It’s a mark of how far Jonny Greenwood’s solo music has diverged from that of his parent band that literally no-one attending tonight’s EOTR headline slot on the Garden Stage will have come expecting to hear a note of Radiohead, or even much in the same soundworld, despite the gourmet (and, alas, utterly specious) rumour going round as the stage-time drew nearer that Thom Yorke was on Greenwood’s guestlist. Paradoxically, though, despite the aesthetic separation, it’s also a mark of how closely Greenwood’s name still clings to the Radiohead brand and consequent appeal that a gig like this occupies the Saturday-night headline slot of a major UK festival. After all, it’s very likely that the music Greenwood and his accomplices – a string quintet and a pianist – perform tonight is not just unfamiliar to 90% of his audience, but in other contexts would be actively alienating to them: alongside a selection of his soundtrack work for Paul Thomas Anderson movies, Greenwood also curates a selection of pieces from 20th-century classical music heavyweights that would be more at home in an acoustically pristine concert hall than a grassy field in Wiltshire.

Not that this is presented in some sort of didactic demonstration of sophistication, or some attempt to Give The Oiks Some Culture. Instead, it’s offered in the spirit of sharing, humility and intense shyness: before the performance begins, a projection beams up a message from Greenwood that reads, “They offered me a microphone, but I’m more happy typing… and playing”, and then throughout the set, messages in a similar tone appear that ask for patience while the musicians are tuning, and otherwise announce the names, composers and dates of each piece as they begin. The unspoken insistence here is that this is not posh music, or pretentious music, or even music that requires a university education to enjoy, but simply interesting, moving, heartfelt human expressions made into sound.

The programme begins and ends on his most romantic cues from There Will Be Blood and Phantom Thread, respectively, each of them unabashedly ardent Debussy pastiches that seem designed to ease the crowd into and out of the gig, but between those there are virtuoso piano demonstrations, the presentation of unusual instruments (including the ghostly ondes martenot that Greenwood has made a staple in recent Radiohead albums, and a gorgeously droning tanpura), and performances of pieces by Shostakovich, Berio, and Messaien that demonstrate beautifully fractured approaches to melody and harmony on top of almost hallucinatory timbres and textures that in the present context offer a welcoming link to Greenwood’s own music and almost will the attendant Radiohead Stans to go back to their boxsets of In Rainbows with new ears.

For one of the most accomplished guitarists of his generation, it’s perhaps a surprise to wait 50 minutes for the first guitar tone of the gig, but when it arrives it’s spellbinding. Greenwood wanders into the centre of the stage and performs Steve Reich’s Electric Counterpoint, a piece for solo guitar and backing track, alone and backlit into silhouette. In some hands, the piece can be ascetic and repetitive, but here is completely hypnotic and rather romantic. What’s more, as Greenwood’s fringe sways in front of his face and the guitar lines build around him, the show briefly morphs from subversive presentation of conservatoire music into full-on rock gig, with the hitherto mute crowd starting to whoop with every mutation of the music, and that pairing – of active, real-time, rock-show audience glee to really fairly esoteric music – is a pretty astonishing testament not just to Greenwood’s tenacity but also to End of the Road’s faith in their punters. Twenty minutes later, Greenwood offers a bashful wave to his crowd, and shuffles back down the ramp at the back of the stage. 

There are mutterings after the performance that this sort of thing would be lovely in The Barbican with a comfy seat and a £10 glass of red wine, but that End of the Road’s Saturday headline slot is neither the time nor the place for something this outre. That sort of misses the point though: by taking this music out of its rarefied concert hall environment and into a space where it’s perfectly acceptable for music fans to whoop mid-performance, and where there isn’t such a narrow etiquette involved in showing appreciation to or even just how and where to listen to the music, there’s a sense that Greenwood has bust open the doors to a world of music that a lot more people would enjoy, if only they felt they had permission, socially, culturally and intellectually.

Yes, there are issues surrounding the idea that the gatekeeper of this deeply complex and nuanced music is a millionaire rockstar, and that his cherry-picking approach to repertoire starts to resemble a sort of Jive Bunny megamix of post-war classical music that potentially bastardises the form. From another perspective, too, it’s also fairly conservative programming: the youngest non-Greenwood composition performed tonight is still twice as old as Kid A, meaning the last 40-odd years of the avant garde is pretty underrepresented here. In the moment, though, that oversight doesn’t feel like a pulled punch. If tonight shows anything, it’s that Greenwood deeply understands both his audience and the music they might be interested in, given half a chance, and also that he is in a unique position to expand his fans’ horizons and must accordingly use his powers for good.

As the crowd disperses after the show, a gaggle of young Radiohead Lads wander past me exclaiming to each other in surprised awe the brilliance of the music they just heard. If even a handful of Greenwood’s crowd tonight go home and discover something from this set that they end up falling in love with, you sense that his work here is done.

Photography by Rachel Juarez-Carr