Corrupt MP gains camera for dirty politics (5,8)
I believe the answer is:
smear campaign
'dirty politics' is the definition.
(I've seen this in another clue)
'corrupt mp gains camera' is the wordplay.
'corrupt' indicates an anagram.
'mp'+'gains'+'camera'='mpgainscamera'
'mpgainscamera' with letters rearranged gives 'SMEAR CAMPAIGN'.
'for' is the link.
(Other definitions for smear campaign that I've seen before include "Organised vilification" , "Concerted operation to sully someone's name" , "attempt to bring discredit" , "Manager is camp (anag)" , "Organised attempt at defamation" .)