James Comey knows the exact moment his life changed forever. It was a Friday night, October 28, 1977, and the future head of the FBI was home alone with his 15-year-old brother.

Comey, aged 16 and a self-confessed “nerd”, was working on a piece for his school’s literary magazine while Pete watched TV in the basement when a gunman kicked open the door to their modest house in Allendale, New Jersey.

Between March and October, four young women in a neighbouring borough had been assaulted by a predator dubbed the “Ramsey Rapist”. Now a middle-aged man matching his description was holding Comey and his brother at gunpoint.

“Time slowed down in a way I have never again experienced,” he later recalled. “I lost my sight for an instant. It returned in a strange haze and my entire body pulsed, as if my heart had grown too big for my chest.”

Locked in the basement as the man ransacked their home for valuables, the boys scrambled through a small window, only to encounter the intruder again in the garden.

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Comey, whose subsequent career pitted him against the Mob and Donald Trump, was convinced they were going to die until a neighbour’s dog caused their captor to flee. Remarkably, he returned to school the following week where sharing his story, he now believes, helped stave off trauma.

“Every one of my teachers had me go to the front of the room and tell the story to the class,” he says. “I couldn’t see it then, but I was processing the trauma over and over again, reducing its power over me.”

Even so, he thought about the intruder every night for five years and slept with a knife in easy reach for far longer.

“The police thought he had done surveillance on our home, seen my sister Trish and thought the figure lying on the floor watching TV in the basement was her,” he says.

“Thank god it was my brother or that night would have been even more horrific.”

Although a suspect was eventually caught, he was never convicted. “No one was held accountable, but the attacks stopped the night he came into my house,” he adds.

Today, the terrifying experience, which he likes to believe made him a better person, is one of several formative incidents in a life that reads like a thriller. “I didn’t worry about a lot of things that bothered my peers after that. It’s hard to describe. I knew I was going to get killed, and that was life-altering in a good way. It made me a better investigator dealing with victims of crime.”

Remarkably, Comey – who also suffered badly from bullies, admitting: “I can still remember trying to choose a different path every day to school to avoid them” – still thought his future lay in medicine.

Born in the modest New York suburb of Yonkers where his father worked for an oil firm, scouting new sites for petrol stations, he majored in chemistry and religious studies at university in Virginia, before going to law school in Chicago.

It seems likely now this early adherence to science-based evidence, combined with a strong ethical and moral compass, helped prepare him for later life.

But even as a young law graduate, Comey’s future was not decided until, working as a clerk to a New York judge, he watched mesmerised at a bail hearing for a pair of notorious mobsters – Anthony “Fat Tony” Salerno and Vincent “Fish” Cafaro.

“These two young prosecutors were not much older than me, but they stood up straight, answered directly and never over-reached,” he says. “At that moment, I decided I was going to be in law enforcement. I told my girlfriend, now my wife, ‘These are the biggest bullies there are’ – it was that which drove me.”

The then inspirational, now infamous, Rudy Giuliani was cutting a swathe through organised crime as a US Attorney in New York at the time and Comey signed up. It was the beginning of a stellar career in law enforcement.

In 1992, while working as US attorney in New York, he jailed notorious Gambino Family boss John Gotti (who, he notes, had his hair cut every day) for extortion, robbery and murder.

By 2012, Comey had been appointed by Barack Obama, with bi-partisan support, to a 10-year term as the seventh director of the FBI. On learning four out of five of his agents were white, he saw that his mission was to make the organisation more reflective of modern America.

“My worry was that the organisation was growing steadily more male and white. [Former director] Bob Mueller was a very good guy, a person of tremendous integrity –but I just don’t think it was a focus of his. But I worried that could become a fall down a flight of stairs. If you’re going to be effective about protecting America, you can’t all look like me.”

Fired four years into his term in May 2017 by Donald Trump, for refusing to turn a blind eye to alleged collusion between his presidential campaign and Russian officials, he has embarked on a career as a crime writer.

“It’s lonelier, obviously, which fits my personality better. I heard someone describe me as a socially adept introvert,” he smiles.“But writing is less challenging and a lot less complicated than running the FBI. And I can wear anything I want.”

While his blue “G-man” suits might be in his closet, the ramrod-straight back, sense of mission and imposing physical figure – he is 6ft 8ins and in sterling shape for a 62-year-old – remain unmistakable. His snappy courtroom thriller, Central Park West, draws dramatically and accurately on his long career, reflecting his run-ins with the Mafia.

It includes the assassination of a #MeToo-accused former New York governor, art thieves and an abundance of compellingly shady characters.

It is the first in a series featuring the inner-workings of the FBI and CIA.“I wanted to take people inside these cases and high-stakes investigations in a way that is real but also gripping,” he explains. “I’ve heard people generate excitement in crime fiction by having the actors go rogue. My pitch was, it’s exciting even if you’re doing it the way you’re supposed to.”

