A solitary figure in a navy linen suit stands alone on the platform of a deserted rural train station. Robert Harris’s brief missives have contained no mobile number or address, simply instructions to catch the 11.17 from Paddington. He will meet me off the train in person, he says – it’s safer that way.

Or at least that's what he would have said if this were a Robert Harris novel. But there is still a certain amount of suspense as we wander down the canal in Kintbury, the quaint Berkshire village where Harris lives. Any moment now we’re going to light upon the gigantic, Gothic-revival house that he bought with the proceeds of his staggeringly successful novel Fatherland.

Because the book, which launched Harris’s career as a bestselling novelist, imagined a parallel world where Germany had won the Second World War, his opulent country pile became known among his friends as “the house that Hitler bought”.   

“I’ve taken down the Nazi banner just for you,” he jokes as we walk up the gravel drive. Once inside, our progress followed by TS Eliot and Byron, whose portraits stare down from the wall, we make our way across polished wooden floors and Persian rugs towards the living room.

“Would you like a drink-drink or a just coffee?” Harris asks before we begin the interview. He pours himself a pre-prandial glass of pink fizz. It’s a fitting drink for a novelist in the less frenetic stage of his writing cycle, in which intensive, six-month bursts of composition are followed by more relaxed periods of research for the next book, and promotion of the last. Harris is currently gearing up to write the third in his Cicero trilogy (his tenth novel), and is also publicising An Officer and a Spy – a thriller based on the Dreyfus affair, which has just come out in paperback.

As a former political journalist, he thrives on deadlines, which explains his rigorous routine. On writing days, work starts at 5.30am. Even as his books are being written, his publishers are busy designing their cover jackets and selling them to the bookshops. It’s the kind of pressure that would give some novelists an aneurism. Doesn’t he find it stressful?

“No,” says Harris, whose manner in person is unhurried and understated. “But it is difficult. Anything you're going to do well you're going to find difficult. You wouldn’t expect a runner in a race to stroll off the field without breaking a sweat, and it's the same with writing. You have to dig in and get it out.”

Harris also believes that “things are better taken at a gallop”, and that “the first version is the best”. He says he feels an affinity with Victorian novelists like Dickens and Thackeray who were working to tight deadlines. Like them, he doesn’t have much time to go back and revise his work.

Stress did once play a part in Harris’s working life. As a columnist for the Sunday Times in the early ’90s, his instructions from the paper’s then-editor Andrew Neil were to “annoy as many readers as he could” as a left-wing polemicist. Harris did with this gusto for a long time, but soon his weekly offering grew in length and prominence until it was the main column in the paper.

“I hated Thursdays when I had to think about what I was going to write,” he recalls. “I always had a knot of anxiety which would only be released by the exquisite pleasure of finishing on Friday lunch-time and going out for a drink. But that was the most stressful thing I've done.”

Robert Dennis Harris spent his early childhood on a Nottingham council estate. His father worked in a printing plant, partly inspiring Harris’s writing career. At Cambridge, he studied English and edited Varsity, the student newspaper. By the age of 30 he had become political editor of The Observer. He says he sometimes misses that feeling of “being in the swim”, but doesn’t regret swapping news for novels.

Politics might have provided an alternative career path. He developed an interest in Westminster at “a disgustingly precocious age”, writing, at the age of six, an essay entitled ‘Why me and my dad don't like Sir Alec Douglas-Home’. But he lacked that sense of political vocation, and was never really tempted to run for office. “I can understand politics like a sports writer can understand a football match without being able to play on the field themselves,” he says.

That hasn’t stopped Harris from forming some close friendships with politicians. He was for a time close to Blair (of whom more later) and Peter Mandelson remains one of his best friends. Perhaps surprisingly, given his journalistic association with New Labour, he is also pals with Andrew Mitchell, whom he met at Cambridge, and with George Osborne.

After Harris had settled on novel-writing, he also struck up a very close friendship with that titan of twentieth century liberalism: Roy Jenkins. In 1995, Jenkins had written a favourable newspaper review of Harris’ second novel Enigma and was invited by its publishers to the launch party.

“I had an enigma machine someone had lent me and I told Roy, who’d been at Bletchley Park, that he must come and see it,” Harris recalls. “Roy immediately whipped out this little diary and said, ‘Well, Jennifer and I could come to lunch on Sunday’. I thought, ‘Right, OK!’ So he came, it went well, and at the end he said, ‘This has been most agreeable, let us have lunch in a pub, I'll pay’. And then that was it, we went on lunching from ‘95 until he died in 2003. I was enormously fond of him.”

A new biography of Jenkins has just been written by John Campbell, but did Roy ever ask Harris to write one? The idea was mooted, apparently, but dismissed after Harris told Jenkins that he was supposed to be doing a life of John le Carré, but was “finding all le Carré’s women very embarrassing”. “Roy and Jennifer exchanged glances, and that was the way it was turned down,” Harris says.

Footsteps are heard coming down the vast wooden staircase and a flurry of activity begins in the kitchen. It is lunch-time in the Harris household and visiting journalists are invited. We join Harris’s wife Gill Hornby, a former Telegraph columnist and the sister of the novelist Nick Hornby, and one of their four children, Matilda, who is in the middle of a day of AS Level revision. Gill has been upstairs working on her second novel. Her first, The Hive, was a bestseller when it came out last year, but she’s suffering from writer’s block today, and cheerfully bemoans the requirement that novels must have plots. 

