Drive for the police (5)
I believe the answer is:
force
I believe this clue is a double definition.
'drive' is the first definition.
(synonyms)
'police' is the second definition.
(the force can refer to the police force)
'for the' acts as a link.
(Other definitions for force that I've seen before include "Coercion; influence" , "Compulsion - police" , "fall" , "Power; army" , "Powerful effect or influence" .)