Vague but PLEASE HELP!!!

[Qmark78]

Around maybe 15 years ago there was a one off drama on BBC1 it was about a bunch of school kids who decide to be a Police force it had the bloke that played Alan Rockcliffe in it and he turns out to be a Pervert so this Kids Police force kill him

it was very dark but excellent i cant remember the name of it or ever known of it being repeated

does anybody know it it or remember it??

[Qmark78]

Didnt have Rockcliffe in it somebody who looked like him then!! but i found it

http://www.imdb.com/title/tt0296151/