Group welcoming Conservative, heretical bigot (9)
I believe the answer is:
sectarian
'bigot' is the definition.
(I know that sectarian is a type of bigot)
'group welcoming conservative heretical' is the wordplay.
'group' becomes 'set' (both can mean a collection).
'welcoming' is an insertion indicator (in sense of 'inviting in').
'conservative' becomes 'C' (UK political abbreviation).
'heretical' becomes 'arian' (I've seen this in other clues).
'set' placed around 'c' is 'sect'.
'sect'+'arian'='SECTARIAN'
(Other definitions for sectarian that I've seen before include "Adhering to a faction or doctrine" , "Ascertain to be with religious prejudice" , "Prejudiced against other religions? So ascertain" , "from an unorthodox group" , "Of a religious faction" .)