Discover conservative attending church (5)
I believe the answer is:
catch
'discover' is the definition.
(as in catching someone in the act)
'conservative attending church' is the wordplay.
'conservative' becomes 'C' (UK political abbreviation).
'attending' becomes 'at' (e.g. at school means attending school).
'church' becomes 'ch' (abbreviation on maps etc).
'c'+'at'+'ch'='CATCH'
(Other definitions for catch that I've seen before include "Apprehend - drawback" , "Snag; be in time for (train)" , "Discover" , "problem being concealed" , "Hear < hit" .)