GallanTed just used a phrase which has always made me wonder. He said "I'm not a grass" which reminded me of watching The Bill (a fave of mine) where there's at least 3 instances in every episode of someone with a cockney accent saying "I won't grass 'im up - e's me mate" or similar.

I get the context, but where does the term come from? Etymology please kids...

Hev