Former Conservative exploits justifications (7)
I believe the answer is:
excuses
'justifications' is the definition.
(excuse is a kind of justification)
'former conservative exploits' is the wordplay.
'former' becomes 'ex'.
'conservative' becomes 'c' (abbreviation commonly used in UK politics).
'exploits' becomes 'uses' (use is a kind of exploit**).
'ex'+'c'+'uses'='EXCUSES'
(Other definitions for excuses that I've seen before include "Gives reasons for" , "Defences of objective behaviour" , "reasons for failure" , "Lets (someone) off duty" , "Forgives" .)