In the event, they chose the name Sam after Freedland's second son (the first had already had a work of non-fiction - Jacob's Gift - named after him) and Geller added the Bourne part when he saw a poster for the summer film blockbuster, The Bourne Identity. The novel, set in the Chasidic community of Crown Heights in New York, was not classic material for a number-one bestseller. "It's an extremely Jewish book. There are discussions on notions like pikuach nefesh and I quote from the Yom Kippur liturgy," says Freedland.
The book, however, sold more than 600,000 copies, largely due, Freedland freely acknowledges, to "the twin gods of Richard and Judy". Richard and Judy's book club on their Channel 4 show can make a book into an instant bestseller. The effect on The Righteous Men was as almost dramatic as the action in the book. Freedland recalls watching Richard and Judy announce that the novel had been chosen.
"Judy announced that the following week they would be discussing The Righteous Men. She described it as a sort of Jewish Da Vinci Code. Off camera, Richard added that he thought it was better than the Da Vinci Code. One hour later, the book was either number one or number two on the Amazon bestseller list - it had been nowhere before."
A week later it topped the bestsellers list and stayed there longer than any other book in 2006 - not bad for a project that Freedland had seen as a sideline to his main career as a political journalist. Immediately, Freedland was under "intense pressure" from publisher HarperCollins to produce a follow-up. The Last Testament was set amid the tension and violence of Israel and the Middle East. It sold another 350,000 copies.
Now, Freedland, or should that be Bourne, is publishing his third novel. The Final Reckoning is also on a Jewish theme. Freedland says he feels no particular compulsion to write Jewish novels, but it is no coincidence that with his own background he should favour these themes.
"There is a sense that you write what you know. I had an initial discussion with publishers. They asked me what I planned to do next, so I told them about this true story I had in mind. They were gripped by it - transfixed, actually. I had only got a quarter of the way through telling them about it when they said ‘you've got to do this'."
The story Freedland was telling makes up the core of The Final Reckoning. It is the real- life story of how a handful of Holocaust survivors called The Avengers sought to settle scores with those who had perpetrated the slaughter of six million Jews across Europe.
"It's such a dramatic story. It's almost biblical in its thirst for justice and revenge against the greatest crime in human history. However, I was very aware of exploiting or being seen to exploit the Holocaust. So, apart from the elements which are obviously fictional, I have gone to great lengths to ensure that anything about the Holocaust in the book is true."
Crucially, he decided that, while it was legitimate for a work of popular fiction to address some of the murkier details of the Second World War, there was one place he did not want to go. "I made an unwavering decision not to go near the death camps. It is unimaginable in this kind of book. I leave that to the likes of Elie Wiesel and Primo Levi."
The massive, unexpected success of Bourne has been immensely rewarding for Freedland, but has also given him problems, most obviously that of how to find time to fulfil his commitments.
"I'm still a staff columnist at The Guardian but I'm very lucky to have an understanding employer. I have reduced my workload as much as I can but it is pretty intensive, there are quite a few weekends and a few nights when I have been up till three in the morning."
However, he still does not feel secure enough to give up the day job, nor, on reflection, does he want to. He sees the two forms of writing as symbiotic. As a journalist he was always frustrated that he could not always tell the whole story.
"You can only ever convey three-quarters of the texture of a meeting. What is really going on is what you tell your wife and friends when you go home. Somehow, writing about the basic humanity of your interview subject can look inappropriate, so you just don't include it. In fiction, it is these details you are looking for - the hesitations, the body language."
His fiction writing draws on his journalism. The day after our interview, he was due to fly to Berlin to report Barack Obama's speech to a huge audience in the German capital. "I can't deny that five per cent of me is thinking this would make a great scene in a political thriller. If I didn't work as a journalist, I would get some of my life back, but it's a privilege to have a platform in papers that a great many people read."
Freedland has wanted to be a writer ever since he was old enough not to want to be a train-driver any more. Part of the inspiration came from his family. Both parents were journalists and one of Freedland's early memories is of being asked to help out with recording equipment when his father, Michael Freedland, was making his popular radio programme, You Don't Have to Be Jewish.
He also takes from his family his great love for Israel. "I was surrounded by Jewish conversation. My mother came from a very religious backgrounds and my father was steeped in the politics of the community. It made me very positive about being Jewish. My own family experiences are interwoven with Israel's experiences."
So does his affection for Israel create problems for him at The Guardian - not known as the Jewish state's greatest fan? "I can't deny that there is a body of Guardian readers who have a great deal of hostility to Israel. But unless you want to preach to the converted, that has to be fine. I welcome that engagement. Besides, how can I complain if there are readers who are worried by Israel's presence in the territories gained in 1967? Yes, they have a problem with that - but so do I."
However, Freedland does not agree that The Guardian has an anti-Israel stance. "When people complain about articles in The Guardian, they are almost always talking about outside submissions rather than pieces written by staff journalists. That is the price you pay for being involved with a paper that believes in publishing the widest possible range of voices."
He adds: "The Guardian believes not only in Israel's right to exist but goes further. In a 2001 editorial, it stated that the creation of the state of Israel was ‘a moral necessity'. That is the Guardian view of Israel."
When Freedland is not wrestling with the Middle East peace process, he spends time wrestling with whether it is possible to set The Righteous Men somewhere other than the Chasidic community. He says he has had "a nibble of interest" from Hollywood but the studios are wary of a Charedi setting following the flop of Melanie Griffith's kosher turkey, A Stranger Among Us.
If anyone can do it, Freedland can - with a little help from his friend Sam, that is.
The Final Reckoning is published by Harper Collins at £6.99
When Freedland wrote what turned out to be his first blockbusting novel three years ago, his agent (and childhood friend) Jonny Geller suggested that he adopt a nom de plume. Freedland says: "The name was Jonny's idea. He is a genius of the publishing business, and when he originally pitched my first thriller, The Righteous Men, he said we should not pitch it under my name. I think he thought they might be put off by my job, which he described as ‘a pointy-headed columnist for a pointy-headed publication'."