Left in charge, do a runner (4)
I believe the answer is:
flee
'do a runner' is the definition.
(I've seen this before)
'left in charge' is the wordplay.
'left' becomes 'l' (common abbreviation).
'in' indicates putting letters inside.
'charge' becomes 'fee' (fee is a kind of charge**).
'l' placed into 'fee' is 'FLEE'.
(Other definitions for flee that I've seen before include "rush" , "Turn tail" , "Maybe escape" , "Abscond" , "Run (from danger)" .)