Naturally, I'm listening attentively to every word Ken Follett is saying about his new book, Fall of Giants. But it's impossible not to surreptitiously check for obvious signs of his immense wealth at the same time. This, after all, is an author who has sold more than 100 million copies of his books, who has three homes and a staff of 16 "for keeping track of the money".
He was the only British writer in the recent Forbes list of the world's highest paid authors (fifth at £13m, or Dh76m). He even donated £100,000 to a campaign for a candidate in the recent Labour leadership election whom he must have known would not win. And sure enough, Ed Balls didn't.
But there's no expensive suit; Follett's watch does not suggest a man of status; and his unruly silver hair looks like it needs a cut. It would be ridiculous - not to say slightly worrying - to expect him to strut into the room laden with bling. This, after all, is a 61-year-old man married to Barbara Follett, a noted feminist. But it takes just one glimpse of her husband's shirt, as he leans forward in his chair, to confirm that he still enjoys the trappings of money that earned the couple the tag "champagne socialists" in the late 1990s. For this shirt is discreetly imprinted with the letters KF.
Monogramming your clothing is probably the kind of thing you feel entitled to do if you sell 100 million books. Follett shot to worldwide fame with the 1978 spy thriller Eye of the Needle, but he's widely known for The Pillars of the Earth a decade later, and its 2008 sequel World Without End. Translated around the world, The Pillars of the Earth in particular encouraged the cult of Follett. In Spain, there is a statue of him - not wearing a monogrammed shirt, as far as we can tell. Ridley Scott is the executive producer of a new Pillars mini-series. And yet, such popularity is ostensibly based on a historical epic, which tracks the 23 years it takes to build a cathedral in the 12th century. At 976 pages, it can often feel like all of those 23 years have been chronicled in minute detail, and such length - combined with an unashamed page-turning style - means Follett has often been derided by literary critics.
Still, he's not shy in returning their fire. "There's no way that the Booker is a prize for general excellence," he says, remarkably genially. "Of course, I realise full well that people have many other definitions, but for me it's doing everything to make a reader react to a story emotionally, as if it was real. That's excellence."
Making next year's longlist is unlikely, then, but Fall Of Giants will almost certainly outsell the combined efforts of the literary set next year. Does this create a pressure? Actually, success appears to have emboldened Follett. The very first thing he says to me, a glint in his eye as he surveys a room stacked with signed copies, is revealing. "I hoped the reaction to World Without End would be good, of course, but it was overwhelming. And I wanted the same again! It sort of spoiled me."
It's also meant that Follett has now reached that stage afforded to very few authors - people will buy his books no matter how sniffy the reviews might be (and they often are). So why do people buy them? Because Follett's only motivation is to write stories that will enchant millions of people. He might have to employ a system of business-like spreadsheets to keep up with his characters, but it's all in the name of storytelling.
"The greatest asset I have as a writer is all those people who are looking forward to the next book," he admits. "So the very worst thing I could possibly do professionally would be to disappoint them. That's very much on my mind, and it makes me rewrite things when otherwise I might not. You write a page and think: 'Ok, that's not the best page ever, but it'll do.' And then you think: 'hang on, five to 10 million people are probably going to read this! Tear it up and write it again...'"
Fall of Giants is impeccably researched and constructed: "A logical story with no boring bits," as Follett puts it, smiling. The first part of a trilogy that spans the 20th century, it has the elements that all Follett fans love - the extensive list of characters at the start, the sweeping family story spanning decades and the back-breaking 864 pages. It's also clever. If a mediaeval epic appealed to so many millions, a story that has more recent relevance could potentially be even more successful.
"The 20th century is not only the most violent and dramatic 100 years in human history, I think, but the story of all of us," Follett says. "I've lived through half of it, all of my readers would have lived through some of it and their parents, grandparents and so on lived through the rest of it. So it's about where we all come from, in a way. "Naturally, I hope that when people finally put the book down they will think it was great. But I also hope people will get why we had World War I, why the Bolsheviks won the Russian Revolution, why the feminists won the battle for the vote. I hope they'll feel that part of their own past is now much clearer to them."
But there is a fine line between historical fiction and a novel that simply tips over into a textbook. Follett's desire to be authentic means that the words spoken by Churchill to his made-up Edwardian aristocrat Fitz were indeed uttered - just not to a fictional character. Follett was very keen to get the details of the Battle of the Somme absolutely correct. Nevertheless, the five families in Fall of Giants - taking in everyone from the coalminer to the aristocrat - have interlocking stories, feeding the drama that is so key to this book's page-turning quality.
"To be a popular novel, it has to be a story about individuals - their destinies and their relationships," he admits. "The characters have to be passionately involved with whatever the historical events are - the Somme, the storming of the Winter Palace and so on. The demands of my public are such that they want to feel anxious about how a scene will turn out, and they can only do that if they believe in the characters as people."
It's interesting that Follett should call his readership "my public". It sounds like the words of the patrician he most certainly is not. But, as he was there at the birth and death of New Labour (his wife was named in last year's expenses scandal and stood down), I wonder whether he felt the need to educate his readers. After all, Fall of Giants is unquestionably his most political book to date. "I'm not consciously advancing my own political views - but what my unconscious does, of course, is a whole different matter. You can't help that, and there's no secret as to where my sympathies lie. Many of the admirable people in Fall of Giants adhere to what I think is the most hopeful political line, which is ultimately the middle of the road. Given that the Edwardian Conservatives were doomed in their hope of keeping the old way of life going, and the Bolsheviks' workers' paradise was a pipedream, the people who have some sense of the future are in the middle - the Liberals and the fledgling Labour party."
So it will be interesting, then, to see how Follett approaches the third book in this trilogy - the period in which he was most involved in politics himself. In a way, he's given himself a get-out clause - the story will end with the fall of the Berlin Wall rather than the rise of New Labour. The man who funded and helped mastermind much of Tony Blair's party has no inclination to read his new memoir, either. "Why? How can I put this: I suspect that it may not be entirely true."
Still, this trilogy is certainly the most personal book Follett has written. It's set in Wales where he comes from and is full of his politics and interests. And, just maybe, it does have a higher ambition than mere storytelling this time around. "Why do we read literature?" he concludes with a flourish. "To broaden our minds as well as for pleasure and the sense of adventure. So in Fall of Giants there are Russian factory workers, Edwardian aristocrats, coalminers, young American politicians. The lives of people whose circumstances and life stories are completely different from our own. But it's through literature that we get this very broad picture of life on earth. If we didn't have literature, we'd hardly know anything."
Fall Of Giants (PanMacmillan) is out now.