Meeting in London, Comey explains how his dogged New York prosecutor Nora Carlton is based on his oldest daughter, Maurene. The 34-year-old, was lead prosecutor against Ghislaine Maxwell in the courtroom where Comey once took on the Mob.

She would also have prosecuted billionaire paedophile Jeffrey Epstein had he not taken his own life in prison. “When she was four years old, I was in that very courtroom – number 318 – and it looks exactly the same,” he says. “It was suddenly obvious my protagonist should be inspired by her.”

Other characters populated from Comey’s real-life experiences include Nora’s Justice Department colleague Benny Duggan, based on famed anti-Mafia investigator Kenny McCabe who always treated his targets with a modicum of respect.

“Once, he was on surveillance and a younger mobster saw his car and spit on it. Kenny started to get out, lord knows what he would’ve done, but the mob boss he was conducting surveillance on, grabbed the guy, slammed him against the car and said, ‘Don’t you ever disrespect Kenny’.

“He was unknown publicly, but such a legend among both bad and good guys, that the New York Times did an obituary when he died in 2006.”

As for baddies, Comey has no shortage of real-life mobsters to draw upon. Just don’t expect his fictional mobsters to be anything like their counterparts in The Sopranos or The Godfather. “I used to tell my children evil has an ordinary face,” he adds.

Comey remains best-known for two investigations: Hilary Clinton’s use of a private email server while secretary of state (she was cleared twice, but believes the second inquiry, revealed days before the 2016 election, damaged her chances); and the subsequent inquiry into alleged Russian interference in the Trump victory.

Today the ex-FBI boss admits he managed to upset both sides of the political divide – the left, with Clinton, then the right, with Trump. He blames his ultimate downfall, in part, on the fact the FBI had remained scrupulously impartial, and thus had no political favours to call in when the chips were down.

“Obama was explicit when he invited me to the Oval Office, just to get to know one another. He said, ‘This will be the last time you and I speak like this’. He kept his word.” By contrast, Trump invited Comey to a private dinner for two at the White House a week after his inauguration and tried to seduce the FBI boss into swearing personal fealty.

“President Trump reminded me of a Costa Nostra leader – there was the sense that ‘not only are we going to be close, but you’re on my team, you’ll pledge loyalty to me, not to my office or the structure under our constitution, but to me personally’. That’s a really dangerous thing to contemplate when you think about the power of the FBI.”

Ultimately, that fierce independence in the face of Trump’s calls for Mafia-style loyalty cost him his job, something he still grieves over.

“I think I ended up as director of the FBI during a uniquely polarising time for America. My wife’s question was, ‘I get it, but why does it have to be you?’ My answer was, ‘Because who else would do it?’ And I can’t go through life trying to avoid hard decisions.”

Comey, who lives in Virginia with Patrice, a therapist, has five children and three grandchildren. The couple lost another son, Colin, to sepsis within a few days of his birth, another tragedy that had formed him.

“I guess you can’t ever know anyone else’s pain, but my sense was my wife’s was even deeper than my own, because she’d carried him for nine months. My instinct was to shield our children from the pain of their brother dying and hers was the opposite, otherwise it will loom so large in their lives. She was so right and I was so wrong.”

Today, despite everything, he says he is still optimistic about America. “The rule of law held which is the often untold and really good part of the story. Think about the lies that came after the 2020 election.

“You can say whatever you want with hair dye running down your face outside some landscaping shop [as Giuliani did] but when you go into an American courtroom you’d better speak the truth. If you think of the record of those lies [about who won], I think it’s 60 court decisions all saying ‘no’.

“Those judges were from both political parties; city level, county level, federal level… but they’re all rooted in the culture of the US legal system and it held.”

So how does he explain Donald Trump, who he describes as a demagogue? “I’ve never met an adult with a greater hunger for affirmation and that hunger just dominates his life,” he says.

“That’s the trap of deep personal insecurity, nothing externally can fill the hole, because the hole is in the centre of your identity. It’s a bottomless hole. It doesn’t matter what role you occupy, you still feel the imposter. That dominates him and I’m sure it will for his entire life.

“I think about how much joy I take from being with my children and grandchildren. A wonderful day for me is when I can just draw with chalk with my grandchildren. I can’t imagine Donald Trump ever having a day like that, because that’s a day without affirmation, it’s a day when you’re caring for someone else.”

Put like that, one almost feels sympathy for the 45th president. But he adds quickly: “For our country, it’s about managing the threat he represents. You should feel a sense of empathy for a person in that much pain. But then we’ve got to move past that to figure out how we’re gonna protect the republic from what he represents.”

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