For one of the band's performances on Top of the Pops they wore Union-style uniforms, as can be seen on YouTube and on 45 single record cover.
The song goes on to describe how Billy is killed in action in a pitched battle after volunteering to ride out and seek reinforcements.
In the end, the heartbroken woman throws away the official letter notifying her of Billy's "heroic" death.
The Bo Donaldson and the Heywoods version was a massive hit in Latin America and Japan as well, but it remained largely unknown elsewhere.
Massive Attack's 1991 track Blue Lines (from the album of the same name) features the lyrics "Take a walk, Billy, don't be a hero".