Hilary Mantel: ‘I’ve got quite amused at people saying I have writer’s block. I’ve been like a factory!’

About 15 years ago, Hilary Mantel got on a plane to Russia, on a cultural visit to Perm, near the Ural mountains. I was part of the group. As we readied ourselves for the flight, she explained that she’d be quiet for the next few hours; she was planning to immerse herself in a new project. It was, she explained, set in Tudor England, at the time of the great break with Rome, and featured both Henry VIII and his notorious chief adviser, Thomas Cromwell. And so if we would excuse her, she had lots to do.

Now, here we are, in the author’s home in the genteel Devon seaside town of Budleigh Salterton, with more than 1.5m copies of Wolf Hall and Bring Up the Bodies sold and the conclusion of her epic trilogy, The Mirror & the Light, sending pre-orders through the roof. The two Booker prize trophies that Cromwell has already brought Mantel perch unobtrusively on a bookcase and there are few signs of the immense industry that the enterprise has required – perhaps because Mantel sets off each morning for a small flat up the road in order to write, working on stage versions and an illustrated companion to Wolf Hall. Back in 2005, could she have imagined what lay ahead?

“No,” she replies, levelly. “I thought one book, five years. I didn’t think it would be quick. But I didn’t see how it was going to unfold from the middle in the way it did.” As she went deeper into her researches, she found multiple stories began to emerge, “each one of them worth a book. There are so many novels enfolded in the novels that sometimes, I wonder – well, it’s a pamphlet compared to what it could be.”

At a combined total of more than 2,000 pages – with The Mirror & the Light accounting for nearly half of them – you couldn’t get much further from a pamphlet. “I’ve got quite amused at people suggesting I have writer’s block, you know. I’ve been like a factory!” She also chafes at the suggestion that her latest book was delayed because she was reluctant to kill off Cromwell. “It’s not something I’ve ever said; it’s what people think I should have said. It’s this version in which the woman writer is sentimentally attached to her creation. As opposed to the male writer who just wants his cheque.”

More remarkable than the trilogy’s size is how Mantel has taken what many of us know only from our schooldays – Henry’s prodigious appetite for serial marriage, the brutal fall from grace of Anne Boleyn and the religious turmoil into which England was plunged – and made from it one of the most subtle and sinuous character portraits in contemporary fiction. In her hands, Cromwell is a shape-shifter: the brutalised boy who disappears into the cosmopolitan whirl of continental Europe and returns to work his way to the heart of the Tudor court. And the books that tell his story are, she tells me, “about all the big important things that matter, about sex and power and high politics, statecraft and forgery and delusion and lies”.

Mantel had the idea for Wolf Hall before she was ever published. “As soon as I started writing, I knew this was what I’d been working towards,” she says, “that confidence right at the beginning of having arrived where I should be.” But surely having written 10 novels, including A Place of Greater Safety, her vivid exploration of the French Revolution, and Beyond Black, the tale of mediums in middle England that immediately preceded Wolf Hall, she had experienced that feeling before?

“Not the absolute rightness, the congruence, between author and subject, that I felt with the first paragraphs of Wolf Hall,” she says. Later, when we are drinking tea and looking out over the horizon, she says that starting the trilogy was “like at last delivering what’s within you … an enormous shout from a mountaintop”. This is not to disavow her previous books, though she is shrewdly droll about her status in the world of publishing. “I had reasonably healthy sales with Beyond Black and that was for the first time. I’d had good reviews always, but no sales. And I felt very much like a niche product, you know, very much a minority interest.”

Mantel has always had a canny understanding of the business of writing. A Place of Greater Safety was the first novel she wrote: “I just thought of myself as a historical novelist, and I thought, do the French Revolution, and then do Thomas Cromwell. And then I couldn’t get that first novel published, so I started writing contemporary fiction. And then I learned that I wasn’t just a historical novelist. But it was there, all the time.” Those early novels, beginning with Every Day Is Mother’s Day in 1985, and looping through Vacant Possession, Eight Months on Ghazzah Street, in which she drew on time spent living in Saudi Arabia, and An Experiment in Love, explored among other things the troublesome double-binds in which women frequently find themselves. Those narratives’ vexed interest in the desire for personal freedom and self-creation, and their preoccupation with class and circumstance, is clearly related to the fascination she has for Cromwell.

“If you look at a tragedy like Othello,” she says, “there used to be all that lit crit stuff about his fatal flaw and so on. And now we can see his problem is he’s black. Structurally, there’s a built-in decisive disadvantage. It doesn’t matter what kind of person he is and what decisions he makes. And I think with Cromwell, you’ve got the equivalent that he’s starting out from the wrong place. So what he does achieve every day seems like spitting in the eye of the pattern laid down. You have to understand, the 16th century is a time when ambition was a dirty word, because it was like being cheeky to God.”

In Tudor England, it wouldn’t just have been the nobles who wanted low-born Cromwell to know his place, she says, but the general populace as well. “They were saying we don’t want to be ruled by people like that, we want to be ruled by the nobs, the equivalent of Old Etonians, Jacob Rees-Mogg.”

Mantel was fascinated to find in her research that the idea of the English that we associate with the stiff-upper-lip cliches of the Victorian era were far from the way 16th-century Europeans viewed them. “They thought the English were kind of berserkers: first of all, they spoke a barbarous language that no one could understand; and then they were really impious and they were extremely violent. So it was like a nation full of old-style football hooligans.” She also became convinced that, at the time of the break with Rome, one of Wolf Hall’s chief characters, Cardinal Wolsey, was determined to move England closer to Europe and to enhance its power; Cromwell himself saw the schism as a way to broker an alliance with Germany and Scandinavia that would reconfigure the whole power structure of Europe. “So that’s a kind of picture of Europe with which we’re terribly unfamiliar and yet it could have happened.”

