Conservative church stopping fool's entry (6)
I believe the answer is:
access
'entry' is the definition.
(I've seen this before)
'conservative church stopping fool's' is the wordplay.
'conservative' becomes 'C' (UK political abbreviation).
'church' becomes 'CE' (abbreviation for Church of England).
'stopping' means one lot of letters goes inside another (stopping can mean blocking a gap).
'fool's' becomes 'ass' (ass is a kind of fool).
'c'+'ce'='cce'
'cce' put into 'ass' is 'ACCESS'.
(Other definitions for access that I've seen before include "OK to go in" , "drive, perhaps" , "A way of approaching" , "Point of entry" , "Way of entering or leaving" .)