Rubbish Conservative course on subterfuge (8)
I believe the answer is:
claptrap
'rubbish' is the definition.
(I've seen this before)
'conservative course on subterfuge' is the wordplay.
'conservative' becomes 'C' (UK political abbreviation).
'course' becomes 'lap'.
'on' means one lot of letters go next to another.
'subterfuge' becomes 'trap' (I've seen this in another clue).
'c'+'lap'+'trap'='CLAPTRAP'
(Other definitions for claptrap that I've seen before include "Balderdash" , "Pretentious talk or nonsense" , "Pretentious rot" , "Bull" , "poppycock" .)