It is clear from the way Mantel talks about Wolsey and Cromwell the emotional connection she feels with them. “I love Wolsey,” she laughs, “because he enjoyed it all so much. I know all the reasons for thinking badly of him but I can never be quite persuaded. And I absolutely understand why you’d be englamoured by him. And also he seems to me to have been a man with a heart and I can quite understand Cromwell’s long loyalty to him.” As for Cromwell, it is the sheer chutzpah of his self-invention that appeals. “One of the things I’m really exploring is the universal question of what’s luck? What’s fate? Does anybody make their own luck? How far can you write your own story? And he’s someone whose whole career ought not to be possible. But at some point in early middle age, he just grabs the pen and starts writing it.”

It is, perhaps, an experience to which Mantel relates. Her memoir Giving Up the Ghost tells the story of a fractured upbringing in Derbyshire (“My childhood ended so, in the autumn of 1963; the past and the future equally obscured by the smoke from my mother’s burning boats”, she writes of her parents’ split and her mother’s remarriage) and an emergence into adulthood marred by serious illness, ignored, disbelieved and misdiagnosed. For severe endometriosis, she was prescribed anti-psychotics; at 27, she describes “having my fertility confiscated and my insides rearranged”. One doctor, for reasons unexplained, but with more energy to his statement “than any I had heard him make”, told her not to write. Racked with pain and filled with drugs, her body swelled; and periods of severe and debilitating ill health have recurred throughout her life, as chronicled in her 2010 hospital diary, Ink in the Blood.

Along with pain and physical disintegration, ghosts stalk her work. “I do have the sense of it being a very proximate world,” she says. “And sometimes the barrier seems like an enormous stone wall and sometimes it’s just whisper thin. But you can be misunderstood in talking about it. Because none of it can be literal. It’s all just a series of metaphors.”

In Giving Up the Ghost, Mantel interrogates the question of whether she should be writing about herself at all. “I suppose the topic of censorship and self-censorship has always loomed very large for me,” she says. “What are you allowed to say and who is allowed to say what? And I have taken these books as a kind of project of territorial expansion because they’re right on the central ground of Englishness. Which, as I said in the memoir, I didn’t feel I possessed. I wondered where was this England? Because it didn’t seem to be where I was growing up.”

She describes Cromwell as a man who rises without trace, and who imparts animating energy to everything he touches. Mantel, too, combines a certain fragility with a distinct pugnaciousness. Between Bring Up the Bodies and The Mirror & the Light, she published a collection of short stories, The Assassination of Margaret Thatcher; in the title piece, she imagined a woman whose flat is infiltrated by a man determined to kill the politician for the wrongs she has visited on Ireland. It caused, perhaps predictably, so much outrage that Mantel felt “that we’d taken off into the territory of farce when people were suggesting that the police be brought in over the fictional killing of a dead woman”.

Now, she says, she’d like to turn the story into a stage play; despite her workload, she’s got “a big box of material”. Is she worried about poking the sleeping bear? She bursts out laughing. “It will be offensive on a scale like they’ve never seen. I shall be absolutely revelling in my capacity to give offence. So whether it will come to fruition or not, I don’t know. But I’m not going to be intimidated by those people.”

In a speech in 2013, Mantel referred to Kate Middleton, by then the Duchess of Cambridge, as “a jointed doll on which certain rags are hung”; a woman whose primary purpose was to provide the heir apparent with heirs of his own. Both Ed Miliband and David Cameron voiced their disapproval but, “if anything,” she says now, “I think my plea was to consider, these are human beings. I’m on her side, not one of her persecutors.” With the royal family yet again in crisis, she connects the current obsession with royal bodies to the themes she’s probing in The Mirror & the Light: “What is a king? Is he a sort of super-being? Or is he a kind of beast? Does he even rise to the status of human? And all this is explored through Henry’s body. So it’s very much a theme I’ve been conscious of continually. And, of course, it was completely misunderstood by numbskulls.”

Mantel’s husband Gerald, a geologist who now manages the many moving parts of his wife’s working life, is ready to drive me to the station. We speak, finally, of the pleasure and opportunities that working on the stage and TV adaptations of Wolf Hall and Bring Up the Bodies have given her. “You can reach a point in your career as a writer, mid-career or a little bit beyond that, where actually you’ve got good at doing something so you just do it. Sometimes you need to refresh your practice. I think that’s what the plays did for me. It was the boost I needed to rethink the possibilities of how to work.”

At 67, she knows that she won’t tackle another project on the scale of the Tudor trilogy (“it’s just maths, really”). But while she’s been writing it, there are other projects she’s put on hold, “all put away in notebooks and if I had the energy and concentration and the will, I could pull half a dozen books out of the cupboard, like the conjuror pulling handkerchiefs.” At other moments, she thinks, “Are you mad?”

In the meantime, what she’d really like is a fortnight off. “Or better still, a month. Just think of it. I could remake myself. And I would then be ready to go with all sorts of things. I’ve always known, even with my physical health, that it takes very little time for me to be sorted out and on the go again. I’m very sort of bouncy in that way.” Is there much point of winning two Booker prizes if you can’t have a month off? “Well,” she says, thoughtfully, “it’s a good question isn’t it?”

• Hilary Mantel will discuss The Mirror & the Light (4th Estate) at the Royal Festival Hall, London, on 6 March. southbankcentre.co.uk