“It’s hot as a witch's tit in this room,” says Club UNCUT headliner Jesca Hoop. “I’m going to have to retune my guitar real quick… cos it sounds like a witch's tit. So if you’ve ever wondered what a witch's tit sounds like, then this is it.” Today has been the hottest day of the year so far in the capital. Despite the welcoming evening cool outside, temperatures in the newly-refurbished Upstairs At The Garage in north London are unforgivingly high. But in some respects, you couldn’t have wished for a better line-up at Club UNCUT in heat like this. White – the daughter of a folk singer and sculptor who spent some of her childhood on a hippie commune in Northern California – brings a breezy, ‘60s coffee-house vibe to her songs, while Hoop, as perhaps befits the former babysitter of Tom Waits’ children, can be a little more leftfield with her melodies. But both of them have a beguiling charm that goes some way to soothing the otherwise punishing heat in here tonight. Simone White, opening for Jesca, at least has the foresight to wear a light summer dress, as opposed to Hoop’s long-sleeve lace number and a knee-length skirt. All the same, she still finds the time to reflect on the differences between American and European air-con systems (the result? We loose). “I’m melting up here,” she gasps, before shrugging: “It’s OK. It’s good for the vocal chords.” It’s possible you caught White live on last year’s Honest Jons Revue, performing on the same bill as label boss Damon Albarn, Tony Allen, Candi Staton and Victoria Williams, or heard her “Beep Beep Song” on the soundtrack to an Audi car commercial. Tonight, just her and a guitar, her voice reminds me sometimes of the smoky softness of Suzanne Vega or Cat Power; she sings very quietly, yet with incredibly precise annunciation. Although the songs themselves appear gentle and graceful enough, you sense they address more significant issues. She introduces “Great Imperialist State”, from her 2007 album I Am The Man, as being about “the disconnect between the things we consume and where they come from”. There’s songs, too, about her grandmother “a singer and dancer in the 50s” (“Mary Jane”), the shocking antics perpetrated at a teen party “dropping white pills into pink lemonade” in “Candy Bar Killer", and an 80 year-old woman she knew who wanted to die (“A Girl You Never Met”). White and Hoop, it turns out, are old friends. Hoop explains they “spent a lot of time living in a French-style house with a big oaktree in Tapanga Canyon.” Hoop is joined on stage for parts of her set by a second guitarist Johny Lexus and a backing singer Amy May. They’re playing their first gig together, Hoop tells us, before opening with a new song, “Whispering Light”. Tom Waits himself has described Hoop’s music as “like going swimming in a lake at night”; for my part, I think there’s something both theatrical and elemental to Hoop’s songs that remind me, fleetingly, of Kate Bush or Bjork. Her voice shifts into different registers, while the lyrics frequently mention skies, rivers, storms and winds’ or enchanted places where the boundaries shift and the dead might come back to life or animals talk. But, please, there’s nothing twee or precious here. She’s a great between-song raconteur, bantering about the collective nouns for birds with the audience, or how she lost her dress and car keys at Glastonbury, or opening “Intelligentactile 101” with “This is a children’s story. I heard it from my nephew. When my sister was pregnant. Except he turned out to be a girl. So I had some explaining to do.” We’re treated to five new songs, presumably destined for her forthcoming album Hunting My Dress (nothing to do with her Glastonbury experience, so claims), before returning to sing one final song, “Storms”, a cappella. Then it’s out into the night, and the fresh air. We'll be back for more Club UNCUT, at the Lexington on Pentonville Road, N1, on July 27. And that'll be Arbouretum's delayed show from March. Should be good. Before then, though, UNCUT will be covering Blur's Hyde Park show on Thursday this week.

