If folk is the music of the people, then why isn’t there more theatre of the people to go with it? With its merciless chronicle of human devastation, the first world war offers a rich harvest for such productions – and a glaring temptation to strangle it in overwrought sentiment and cliche.

Sam Sweeney – fiddle player and the youngest member of Bellowhead – avoids such pitfalls in a wondrously fresh and slightly quirky take on an old theme, staging a story that almost literally fell into his lap. Buying an apparently brand-new violin in Oxford as an 18-year-old student in 2007, Sweeney got it home to discover an inscription indicating the instrument was “Made in the Great War” by Richard S Howard in Leeds in 1916.

His subsequent quest to discover the history of the violin – and its maker – drives a show which, in the hands of narrator Hugh Lupton (who has previously collaborated so fruitfully with singer Chris Wood) is charming, enlightening, warm and ultimately shocking. With Lupton charting Richard Howard’s journey from husband, father, music-hall performer and luthier to its horrific denouement on the front line in Flanders, Sweeney – all braces and shorn hair – plays the fiddle at the heart of the tale alongside concertina wizard Rob Harbron and fellow Bellowheader Paul Sartin, who recreates the clipped enunciation of wartime singers with startling accuracy.

Between them, they weave a rich variety of moods around Lupton’s impossibly engaging storytelling and effective screened images – marches, traditional tunes, music hall songs, Paganini et al, climaxed by Sweeney’s epic The Ballad of Richard Howard, which cleverly reinterprets the classic ballad The Cruel Sister. There’s a touch of Michael Morpurgo about it all, with clear potential for expansion via additional music and drama; but for now organic intimacy is key to an unusually potent show.

• At Key, Peterborough, tonight. Box office: 01733 207239. Then touring.