Dystopian tale of British boy and drug trafficker (5,6)
I believe the answer is:
blade runner
'dystopian tale' is the definition.
(I know that Blade Runner is a dystopian tale)
'british boy and drug trafficker' is the wordplay.
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'boy' becomes 'lad' (informal term for boy).
'and' means one lot of letters go next to another.
'drug' becomes 'e' (E is another name for ecstasy).
'trafficker' becomes 'runner' (as in someone running drugs).
'b'+'lad'+'e'+'runner'='BLADE RUNNER'
'of' is the link.
(Other definitions for blade runner that I've seen before include "1982 sci-fi film" , "Nineteen eighty two sci-fi film based on a Philip K. Dick story" .)