In the new edition of the always interesting Yeti magazine, there’s a good and provocative piece about Jack Rose and the Black Twig Pickers, in which the author Justin Farrar calls out “All the shaggy indie hippies and underground freakers out there dabbling in Appalachian folk, country music and roots rock.” Rose, who Farrar honourably exempts from his rant, joins in, too. “We’re not dabbling with folk forms trying to make them contemporary or psychedelic,” he says. “We can actually play our instruments without the ‘free folk’ label, which I think lots of other musicians use to cover up their lack of musical skill. Plus, we swing like a motherfucker.” Well, speaking as an expert on “shaggy indie hippies and underground freakers”, and as a bit of a dabbler in “proper” American folk, I’m probably not altogether qualified to comment on the new “Jack Rose And The Blag Twig Pickers” album. But I can say unequivocally, Rose is right: they swing like motherfuckers. Rose you’ve probably come across before, as the doyen of the new school of American Primitive guitarists. The Black Twig Pickers are a pugnacious old-time collective from Richmond, Virginia, centred around a banjo player and fiddler called Mike Gangloff, who used to play with Rose in the wonderfully ominous freestyle explorers Pelt (I remember reviewing 2001’s “Ayahuasca” for The Wire, and being amazed and a bit out of my depth). “Jack Rose And The Blag Twig Pickers” actually revamps one “Ayahuasca” tune, “Bright Sunny South”, but the prevailing vibes here are very different. As Farrar describes in his Yeti piece, the group are fundamentally committed to making good-time old-time dance music. There’s none of the mysticism so often deployed by notionally ‘free folk’: essentially, Gangloff and Rose are intent on revisiting the Old Weird America, but not bothering too much about the weird bit. As far as I can see, that quest for ‘weirdness’, however self-conscious, is what often makes contemporary folk music achieve a sort of transcendence – though of course I suppose I’m approaching it from an indie-rock perspective, at heart. The pursuit of authenticity, or at the very least a kind of traditional orthodoxy, can sometimes, to my mind, end up as rather hokey; rough-hewn Appalachian kitsch, if you like. Parts of “Jack Rose And The Blag Twig Pickers” skirt a little close to that, not least when Gangloff lets rip with his parched holler. But the unshowy richness and vigour of their playing, and the evident joy which underpins it, make these 11 tracks transcendent in their own easy-going way. Much here is wonderful, from the unself-conscious flow of “Sail Away Ladies” into “I Shall Not Be Moved” onwards. By “Soft Steel Piston” they’re flying, Gangloff’s fervently sawed fiddle and Rose’s spirited picking sitting tight but comfortable over the locomotive clack of Nate Bowles’ washboard. “Kensington Blues”, an old Rose solo tune that resembled a sweet John Fahey piece in its original guise, is brilliantly fleshed out, its original concentrated solipsism socialised and transformed. And “Revolt” has a depth, intensity and virtuosity which borders on the cosmic, without ever betraying its resolutely earthy principles.

The biggest surprise of the day isn’t the weather, which is what you might call glorious, apart from a late afternoon cloudburst that at least gives me the excuse I’ve been looking for to hide under a table, perhaps the only sensible response to an appropriately thundery set by Ben Harper and the aptly-named Relentless7. No, what the day has unpredictably in store for us – the gosh-wow-did-that-really-fucking-happen-moment – lurks ahead, preening itself in anticipation of the many jaws it will cause in due course to drop. For the moment, though, let’s enjoy The Pretenders, who are on stage now, the streaming down on them and a crowd stunned by the heat, but quickly enlivened by a bracing romp through a couple of songs from the new Break Up The Concrete Album, a fierce “Boots Of Chinese Plastic” sounding as good as any of the acknowledged ‘classics’ from their back catalogue that quickly follow. By “Message Of Love”, three numbers in, Chrissie Hynde’s eyeliner is melting, pouring down one side of her face, which makes her look in close-up a bit like Alice Cooper on the inner sleeve of Love It To Death. She’s in great voice, though, and “Message Of Love” is the first of the crowd-pleasing hits that pepper their set, everyone one of them sounding timelessly brilliant. “Talk Of the Town” is quickly followed by another new song, “Love Is A Mystery”, Eric Haywood’s pedal steel, an unexpected voice in the instrumental mix, taking the lead here. The venerable “Back On The Chain Gang” gets a predictably big cheer, the crowd really getting into this now, the momentum continuing through the hard R&B blast of “Rosalee”, also from the recent album, guitarist James Walbourne taking a solo that’s so good Chrissie makes him play it again, which he does with even greater aplomb. A sultry “Brass In Pocket”, “I’ll Stand By You” and “Middle Of The Road” take things out on