BOOKS / A revolting obsession: 'History is fiction,' said Robespierre, who knew how it would treat him. Is the novelist better equipped than the historian to find human truths behind the mask of 'fact'?

Writing a novel in English about the French Revolution is a bruising enterprise: you are trapped in some ghostly boxing-ring with Dickens, and with Carlyle who provided Dickens with his best effects, and with Baroness Orczy, and with innumerable writers of romances about picturesque aristocrat victims. George Orwell said 'To the average Englishman, the French Revolution means no more than a pyramid of severed heads.' In his essay on Dickens he writes that A Tale of Two Cities is largely responsible for the English reader's picture of the time; 'He gives the impression of a frenzied massacre lasting for years.'

Even if we know better than that, there's a tendency - which many historians share - to regard the Revolution as a gigantic blunder. If it was a mistake, it was one that many of us - had we been alive at the time - might have found convincing. Historians pass judgement, employ hindsight; but hindsight distorts. Novelists don't need to employ it; their narrative pushes forward, against the grain of scholarship, which is always analytical, considered, retrospective. I sometimes feel, therefore, that novelists can get nearer the truth. This notion, anyway, has sustained me through the long lifetime of this manuscript - a life that has occupied about half of mine.

I began this book in 1974, when I was 22 years old. With hindsight, I know the project was insanely ambitious. But I had been thinking about the Revolution since I was 14. I am perhaps the only person who has been simultaneously head girl of her convent school and a member of the Young Communist League. I was in love with politics, and I thought you had to understand revolutions to understand anything. Not all of us take part in political revolutions, but we all go through a psychic revolution, when we overthrow the old regime of our childhoods. What famous people do on the larger stage we all do within ourselves - revolt, reshape, redefine, try somehow to make a world we can live in.

I can't say that, myself, I succeeded, because when I began writing I wasn't living in a world that suited me. Yet I was creeping closer to my future characters: I was a lapsed Catholic, and a sort of lapsed law student who didn't believe in my ability to turn the law into a career. One evening I began to take notes from the historian I was reading at the time. I remember wondering what I was doing. I supposed I must be writing a novel, but I had been told you needed imagination to write fiction, and I didn't think I had much. Sometimes I had tried to write a short story; it would stagger on for 10 pages and then fall over. Besides, I had no interest in making things up. However - like Edward Gibbon, but sillier - 'Unprovided with original learning, unformed in the habits of thinking, unskilled in the arts of composition, I resolved to write a book.'

I didn't want to write any other book - just A Place of Greater Safety. So why have I published four other novels before this one? Life kept throwing up material which made its own demands. The real book gathered dust, till the spring of 1991: but that's another story.

My three main characters are Danton, Robespierre and Camille Desmoulins. It was a good choice, I think. Danton is an irresistible subject; a rise-and-fall story is the best there is, and in his case it takes the classic form, both inspiring and frightening. Charisma is hard to put on the page, but his immense ambition is perversely attractive. At best, Danton took money for doing what he was going to do anyway. At worst, he was totally corrupt, a cynic, a chancer on a massive scale. But he was deeply intelligent and, in my narrative, self-aware: the last few days of his life show a man horribly conscious of his tragic status.

Camille Desmoulins was a lawyer turned mob-orator turned journalist. He met Danton before the Revolution, but he had known Robespierre since childhood. He performed the difficult feat of being a close friend of both. Camille was one of those people who become emblems and lose their surnames. He is the archetype of the mischief-maker, the wrecker; the Revolution brought him the fame he craved, and also money, and also endless opportunities for behaving badly. He was clever, impulsive, and could make Robespierre laugh. If you follow his career you can't fail - whatever your political bent, however profound your philosophical detachment - to enjoy the Revolution a bit.

Perhaps it is Robespierre who turns out to be the most interesting of all. Over the years, writers have found their imagination seized by his battle with Danton. They see a contest between the sensualist and the priest, the farmer and the bureaucrat, the natural rebel and the man who wouldn't (if he were alive today) cross the road when the red man was showing.

But, day to day, it wasn't like that; not, at least, until the end of their lives. I see two men with some unwilling sympathy for each other; their ideals bringing them together, but their style driving them apart. To the average English-speaking reader, Robespierre is a monster. But here you're dealing with the Richard Crookback phenomenon - history written by the winners, creating an image of the loser as not just morally but physically repellent. 'History is fiction,' Robespierre said. He knew how it would treat him.

He began his career as a gentle, rather unworldly young man, with a vein of self- deprecating humour. He was a pacifist, opposed to capital punishment, who fought impeccably liberal campaigns against slavery and anti-Semitism. How did he turn into the frozen idol of the Revolution, the architect of the Terror? And what did this inner revolution cost him? Long before he entered public life, he wrote that 'Every citizen has a share in the sovereign power. . . and therefore cannot acquit his dearest friend, if the safety of the state requires his punishment.' But when Desmoulins opposed the Terror and defied the Committee of Public Safety, Robespierre stood at the tribune of the Jacobin Club and wept: they could not harm Camille, he said, because 'Camille is a child'. His best friend chose to die in other people's company: it was, perhaps, the ultimate rebuff. After Camille's death Robespierre lived three months.

