Police officer very tough in this area (8)
I believe the answer is:
district
'this area' is the definition.
(I've seen this before)
'police officer very tough' is the wordplay.
'police officer' becomes 'di' (detective inspector).
'very tough' becomes 'strict' (strict can mean very tough or severe).
'di'+'strict'='DISTRICT'
'in' is the link.
(Other definitions for district that I've seen before include "Zone, area" , "Locality" , "Territory, zone" , "Area of a town or city" , "'Area, territory (8)'" .)