a knock-‘em dead high that makes me look forward to seeing them again soon at Latitude. Seasick Steve has become an inescapable festival favourite for reasons that genuinely elude me, but he proves here as he did at last year’s Latitude and elsewhere to be incredibly popular across a broad generational bandwidth, although it should be said that everyone here is of such a sunnily uncritical disposition they’d likely applaud a barking dog or a tap-dancing seal. I’m beginning to feel like a heretical grump in the company of so many people clearly cheered by the old bluesman and his grating down-home homilies, sub-Beefheartian boogie and practised humility, but then he plays something about a chicken and I am suddenly noticeable by my absence from the enthusiastic throng at the front of the stage. The storm that not much later sweeps Hyde Park has somewhat abated and the skies are slowly clearing when Fleet Foxes perfectly catch the brightening mood with “Sun Giant”, their opening song neatly coinciding with a parting of the previously ominous clouds and the tentative reappearance of the big yeller itself, one of those moments of synchronicity familiar to festival veterans, after which, as if the band themselves have been somehow miraculously responsible for the improving weather they can’t do much wrong. What follows is a largely ecstatic 50 minutes or so of thrilling harmonies, glorious melodies, and wonderful song. “White Winter Hymnal” and “”Ragged Wood” are predictably rhapsodic, but even better from where I’m standing are “Your Protector” and “Oliver James”, two of the less celebrated tracks from their much-feted debut, and a magnificent, soaring “Mykonos”. I’m on my way at a casual dawdle from the backstage area to the front of the stage when for a moment I’m convinced by a slow ominous rumbling that what I can hear is more of the thunder that had accompanied the earlier downpour, this time with the splintery crackle of not-too-distant lightning, something elemental anyway afoot that I can’t immediately put a name to that of course turns out to be Neil Young, plugging in and without attendant ado launching into a shuddering Neanderthal riff that mutates almost reluctantly into the belligerent intro to “Hey Hey My My (Into The Black)”, a song to which an added layer of poignant significance has been added by the inescapable events of the last few days, another pop king ending up on the autopsy table. What follows is one of the best shows I’ve ever seen Neil Young play, a full-on sonic rupture, two hours of unforgiving and unforgettable guitar distortion, seismic upheaval, deafening detonations, feedback rapture, wave after wave after crashing wave of noise, uplifting and triumphant, the kind of thing that tears vents in the atmosphere, disarranging the senses, wholly transcendent, an often savage aural maelstrom out of which emerges finally a charred beauty, that old ragged glory that is oft-mentioned in talk of Neil, his music and the way he plays it. We have in astonishing succession: “Mansion on The Hill”, a barn-burning honky-tonk rave-up on “Are You Ready For The Country?”, “Everybody Knows This Is Nowhere”, a fearsome “Spirit Road”, an astonishing version of “Words”, a crunching “Cinnamon Girl” and a thoroughly monstrous “Fuckin’ Up”. “Mother Earth” leads into what by now is a welcome acoustic set that includes a grave “The Needle And The Damage Done”, a winsome “Comes A Time”, “Unknown Legend”, a perhaps inevitable but entirely welcome “Heart Of Gold” and a version of “Old Man” that somewhat incongruously starts a mass singalong. Things turn sulphuric again in a hurry with a long and brooding “Down By The River” that seems destined never to end, but eventually does, and following the terse garage-boogie of “Get Behind The Wheel” from the recent Fork In The Road, a version of “Keep On Rockin’ In The Free World” that I am sure in some alternative universe or spooky other dimension continues even now to rage unstoppably. Tonight it reaches climax after teasing climax, ecstatic and deranged and after a while just exhilaratingly hilarious, Neil grinning madly as he comes back for one more chorus, and then another and another after that, no one by now wanting the thing to be put to bed, the delirium palpable. And he’s not done yet and tops even this with what’s become a formidable version of “A Day In The Life”, a song long-regarded by many as something no one in their right mind would think of playing live, including you might think Paul McCartney, who’s been standing at the side of the stage, but is within minutes at the microphone with Neil, arm around Neil’s shoulder, clearly euphoric, the crowd a-roaring. McCartney, now that things have moved on to a guitar-shredding instrumental section seems at a bit of a loss, not sure quite what to do, a problem he solves by waving his arms in the air, grinning wildly, dancing like someone who’s just been introduced to his feet and having a grand old time and then clawing at the strings of Neil’s guitar. It’s an amazing moment, and an amazing end to an amazing show.