Uncompromising MP is up for it on bit of coke, right? (9)
I believe the answer is:
hardliner
'uncompromising mp is up for it' is the definition.
I can't tell whether this defines the answer.
'bit of coke right?' is the wordplay.
'bit of' becomes 'hard' (I can't justify this - if you can you should give a lot more credence to this answer).
'coke' becomes 'line' (a line of cocaine).
'right?' becomes 'r' (abbreviation).
'hard'+'line'+'r'='HARDLINER'
'on' is the link.
Can you help me to learn more?
(Other definitions for hardliner that I've seen before include "Uncompromising person" , "Militant" , "Doctrinaire type" , "Uncompromising advocate" , "Inflexible ideologue" .)