SOLVED! Kid joins gang of midgets/dwarves troll like creatures [s]

[Liam]

I borrowed this book in 1985 from a library in rural Ireland. It was either a children's or YA book that revolved around warring gangs of some kind of short creatures, I think they were troll like. They also battled police and attacked their kneecaps with slingshots or stones. The protagonist is a child who discovers one of the gangs and joins them.

I'd guess it was written 70's or early 80's.

(view spoiler)[there is some level of pathos involved as one of the gang leaders dies near the end (hide spoiler)]

[Sue]

The Borrible trilogy by Michael de Larrabeiti?

[Liam]

Ha! Brilliant Sue, you got it in one. Google had me defeated!