Artful Dodger, say, best Dickens character (10)
I believe the answer is:
pickpocket
'artful dodger say' is the definition.
(pickpocket from Dickens' Oliver Twist)
'best dickens character' is the wordplay.
'best' becomes 'pick' (I've seen this before).
'dickens character' becomes 'pocket' (Herbert Pocket, character in Great Expectations).
'pick'+'pocket'='PICKPOCKET'
(Other definitions for pickpocket that I've seen before include "Artful Dodger?" , "Tea leaf" , "Thief working in public places" , "Cutpurse" , "Dip" .)