‘I gather it was heard by about a million people … I received thousands and thousands of letters’. So wrote cellist Beatrice Harrison following her iconic duet with the nightingale, broadcast by 2LO, the London station of what was then the British Broadcasting Company, on May 19, 1924.

What was it that made her cello and nightingale duetting so popular that the spring broadcasts were rescheduled for the next 12 consecutive years by the BBC?

Was it the playing of Harrison herself? Already world famous for her interpretation and recording of Elgar’s Cello Concerto, 1924 saw Harrison delight London’s box offices: in the three months running up to the nightingale broadcast she gave premieres of sonatas by Bax, Ireland and Delius, as well as the first British performance of Kodály’s unaccompanied sonata. Her musicianship was described by The Times as ‘intensely enjoyable because of the presence of this undefinable quality in her playing, a peculiar clarity of line and phrasing which can only be called eloquence’.

Or was it the sound of the nightingale? (And by the way, the rumour that Harrison’s nightingale was in fact a whistler, or siffleur, receives its just rebuttal in a documentary to be broadcast on the centenary, May 19, 2024, at 7.15pm on BBC Radio 3!). Since time immemorial the nightingale (from the Old English nihtegale, or ‘night songstress’, though we now know it’s only the male bird that sings) has inspired poets, authors and composers to celebrate its song. From Homer and Ovid to Keats and Shelley, the nightingale – often cast as Philomela, its mythological embodiment – is proclaimed the most powerful of communicators, be it of springtime or mourning or love.

Adrian Bradbury and Andrew West record ‘The Pre-Raphaelite Cello’

Of course, wireless listeners all over the British Empire were tuning in to be transported by both the sound of the cello and the sound of the birdsong. But what took the broadcast onto another plain was the interaction between those two voices. Harrison describes the scene: ‘As the nights began to feel warmer I had a sudden longing to go out into the garden and play my cello and gaze upon the beauty of it all as the moon peeped out through the trees. I sat on an old seat which surrounded an ivy-clad tree. I began to play, very lazily, all the melodies I loved best and to improvise on them. I began the Chant hindou by Rimsky-Korsakov and after playing for some time I stopped. Suddenly a glorious note echoed the notes of the cello. I then rolled up and down the instrument, up to the top and down again: the voice of the bird followed me in thirds!… I think he liked Chant hindou best for he blended with it so perfectly. I shall never forget his voice that night, or his trills, or the way he followed the cello so blissfully.’

Without interaction, whether it be instrument to instrument, voice to voice, instrument to orchestra, dancer to orchestra etc, music is stillborn. In 1924 this was taken for granted but I fear 100 years later there is a real danger that the magic of interaction is disappearing from our ‘musical’ world. Karaoke (‘empty orchestra pit’ in Japanese) has become commonplace in the worlds of ballet and dance, with non-interactive recorded music replacing live musicians. AI is tricking our ears with ever more realistic samples; whereas a decade ago sample programmes struggled to mimic the transitions between an individual player’s notes, they are now beginning to ape the complex musical dialogue between players. Harrison would not have recognised this solitary world, and surely the best way to celebrate the centenary of her nightingale broadcast is to continue to fight for what it is to be a musician rather than a machine – real players listening and reacting to one another in the presence of a live audience. Whether it’s a brother and sister playing to their mum in the front room or one million people tuning in to hear a cello and a nightingale, that, and only that, is music.

‘The Pre-Raphaelite Cello’ (Adrian Bradbury, cello and Andrew West, piano), an album of music associated with Beatrice Harrison by Percy Grainger, Roger Quilter and Cyril Scott, is released by SOMM Recordings on May 17: listn.fm/preraphaelitecello

‘The Cello and the Nightingales’, a new edition of Beatrice Harrison’s autobiography edited by Patricia Cleveland-Peck, is published by Canongate on May 9: canongate.co.uk