In our now time-honoured Sunday tradition, we turn to music. This week in my new series Hymns from the Radio Dial, we get political with a call for social justice from Psalm 137. It is most likely that we all remember Rivers of Babylon as a late-70s song by German disco group Boney M. In fact, the song was written and recorded in 1972 by Brent Dowe and Trevor McNaughton of The Melodians (1965-73), a Jamaican group in Kingston, the birthplace of reggae.