Has Matilda read any of her parents’ books?

“Um, I've read my mum's!” comes the reply – although the teenager is quick to add that she, y’know, very much likes her dad as a person. “He's a good father,” she says laughing.

Between mouthfuls of quiche and carrot salad, Harris and Hornby share the story of how they met. They were both at Newsnight, he as a reporter and she as a producer, and Harris asked the editor of the day (who happened to be Jim Naughtie’s wife) if the two of them could be sent on an assignment together. The pair were dispatched to interview the Labour MP Brian Sedgemore, and, in the taxi on the way back from Westminster, Hornby suddenly realised that they were going to get married. She laughs as she recalls how her feelings in that moment were not of optimism or joy, but rather resignation to the inevitable. They have been married for over 25 years now.

Back in the living room, conversation turns to Harris’s 2007 novel The Ghost – a roman à clef about a ghostwriter working on the memoirs of a charismatic ex-prime minister who has cosied up to the Americans and is facing trial for war crimes. (One newspaper review dubbed it ‘The Blair Snitch Project’.) Among many parallels with Tony Blair, to whom Harris was once very close, the fictional prime minister is often referred to in terms of his inscrutability. Is that how Harris saw Blair?

“I think that was later,” he says. “I think when one knew him first off one of the charms of him was that he seemed, as he said, 'a regular sort of guy'. I met him first in 1992, I think, and he seemed very much like the sort of man who would live next door to you – a fellow professional, commonsensical, friendly, approachable.

“Well, little did we know,” Harris says with a rueful laugh. “It’s impossible to see the man he is now in the man that I knew. Who knew that he would become a great friend of George Bush and would want to keep bombing people and would become so passionately interested in making money? I mean maybe someone more perceptive than I would have seen it, but I never saw that at the time, nor – knowing a lot of the people who know him very well – did they.

It’s a cliché to say that most politicians go mad if they're in office for more than about six or seven years, and they become a member of a club and you become quite disconnected from reality, and I think there were in Tony things we perhaps didn’t realise at the time – of narcissism, a messiah complex, that had merely accelerated this impulse in him.

Many people these days see Blair as a lost soul, not least after his recent suggestion that Britain should join forces with Putin to combat jihadism. Harris would go further.

“I find it tragic. It’s presumptuous of me to say so, but I can’t believe there isn’t an element of tragedy that he himself feels, that a relatively young man in political terms should cut himself off from British democracy in the way that he has. He could have had one of those nineteenth-century careers, and come back as foreign secretary or even as party leader, but he turned his back on parliament and walked out of the place. I think it’s a personal tragedy for him and a tragedy for the Labour Party, because a lot of what he stood for was right.”

The sense of betrayal in Harris’s voice is palpable. When Blair left, he says, there was no handing on of a cause, or belief-system within the party, everyone was left abandoned and Labour has suffered because of it.

“The money thing I just simply don’t understand,” Harris adds. “Living this strange life with the billionaire super-rich on private jets and yachts.”

Isn’t Harris’s pal Mandelson partial to a yacht now and then?

“Well yeah, but Peter is Peter. He's sort of always moved around society, as it were, and in a way that doesn’t make what has gone on with him since surprising. But Peter is the soul of plain living, frugality, compared to Tony Blair. He associates with the paupers of the earth compared to the people Blair associates with!”

As much as anything, it was a fall-out over the handling of Peter Mandelson that was behind Harris’s decision to split from New Labour. How amazed was he when Mandy came back under Gordon Brown?

“I was pretty surprised,” he says. “I mean Peter rang me from the car on his way to Downing Street and said ‘you’ll never believe what’s happening’. And I told him he must do it, because, you know, politics is completely in his blood.”

Mandelson understands the game brilliantly, Harris says. In fact he has the best political brain he’s ever encountered.

So far no mention has been made of another of Harris’s longstanding friendships – a man called Jeremy whom Harris met while working on Panorama in the 80s. Since announcing in April he was quitting Newsnight, Jeremy Paxman has – according to some observers – appeared rather bored on air, and very much ready to leave.  

“Well I’m afraid I never see Newsnight because I turn the light off at 10.30 so I can’t comment on any recent appearances,” says Harris diplomatically, before revealing it was partly his advice to Paxman which led to his decision to stand down.

“I think my advice to him was to give up more than a year ago, and I’ve nursed the secret for six months or more that he was going. Jeremy always says that I said to him, ‘Do you want to have it on your tombstone that you presented another 500 episodes of Newsnight?’ Apparently he kept coming back to that comment.”

A friend whose advice has influenced the careers of some of Britain’s best known figures; a bestselling author who also has an arsenal of tales from the political front line – surely it’s time for Robert Harris to write an autobiography?

“I can’t see it,” he says. “It would only happen if I run out of steam writing fiction. I don't think I've led a particularly interesting life.”

Driving back to Kintbury station in his Land Rover Discovery after the interview, he slows down to read a text. It’s from his older daughter who works in publishing. She’s getting in touch to tell him that the paperback bestseller list has just come out. “Apparently I’m at number three,” Harris says with a modest grin. 

Tags: Robert Harris, The Ghost, Tony Blair