But I have worked in offices. And I've worked for a company that ended up being part of a much bigger company. And what I've noticed is that the larger an organization gets, the more dysfunctional it becomes.

"I wanted to show a world where bad things happen because people make errors. And that's the basis of the series, because all the people in Slough House have made errors of one sort or another. But also it just seems to me it's how the world works."

Slough House was written before the coronavirus pandemic, but there are plenty of real-world echoes, including references to Brexit and the 2018 nerve-agent poisoning of a former Russian spy in the English city of Salisbury.

Then there is the rumpled, unscrupulous, bicycle-riding British politician Peter Judd, a character Herron insists "was never specifically intended to reflect" Prime Minister Boris Johnson.

"He was intended to reflect a particular kind of privileged, self-seeking, self-interested, ambitious, untrustworthy, unprincipled politician," said Herron, who attended Oxford University's Balliol College at the same time as the current prime minister. "I can see why people do relate that to Boris Johnson."

Herron's damaged but indomitable secret agents include River Cartwright, grandson of a legendary spymaster; dependable recovering alcoholic Catherine Standish; socially inept computer wizard Roderick Ho; and Shirley Dander, a dynamo fueled by rage and cocaine.

Herron says he is fond of them all, but he has no qualms about killing off long-standing characters. It helps to keep readers on edge. He's grateful for his loyal readers, though he is slightly alarmed by how much some embrace the misanthropic Lamb and his repertoire of luridly offensive put-downs.

By the time it is broadcast, the world may have returned to something like normality. Herron has been working on his next book during lockdown, but he doesn't think it will dwell too much on the experience of the pandemic.