Voting system is working in gaol (6)
I believe the answer is:
prison
'gaol' is the definition.
(thesaurus)
'voting system is working' is the wordplay.
'voting system' becomes 'pr' (I've seen this in other clues).
'working' becomes 'on'.
'pr'+'is'+'on'='PRISON'
'in' is the link.
(Other definitions for prison that I've seen before include "Place of confinement" , "Place of detention for criminals" , "porridge" , "Jail" , "Gaol" .)