Voting system in diocese creates wild activity (5)
I believe the answer is:
spree
'wild activity' is the definition.
'spree' can be an answer for 'activity' (spree is a kind of activity). I am unsure of the 'wild' bit.
'voting system in diocese' is the wordplay.
'voting system' becomes 'PR' (proportional representation).
'in' is an insertion indicator.
'diocese' becomes 'see' (both can mean a cathedral area).
'pr' going within 'see' is 'SPREE'.
'creates' is the link.
Can you help me to learn more?
(Other definitions for spree that I've seen before include "Session of over-indulgence" , "A lively extravagant outing" , "Unrestrained bout" , "Splurge" , "Carefree, lively outing" .)