Lionel Bart musical (6)
I believe the answer is:
oliver
'lionel bart musical' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for oliver that I've seen before include "Orphan recruited by criminal gang" , "Dickens boy named Twist" , "Character in Dickens" , "First name of Dickens boy Twist" , "-- Reed, actor" .)