Policeman in area apprehending Prince (9)
I believe the answer is:
inspector
'policeman' is the definition.
(inspector is a kind of policeman)
'in area apprehending prince' is the wordplay.
'area' becomes 'sector' (sector is a kind of area**).
'apprehending' is an insertion indicator.
'prince' becomes 'p'.
'sector' placed around 'p' is 'spector'.
'in'+'spector'='INSPECTOR'
(Other definitions for inspector that I've seen before include "reviewer" , "senior cop" , "controller" , "one to check" , "bluebottle!" .)