Historian Jonathan Clark exudes an air of patrician gentility, but the feeling she arouses in his peers are not always so exquisite. Simon Targett talks to a controversial conservative.

Jonathan Clark looks comfortable beneath the chandeliers of Claridges. Diminutive, definitively home counties, neatly attired in a tweed jacket and sober Windsor-knotted tie, he settles back knowingly into a deep cushioned chair as a white-gloved waiter serves his order of the finest Lapsang Souchong in an elegant bone-china teapot.

And why shouldn't he? After all, everything about Clark suggests the classic corduroyed patrician Tory gentleman. A former Eton schoolmaster, a sometime fellow of two ultra conservative Oxbridge colleges - Peterhouse and All Souls - his list of recreations in Who's Who - hunting, shooting and fishing - as well as his Pall Mall dining club come straight out of the model toff's handbook. As if that were not enough, he has argued for the survival of the traditional ruling elite, identifying a British aristocratic ancien regime well into and beyond the 18th century - an argument so extraordinary that it has shaken from a historiographical slumber that sleepiest of centuries, once dubbed "an oasis of tranquillity".

But Clark's comfortable upper crust manner, recalling Benjamin Jowett's "effortless superiority", belies a sometimes bitter struggle for recognition in the peculiarly backbiting world of the professional historian. It did not help that he got off to a bad start when, after winning a place at Downing College in Cambridge in 1969, he slumped in his finals, missing his dreamed-of first. Leaving Cambridge under this cloud, he headed to the London Stock Exchange, taking up a traineeship with the stockbroking firm Pinchin Denny.

ÖйúAƬ

This rankled. As he later wrote: "Lecturers exuded the conviction (it never needed to be made explicit) that all their ablest pupils would of course 'do research'. A career in industry or the City was regarded with amused contempt as a sign of failure in the High Seriousness stakes." But the following year, he returned to Cambridge, registering as a student of the legendary professor, J. H. Plumb. Unfortunately for Clark, Plumb preferred the proven starred-first quality of such acolytes as John Brewer, David Cannadine and Linda Colley - and after a term he was assigned a new supervisor, Ian Christie of London University.

This effectively sealed Clark's fate for the next ten years. Although he was sheltered for a period by the conservative mavericks of Peterhouse, and notably Sir Herbert Butterfield - he has called himself Butterfield's "unofficial pupil" - he was a largely isolated figure. Out in the cold, "frozen out" as he puts it, he found himself at odds with Plumb and his circle, something which surfaced in a series of deliciously barbed footnotes. In one, he commented on Plumb's observation that in the 18th century "it was patronage that cemented the political system, held it together, and made it an almost impregnable citadel, impervious to defeat, indifferent to social change". This, Clark noted, "could more appropriately be applied to the workings of patronage in some areas of modern academic life".

ÖйúAƬ

In conversation, Clark chooses to skip over this period of his life, even though the resilience he must have shown in the face of disappointment would be applauded by any modern-day struggling academic moving from one temporary appointment to the next. A historian he may be, but he does not like talking about his own dim and distant past.

It is true, of course, that, in the end, he did triumph. The turning point was 1986. That year, he landed the fellowship at All Souls. It was an extraordinary almost Churchillian leap - akin to an out-of-favour politician suddenly being rewarded with a cabinet post. The reason for his success was English Society 1688-1832, his seminal work, published the previous year, which had turned him into an overnight sensation.

Far different to his first book - a voluminous but narrowly-focused account of high politics in the 1750s - English Society is a breathtaking intellectual tour de force. Sweeping across 150 years, Clark identifies, contrary to the orthodox view of creeping modernity, a "hegemonic" old order supported by the ancient pillars of monarchy, the aristocracy and the church, and comparable with pre-revolution France. Cambridge historian John Morrill, praising it as "brave", said "it breaks the mould of Hanoverian politics". John Kenyon, calling it "epoch-making", was forced to rewrite his classic text on great historians since the 17th century, The History Men, to take account of the Clark phenomenon. There, he said that Clark had "put a new spin on British 18th-century studies" and that it was "safe to say that they will never be the same again".

Given new confidence, Clark rushed into print with a second volume, Revolution and Rebellion, which mocked virtually the entire British historical establishment: the "Old Guard" Marxists like Christopher Hill, Eric Hobsbawm and E. P. Thompson; the "Old Hat" post-Trevelyan liberal historians like Plumb; and the "Class of '68" radicals like Edinburgh professor H. T. Dickinson. But it was poorly received. Although historians have always bickered furiously over apparently insignificant details - one famously acrimonious dispute raged over whether the pre-civil war nobles were rising or falling - Clark's ad hominem assault was viewed as beyond the pale.

