John Walsh: Tales of Hay-on-Wye

'Rumours are flying. I'm told in high seriousness that Posh Spice is here, specially invited by Gordon Brown'

Outside it's bucketing down, real lashing, pitiless Welsh rain, the kind of torrent that stirs writers to elaborate metaphors about cleansing and redemption, and sends everyone else scurrying for the beer tent, the smoked-salmon-and Moroccan-lamb restaurant, the urgent glass of wine at 4pm. The car park is under water, the 4x4s up to their bumpers in ochre mud. Book-festival cuties called Clemency and Ellen, all in green Hunter gumboots, cheer each other up with cries of "Never mind, darling - think of Glastonbury!"

In the Green Room, the Talent are sheltering from the rain, thawing out from the wind, fighting off the cold. Some have brought no jumper or sensible jacket (have they been to Hay before?) They're the most eclectic bunch of literary and media persons. The cast of Radio 4's Just a Minute is in, and Nicholas Parsons, still wearing candy-striped, golf-club-secretary jackets in his eighties, is standing beside Wole Soyinka, the wild-white-haired Nobel Prize-winning playwright. Felipe Fernandez-Armesto, awesomely learned historian of the millennium and chronicler of Amerigo Vespucci's voyages, drinks tea beside the wheelchair of the spade-bearded Robert Wyatt, former drummer of Soft Machine. The scriptwriters of Casino Royale, Neal Purvis and Robert Wade (whose proud boast is that every page of their script, whatever was on it, cost the producers a million quid) are incognito, which cannot be said for Simon Schama, or Maureen Lipman.

Billy Bragg, the shark-lipped troubadour of Old Labour in the days of Neil Kinnock and Red Wedge, is looking serious and unmusical as he prepares to discuss the nature of democracy and the erosion of civil rights with Henry Porter, John Kampfner of the New Statesman and Philippe Sands QC. Antonia Fraser is leaving after her session about the love affairs of Louis XIV.

Can the modest-looking cove on the sofa really be Neil MacGregor, director of the British Museum? And whatever is it (look at Paul Merton and Dara O'Briain) that makes modern comedians so unfeasibly tall? On Saturday afternoon, when Gordon Brown came a-calling, the Green Room was policed like a royal visit, and rumours flew about who else was present. I was told in high seriousness that Posh Spice was there, by special invitation of the new PM...

It's the nature of literary festivals to fling together heterogeneous combinations of people (staff at Cheltenham still speak of the time in 1988 when Edward Heath and the drug-smuggler Howard Marks found themselves alone together); but Hay this year deserves a medal. "It's getting ridiculous," said Libby Purves. "Like some crackpot version of the cover of Sergeant Pepper."

Many festival stars do much more than turn up and chat about their book. Richard Dawkins clearly welcomes the chance to take on religious-minded folk, listen to their arguments and explain - kindly, but with great precision - that they're wrong logically and they're fundamentally imbeciles. His session was full of special pleadings from non-atheists, like doomed martial arts amateurs lining up for a crack at Bruce Lee.

Can science explain exactly why the Earth exists? "No, but that doesn't mean God is the answer." Aren't our feelings of wonder - looking at the Milky Way, say - promptings of religious feeling? "No, they're just wonder and awe. Einstein felt the same, and dragged in the name of God, but he was guilty of a category error." Shouldn't religion be taught in schools as Intelligent Design, a branch of science? "Only if you give equal time in class to the Flying Spaghetti Heroes or the Nigerian theory that the world was created from the dung of ants."

Dawkins was relentless. Without religion, wouldn't we be living in a grim, quasi-Communist amoral non-society? "Nah," said Dawkins, "wherever our notions of morality come from, it's not the Bible, or we'd still be stoning people for picking up sticks on the Sabbath." Aren't your views a little too cruel to the terminally ill? "No, if I met a terminally ill patient, I'd talk about the weather..."

Dawkins is so steely that it's hard to wrong-foot him. But it happened. He'd poured scorn on the Archbishop of Canterbury and all "nice archbishops" for making the world safer for terrorists by saying it was a marvellous thing to believe something in the absence of all evidence. OK, then, asked a lady, do you think the Archbishop is a deluded, foolish man? "You put your question with merciless clarity," said Dawkins, impressed. The answer? "I think he's very bright. And I'm absolutely baffled about why he believes in God." Hah! Chalk up one to the Almighty.

Africa was a theme of the festival - its literature, Wole Soyinka, Kenyan novelists, Heart of Darkness, the white man's burden - but was nowhere brought to life more vividly than when Dave Eggers introduced Valentino Achak Deng, a young Sudanese man, who was one of the Lost Boys - 3,800 orphans endlessly shuttled around Kenyan and Ethiopian camps after losing their families to the Sudan war since 1983, and finally housed in American refugee camps.

Eggers has written his story, and it's a document of the utmost power. Valentino was six when he started walking away, endlessly harried and terrorised by militia. Strange how the familiar recital of burning villages, rape and evisceration, terrible as they are, don't tweak the heartstrings as much as Valentino's story of how the Lost Boys, when processed as refugee children, were all assigned the same birthday - 1 January, as if their lives were at Ground Zero - and now meet for a birthday thrash every year. This was a moment when the sophistications of writing and the rawness of real life wrestle for the upper hand, and the latter won.