Trying to find a film. via /r/movies

It’s a film set in the west indies in maybe the 60s or 70s. Story follows two gangs. Most memorable character was a youngish guy name of ‘ratty’ Always wearing red shorts no top. Lots of weed football and gang conflict. I saw it on late night TV by chance but never caught the name. Any help finding it would be greatly appreciated! Figured this would be a good place to start!