At 35, he had become the enfant terrible of British history, and he was soon in great demand as a media don, his initials "J. C. D." becoming almost as recognisable as that earlier historian-journalist "A. J. P.". Writing on everything from royalty to the Beatles, he was the first of a so-called "brat-pack" of opinionated conservative historians which now includes Andrew Roberts and Oxford don Niall Ferguson.

ÖйúAƬ

You either loved him or loathed him, and All Souls found this out during Clark's reelection as fellow. Eighteenth-century specialist Joanna Innes, lecturer at Somerville, was asked to suggest historians who could provide an independent and unbiased opinion. Her response was swift: "You won't find anyone who is neutral on Jonathan". Even today, some historians find it hard to forgive Clark's torrent of venom. One Cambridge contemporary, learning of this article, replied: "Oh dear! Must you?" Another, at All Souls, bluntly refused all comment. "Look," he said, "I just don't want to talk about him."

The sensitivity at All Souls partly surrounds the rumours - published in The Times diary last year - suggesting that Clark was "moonlighting" in the United States. These were later retracted, but All Souls still felt a sense of wounded pride when, even though Clark was promoted to a senior research fellowship - which the college likes to think is equivalent to an Oxford professorship - he wandered off to take up a chair at an American university which is not even Ivy League and which is in the middle of nowhere.

Kansas University is where Clark now holds the Hall distinguished professorship of British history. To think of him there is strange. Not long ago, Oxford was, for him, "the centre". But nowadays, Clark seems a changed man. The confidence bordering on arrogance is still there - his 23-page curriculum vitae lists the fact that he "invented the 'long 18th century'" as a teaching concept in Cambridge. But there is an accompanying humour suggested by his tailor-made "from the desk of GOD" Post-it sticker pad. And, happily, there is none of the gloating, none of what he admits was "dancing on the graves" of the old historians. "That's all gone away now," he reveals. "I don't think it's so necessary to be aggressive anymore. I did think it was necessary in the mid-1980s to adopt that tone. Unless one did so, the message would not have got through. But now that it has, it is possible to be much more tranquil." Ten years ago, Clark was fighting what he calls "an ideological civil war" which he likes to think he won. Now, with the gentlemanly poise of the magnanimous victor, he suggests there is "a spirit of live and let live".

ÖйúAƬ

But if today Clark is more tally-ho than gung-ho, he is no less controversial. His second book, The Language of Liberty 1660-1832, seeks nothing less than to explain the origins of the American revolution. Published in 1994, it reinforced his revisionist impulse, his extraordinary intellectual range, and his growing fascination with the US that was first evident in 1990 when he co-drafted proposals for an American studies institute in Oxford and which was underlined earlier this year when he married an American academic.

It also reinforced his growing reputation for redefining the staid old subject of ecclesiastical history. English Society had highlighted the significance of religion, replacing the 1832 Parliamentary Reform Act with the 1830 repeal of the Anglican Test and Corporation Act as the final deed of the old order. His The Language of Liberty explains the American revolution in terms of sectarian divisions rather than class conflict or nascent nationalism. And this, the religious road, is the one he plans to follow - or, rather, pave - from now on. His next opus is provisionally entitled Providence, Chance and Destiny: religion and the conceptualisation of revolutionary change in England 1600-1800. It will be, he says, "part theology and part applied theology" which will establish "a new genre of ecclesiastical history" showing how the world view of ordinary people back then was indebted to a "providentialist matrix".

Meanwhile, he is preparing a second edition of his English Society in a way which testifies to this new direction. Retitled The Anglican Ascendancy 1660-1832, it will detail the role of religion in the restored regime and discard the iconoclastic historiographical introduction which caused such a storm ten years ago. In the long run, it could form the first volume of an epic trilogy, with the second volume a revised The Language of Liberty and the third volume a study of England in the British context. As he now confesses, English Society "was an account of the hegemonic state of the Southeast of England".

This project remains a distant one. On the other hand, it is one which he is likely to see through to the end. J. H. Plumb, whom he has long seen as his bete noir, has still not finished the trilogy on Sir Robert Walpole he began 40 years ago. When it was pointed out that an unfinished trilogy would mean him having something in common with Plumb, Jonathan Clark was quick to respond. "Well," he said, with a smile he might not have managed ten years ago, "I'd better make sure that I finish it then."

ÖйúAƬ