The Strawbs, “Part of the Union,” which pretty much takes the theme and some of the lyrics from Woody Guthrie’s “Union Maid.”
There is some dispute over whether it is a pro-labour or anti-labour song, but according to the BBC “Although the lyrics could be read as satirical of the trade union movement, the band has frequently stated that that’s not the case at all. In fact the song was picked up by the trade unions and became something of an unofficial anthem for them.”