It is so quiet in the big field by Latitude’s main stage that you can hear the flags that surround the arena fluttering in the breeze. This is Joanna Newsom’s first solo show in an age, she’s palpably, gigglingly nervous, and she’s playing a bunch of new songs. Pretty brave.

First, though, we get some of the highlights of the extraordinary Californian harpist’s first two albums: “The Book Of Right-On”, “Sadie”, an incredibly moving version of “Emily”. These are songs I’ve played more than virtually any others in the past few years, and yet they still stop me in my tracks, have a new resonance and impact every time. “Emily”, it’s worth noting, doesn’t miss the gorgeous orchestrations supplied by Van Dyke Parks on “Ys” – even the filigree coda is just as moving when she plucks it out on her harp.

This show, though, is of most interest – beyond the pleasure, of course, of seeing one of the world’s greatest singer-songwriters in harmoniously bucolic surroundings – for the unveiling of a clutch of new Joanna Newsom songs. The first, not strictly new, proves to be something of a red herring, being “Colleen” from last year’s “Joanna Newsom And The Ys Street Band” EP, and a feisty, playful Celtic twister, complete with ecstatic hiccups from the singer.

For the three new songs, however, retreats to a grand piano. It might be unwise to imagine that this is how they will eventually turn out on record; I seem to remember her playing “Ys” songs, long before they were recorded, in a similar way at a Queen Elizabeth Hall gig some years ago. But the most obvious shift is that these are slightly less tricksy, and with a pronounced soul rather than folk influence.

Two of them remind me a lot today of Laura Nyro, especially the magnificent gravity of “New York Tendaberry”. There’s one, especially, that could be called “Down In California”, with bluesy piano rolls, some passing mention of a fox that eats her goldfish, and a key line, “If I lose my head, where am I gonna leave it?”

The third, which for the purposes of this blog I’m going to call “Meet Me In The Garden Of Eden”, brings to mind one of the default comparisons for Newsom, Kate Bush, specifically “Army Dreamers”. I’m not convinced she’s ever written a catchier song.

Then it all goes enchantingly haywire. Some minutes into a ravishing “Sawdust And Diamonds”, there’s some clanking backstage which knocks her off her course and makes her nerves come to the fore. There soon ensues a sequence of giggles and embarrassed asides, as she keeps forgetting the labyrinthine lyrics and requires prompting by the audience.

“You really shouldn’t clap,” she says when she brings it to a premature end, mortified. Everyone in the massive crowd does anyway. Not least because a woman often stereotyped as some ethereal, supernatural creature has usefully proved herself human. But also because these songs and this performance have such strength, suppleness and emotional heft that they sustain their potency even as the singer seems to be disintegrating before our eyes. Look, I know I keep doing this, but I’m going soon, so I can say now with certainty: the best thing I’ve seen at Latitude.