Say Mr Powell brings one back to church (5)
I believe the answer is:
enoch
'say mr powell' is the definition.
The definition suggests a singular noun which matches the answer.
'one back to church' is the wordplay.
'back' is a reversal indicator.
'to church' becomes 'ch' (common abbreviation).
'one' back-to-front is 'eno'.
'eno'+'ch'='ENOCH'
'brings' acts as a link.
Can you help me to learn more?
(Other definitions for enoch that I've seen before include "Biblical character" , "Man in Bible" , "Cain's eldest son - Methuselah's father" , "-- Powell, former politician" , "Oldest city father" .)