Sitting in the Robbie Williams gridlock for about three days trying to reach Cambridge - how was I to know Knebworth was on the A1(M)? - fuelled a catalogue of conspiracy theories. What more apposite metaphor could there be for big, bad mass-marketing screwing over the honest, down-to-earth music of the people? Why are they queuing to see him when Eliza Carthy's on a few miles further up the road?
My grumpiness was scarcely alleviated when I arrived at the festival to discover that one of the weekend's main attractions, Linda Thompson, had cried off with throat problems, to be replaced by Fairport Convention, and for a long time artists and audience alike seemed to be paralysed in a heat haze.
Still, after 39 years in the charming surround of Cherry Hinton, the Cambridge Folk Festival didn't get where it is today without flogging a few pointy hats and frisbees, and it ultimately responded to its duty as flagship for alternative pop culture.
In a year offering an unusually lightweight bill, devoid of big-shot Americans (the interminably dull Rosanne Cash and the merely interminable Steve Earle were its star offerings), the largely unheralded home guard responded robustly to the occasion. The fast-rising duo John Spiers & Jon Boden were here, there and everywhere with their enlightened take on the English tradition, before joining Eliza Carthy for her keynote Saturday night set on the main stage. The gig affirmed Carthy's pre-eminence, established by her Mercury-nominated Anglicana album. On another stage Carthy's original recording partner, Nancy Kerr, was demonstrating the massive strides she's made both as a singer and fiddle player, in company with the fine Australian guitarist and singer, James Fagan.
Outshining the lot of them, though, was the prodigal guitar maestro Martin Simpson, who chose a largely blues-fuelled set of such velocity that it boomed out across the main stage, yanked the sunbathers bolt upright and, in the sweltering heat, sent shivers down our spine. The defining moment of the whole week- end was Simpson's furious, emotionally charged delivery of the early Dylan classic, "Masters Of War". "I first heard it when I was 14 and it frightened me to death," he said. "It frightens me to death that it still needs to be sung."
Even the Senegalese comeback kings Orchestra Baobab - whom you'd have thought would have been the hit of the weekend, with their sensual West African dance rhythms - had trouble matching Simpson's passion. The audience sashayed around with big smiles on their faces as Baobab rolled back the years, but in a huge marquee in leafy Cambridgeshire, the band lacked the irresistibility you might expect from them at a club in Dakar.
This festival has developed an alluring habit of taking left-field rock stars and turning them into unlikely folk godfathers - Nick Cave produced one of the greatest Cambridge sets I've ever seen a couple of years ago - and we were well primed for this year's joker, the ex-Teardrop Explodes anti-hero Julian Cope. "I'm the ultimate folk singer," he guffawed scarily, in full Rasputin garb, shades, hood, Jesus beard and all. He proceeded to entertain hugely with his constant wanderings around the stage, rambling introductions, surreal banter and a painful indecision about what to play next that made Badly Drawn Boy look like Robbie Williams. Occasionally he ruined it all by singing, but for a while Planet Cope reigned, and they were raising a glass in his honour later in the Not The Jesus Tent.
Kate Rusby made an unscheduled appearance, guesting during her husband John McCusker's fiddle set, with the Scots accordion legend Phil Cunningham. Young Irish/New Zealand band Gráda made a lot of friends; and you knew exactly when Yonder Mountain String Band were playing by the whoops and hollers that followed their post-O Brother, Where Art Thou? bluegrass through the various tents.
I retired to the cool of the Radio 2 stage to survey the event's dying embers - and saw the best two bands of the weekend. Despite a painfully obsequious introduction from Bob Harris, the Australian band The Waifs delivered a vibrant, feel-good set of rare wit and warmth.
But Oi-Va-Voi were something else again. Their sound was a wild, bewildering, enthralling mix of jazz and Jewish and Eastern European dance music, and their deluge of ideas left you breathless with wonder. And that's when they brought on their trump card, the astonishing young singer KT Tunstall. Robbie Williams would have loved it.