What people are going to ask is this: how close to fact is this book? The real question is, what kind of facts do you want?

Yes, we know the date on which Louis XVI was executed, the date the Bastille fell. But if I say that on the day the Bastille fell the price of bread had reached its 300-year high, what kind of fact is that? Is it a vital contribution to understanding? Or simply the kind of snippet an old-fashioned Marxist might like to find in his Christmas cracker? Matters of fact shade over into matters of interpretation with frightening ease. Why did the Revolution happen? Was it necessary? There are as many answers as there are people to ask the question. All you can do is pick a version, and, as a novelist, look for what is useful for the purpose of making sense and finding a pattern.

I have chosen to write about characters who began in obscurity. Their early lives were barely chronicled. We know about the death of Robespierre's mother, when he was six years old. We know that the infant Danton had a dispute with a bull and that he was later trampled by a herd of pigs. But we don't know when Camille Desmoulins developed the speech impediment that seemed to have ruined his life - until he discovered that, when he had to talk to a mob, he did not stammer at all.

When you have gone through the small documentary evidence - baptismal certificates, lists of school prizewinners - you are left with rumours and local gossip. And the occasional lucky break, the novelist's gift from God. Fabre d'Eglantine - poet, crook and landscape gardener, designer of the Revolutionary calender - was Danton's sidekick when Danton ran the country. Did they first meet when Danton was 17? Probably not: but for a few weeks they were in the same town. As neither was the type to go unnoticed, even a fettered imagination like mine can allow them to run into each other.

After my people become famous, we know a fair amount about what they thought on this topic and that: what speeches they made, what votes they cast, and so on. We still know next to nothing about their private lives and private thoughts. Why did they act as they did? They didn't have time to explain. Robespierre was 35 when he was executed. Danton was 35. Desmoulins had so recently passed his 34th birthday that (to the bewilderment of historians) he forgot about it and gave his age to his interrogators as 33.

In my book I've tried - without claiming to say anything new - to explore the political process in a dramatic form. In revolution you have minutes to come up with the answers to problems which have taxed people for centuries - this is especially true of the French Revolution, which is the template of the modern world. My people started out by seeing political activity as a means of fulfilling human potential - Danton said 'After bread, education is the people's greatest need' - but they must soon have suspected that politics is at best an exercise in damage limitation. Saint-Just wanted a regenerated society, and believed passionately in the possibility of making one (though few people would have wanted to live in it), but Robespierre's private notebooks indicate the growth of a crippling pessimism. Camille Desmoulins said: 'I dreamt of a republic that the world would have adored; I could never have believed that men could be so ferocious and so unjust.'

Of course, one must write about this disillusionment, but I wanted to write about the dream, too; to imagine what it might have been like to wake up the day after the Bastille fell, and believe that a new world was in the making, and that you were going to make it.

I have tried to use people's actual words when I can, fitting my own dialogue around them. I have not tried to give any kind of overview of the Revolution. I write about my characters during their provincial childhoods, but thereafter my version is Paris-based, takes no account of the Revolution in the provinces and very little account of the Revolutionary wars. I haven't tried to be even-handed. For instance, it is possible to make a case for Louis XVI as a fair, wise, responsible ruler - and indeed, when he came to the throne, Robespierre for one thought he was just what the country needed. But my people came to see the king as a fool, and then as a treacherous fool; it is not my place to tell them they were wrong. And I have tried to let my people have their say about each other, in some cases, by apportioning them bits of the narrative.

I have sometimes worried that the book is a quaint and nave undertaking. The biographical approach to history became unfashionable many years ago, but a novelist must focus on individuals, and how they live together and what they think of each other; I don't know how, when I was 22 and (still) fairly much a Marxist, I reconciled this bourgeois approach with my more austere perceptions of the historical process. But even then I saw that people's characters are important: the Jacobin cause was not helped (for instance) by the fact that the mayor of Paris believed that the king's sister was in love with him, or that Manon Roland, an influential woman, made her husband's colleague Danton the focus for a lifetime of sexual fear. Such perceptions may not be a historian's business, but they are a novelist's business.

Faced with something bizarre, inexplicable, a historian can only throw up her hands and say 'God knows why.' But a novelist need never throw up her hands. She can go on enquiring, proposing versions, trying out scenarios, finding a context, a plausible explanation. Above all, she can say: 'I know these people are dead, but I tell you they are real, they lived and breathed like you and me, and it is my duty and privilege to supply or create a private context for their public behaviour.'

In one sense I have no large aim - I would not presume to instruct the reader in historical events or what to think of them, or suggest whether to apply the lessons of the Revolution to our own day. In another sense, I do have a large aim, because I think more highly of the uses of fiction than I did when I began work. I've been lucky: in a way, my people have written my book for me: their lives were short, dramatic, painful, entertaining. As a guideline for the reader, I can proffer this: whatever seems most unlikely in this book is not made up by me. I have tried to serve the facts, as they are known and agreed. And I have tried to write a book that my readers can live and think inside, and which will please them, and touch their hearts.

'A Place of Greater Safety' is published by Viking, price pounds 15.99, on 3 September.