Jonny Greenwood on BBC Radio 3

Jonny Greenwood talks Radio 3's Here and Now through the concert he curated for the Ether festival at London's Royal Festival Hall, with the London Sinfonietta, the Nazareth Orchestra and, at the end, Thom Yorke. He opened with Ligeti's Ramifications, for two string groups tuned a quarter-tone apart, because its microtones stay beautiful instead of being used for effect. Messiaen's Fête des belles eaux is for six ondes Martenot, the early electronic instrument he plays himself. “I'm quite evangelical about it actually,” he says; it took him years to find a photograph of one.

His own Piano for Children began as a predictable piece that a child played and he transcribed, mistakes, hesitations and hammered chords included, so the pianist John Constable had to learn to play badly. “It's meant to be a conflict between him playing wrong and the string players trying to make sense of him.” He wrote Smear, for two ondes and ensemble, on tour in Amsterdam, and found its structure only when he bought paper, glue and Tipp-Ex and cut it up by hand, which is when he understood why computers have cut and paste. Umm Kulthum's “Enta Omri” is on the bill out of his fascination with her, and the Nazareth Orchestra, who specialise in her music, agreed to come. Penderecki's Capriccio is there too; people tell him Penderecki is out of fashion, a bit 60s, but it still sounds to Jonny like nothing else.

The night ended with Yorke singing two Radiohead songs. “Arpeggi” is new, built from cycling arpeggios in threes, fours and fives, and Jonny isn't sure how a rock singer who can count to four kept up with it. Yorke wrote the wordless “Where Bluebirds Fly” on a sequencer the size of a lunchbox. Jonny feared it would be pastiche with the Nazareth Orchestra, who told him it was in one of their modes and it fell under their fingers. The star of the show for him was their tambourine player, getting hundreds of rhythms out of the simplest instrument on stage.