Charley,

I think you have a point.
In the UK 'scum' is an epithet usually reserved for someone who commits an act of unspeakable depravity - child murder, violence against the elderly etc.
It has, as far as I know, no 'gentle' connotations here.
Cheers, Charlie, that is exactly the kind of information I was looking for.
I note that the song in question also appears in another Mudcat thread about anti-smoking songs. I didn't get the impression it was posted here with any mischievous intent.