If you’ve seen the movie ‘Walk The Line’ (which seemed to be on again sometime over the festive season) you’ll know well something of the atmosphere at Johnny Cash’s 1968 Folsom Prison show. There is an almighty noise throbbing through  the refectory walls as Cash and his band wait to come on stage and an ominous sense of fear while they listen to the sound of the inmates stamping their feet on the floor. It’s perhaps that tension, so beautifully caught in James Mangold’s film, which is the necessary fuel for the performance.

Live at Folsom was a high risk strategy at the time. Johnny Cash’s own personal story may have had a few flashpoints during the sixties but the general trajectory of his career was heading downwards. It had been a while since he’d had a hit record and, although adored by the country community and those in the wider music world who really understood, he was already becoming a name from the past. Looking at what had happened in 60’s – when pop music was really properly invented – it’s not difficult to see the speed of change. Stand still for a moment and the music business would quickly leave you behind.

Into all of that Johnny Cash threw a line back to the start of his career. Based on the love of one song, Folsom Prison Blues, Cash had built a dedicated audience behind the bars of America’s penitentiaries. Folsom Prison Blues had been a single from his first album in 1955 and the song became a trademark opener in all his live appearances. As early as 1958 Cash’s popularity within the penal system took him to play at San Quentin, one of California’s biggest jails. On New Year’s Day 1958 (60 years ago this month) a ‘captive’ audience that day included Merle Haggard, serving time for robbery and starting to plot his own career in country music.

Ten years later Johnny Cash, with the original musicians from his Sun Records session of 1955, would perform two concerts at Folsom Prison in California which would be recorded by Columbia Records by the legendary Bob Johnstone (Dylan, Leonard Cohen and Simon and Garfunkel) for a live album release. The gamble paid of. ‘At Folsom Prison’ launched the second-half of Johnny Cash’s career. Indeed, were it not for that album it’s unlikely we’d still be celebrating him as one of the country greats he undoubtedly is. Critically lauded, it went on to be a massive selling record around the world and as recently as 2003 was made no 88 in Rolling Stone’s top 500 albums of all time.

This Tuesday we’ll play cuts from the album and talk about that special relationship between Johnny Cash and the men who listened to his music who could only dream of travelling. As old as country music itself the relationship between the prisoner and the song is long and intertwined. Most of the men listening to Johnny and The Tennessee Three that day in Folsom would know this lyric by Hank Williams, and dream of places they’d never see:

All alone I bear the shame
I’m a number not a name
I heard that lonesome whistle blow
All I do is sit and cry
When the ev’nin’ train goes by
I heard that lonesome whistle blow

On the second song on the album, the great Merle Travis’s ‘Dark As A Dugeon,’ a nervous sounding Johnny breaks out of his performance to explain to the Folsom inmates that they are recording the gig for a future release. There is a mutual understanding in that song, shared by the performer and the audience on the day, that for many, there is no escape or even possibility of redemption. In the jail, life was indeed as dark as a dungeon. Join us as we hear how Johnny Cash opened a window into that reality and, in his own solidarity with those inside the bars allowed us to imagine and them to dream of a better day ahead.

We’re live on BBC Radio Scotland this Tuesday evening from five past nine.