His experience at the Scottish Mining Museum in Newtongrange was the start for an extended love affair with brass band music, which has led to the creation of a major new cultural project bringing the worlds of music and theatre together.
Green’s growing interest in brass band competitions and the former mining communities that are modern-day musical strongholds took him across the UK and to the national championships in the Royal Albert Hall.
And it led to the creation of a new drama set in a fictional post-mining town in Scotland, which has seen Lau collaborate with the Whitburn Band, Scotland’s current brass band champions, and the Royal Lyceum Theatre in Edinburgh.
Anna Russell-Martin will play the lead role of troubled teenager Keli in the premiere of a live stage version on Sunday of “Keli”, which will launch as an audio drama later this month.
Created by Green and theatremaker Wils Wilson, associate director at the Lyceum, over the last 18 months, the show will also feature River City, Crime and Outlander star Tam Dean Burn, as well as members of the West Lothian band.
Green, who moved to Edinburgh from Norwich in the mid-1990s, is best known as the accordion player in multi award-winning trad trio Lau.
He said: ‘I just had no idea how many brass bands there were in Scotland or how good they were until I went to that 'brass in the park' event.
"I just loved the sound of them, but was also fascinated by the fact I didn’t really know anything about this world. It all seemed to be a bit hidden, even though it is right here.
“I’ve spent a bit of time with brass bands now and it is quite an insular community. They end up playing to themselves quite a lot."
Green began working with brass bands on his musical projects and created a documentary series for the BBC on the UK-wide scene.
But it was The Servant, a 1923 fairytale by Austrian writer Hermynia Zur Mühlen that provided part of the inspiration for Keli, which sees the young musician encounter a 150-year-old miner.
Green added: “It was all about the dangers of private ownership, about a village that essentially sells everything it owns and shafts itself.
"I felt there was something interesting in there about the miners’ strike, trade unionism and brass bands.
"My first instinct was to try to make a period piece resetting that fairytale in a 1980s mining town, but I felt that so much great work set during the strikes had already been done.
"One of the really interesting things about brass bands these days is there are lots of young players.
"So our story is about a young woman in her late-teens in a fictional post-mining town in central Scotland.
"What is left in that community is an ethos, an attitude and the band, which is a huge part of the lives of people.
“Keli has always been a very good tenor horn player. It’s the only thing in her life that really makes sense. She has left school and feels quite crushed. The band room is a safe, secure and regimented environment for her and she is easily the best player in the band."
Keli is being staged at the Lyceum at 5pm on Sunday, when it will also be live-streamed from the venue, and will be launched as an audio drama on the theatre’s Sound Stage platform on 26 April.