Lyric discussion by cscheybeler 

Cover art for Sloth lyrics by Fairport Convention

Some of Richard Thompson's lyrics can be obscure (eg Now Be Thankful) but I always assumed this was about war, maybe Napoleonic. "Call to your colours, friend" could be military, as in trooping the colour?

As for the title, sloth could refer to the slow tempo.

Song Meaning

@cscheybeler It's most definitely about war, and about how it perverts the state of things so that the "right thing's the wrong thing." Things like killing and bombing that should always be considered wrong to do are considered "right" during wartime.