Conservative person departing in chopper (7)
I believe the answer is:
cleaver
'chopper' is the definition.
(a cleaver chops things)
'conservative person departing' is the wordplay.
'conservative' becomes 'C' (UK political abbreviation).
'person departing' becomes 'leaver' (I've seen this before).
'c'+'leaver'='CLEAVER'
'in' acts as a link.
(Other definitions for cleaver that I've seen before include "A butcher's chopping tool" , "Meat axe" , "A clever sort of axe" , "(Meat) chopper" , "dangerous object?" .)