Who let in the historians? The scene is in central London, the leavings of a fine dinner scattered across the tablecloth. One of the men at the table has been the best known and most mocked world leader of the current era. Another, circulating quietly, patting arms and murmuring pleasantries, is the British prime minister. But what of the rest? Over there is the long, mobile, slightly dandyish figure of Simon Schama; nearby, with her customary half-smile and slightly intimidating poise, is Linda Colley; there's the bull-like Sir Martin Gilbert; the lanky, somewhat Bloomsbury figure of David Cannadine; and the short, fair-haired young Napoleon of the trade, Andrew Roberts. Five historians, then; but what's the connection?

They have sold many hundreds of thousands of books, shaping how we understand the world. Their work sprawls across the last few centuries of British history, but they reach into Dutch, Indian, American, Israeli and European history too. Two of them, Colley and Cannadine, are married to each other. One, Schama, is a television star. They are of different ages, from the great Churchill biographer Gilbert, born in 1936, to the Churchillian revisionist Roberts, born in 1963. They cross a wide political spectrum.

The connection, if you haven't guessed, is that they were all invited by Gordon Brown for a private dinner with George Bush at Downing Street earlier this year. Bush remarked that the group photograph would be his Christmas card.

History is sexy. Once, the guest list for a glitzy political occasion would have included a rock star or two, a television host, a clutch of well-known business faces and perhaps, barely tolerated in the corner, a tame intellectual. So, to start with, let's celebrate a moment when proper historians were brought into the inner circle and treated with respect. Brown has always been fascinated by history. He talks a lot in private about Colley's books, and Schama's. Bush has reached the moment when he is starting to wonder, perhaps with a shiver of apprehension, what historians will make of him. He is famously fascinated by Churchill and has read Roberts's latest big book on the English-speaking peoples. Unlike Churchill, he is not expected to write the history himself, but he is already looking for a suitable official biographer, and Roberts is on his list.

What was interesting, though, was Brown's guest list of historians. (There were more there, but those are a representative selection.) Gilbert was an essential booking. Roberts, like Niall Ferguson, is a star of the conservative epic-sweep school of young historians who have broken through in the American market. Both have engaged politically through counter-factuals and polemic. They answer a hunger for patriotic, optimistic narrative on both sides of the Atlantic.

So far, so obvious. But Brown would have been a laughing stock had he confined his guestlist to them. As we struggle to understand today's world, the epic conservatives are selling stacks of  books and often seem to dominate as television pundits. But they are challenged, particularly in Britain, by rival schools that are also now hugely popular.

There are the social historians, often flavouring their accounts of modern times with personal experience. Under the friendly if magisterial wing of Peter Hennessy, Queen Mary's, at the University of London, has become a seething hotbed of popular and contemporary history. Working on a radio programme of ideas, "Start the Week", I've been struck by the quality and quantity of "Hennessy school" historians emerging, as compared, say, with what is currently happening in Oxford and Cambridge.

Then there are those writing great-sweep history with a liberal and questioning tilt, more accessible and less miserabilist than the old Marxist school. They tend to highlight migration and challenge notions of national destiny. Schama, a riotous debunker from his earliest days, is one such. Both Colley, whose epic work on the creation of the "British" story has been followed by surprising tales of empire from below, is another. Cannadine's great book on the decline of the British aristocracy puts him in the same company. Many others can be added--Lisa Jardine on Dutch-English relations, for instance.

Like their conservative rivals, these historians have found ways back to the great old-fashioned narrative-popular writing that comments directly on the kind of nations Britain, and America, have become. There is a battle of ideas going on-a quiet, gentlemanly, nuanced battle, but a battle nonetheless. Read Roberts or Ferguson and you see today's world one way. You are more optimistic about the next American century, more bullish about Western military intervention. Read Schama, Colley and Cannadine, and your vision is likelier to be of a more unstable, polymorphous world in which today's elites may claim power but which is being transformed in ways they do not and cannot understand.

People often ask, where are the big ideas? What has happened to the stories through which we understand ourselves? The novelists have drawn in their horns. Big stories rarely emerge through the blandness of politicians' books or the think-tanks' social engineering manuals. Even Barack Obama's historical sweep is pretty bland. But turn to the history section of Water-stone's or Borders and there's a vivid, bubbling conversation going on, as interesting again as intellectual life was in the 1960s, or Edwardian times. 

Illustration by Harry Malt: photograph by Sam Barker

(Andrew Marr presents "The Andrew Marr Show" on BBC1 and "Start the Week" on Radio 4. His "History of Modern Britain" has been a bestseller. He is a former editor of the Independent.)