Saw voting system finished British (7)
I believe the answer is:
proverb
'saw' is the definition.
('proverb' can be a synonym of 'saw')
'voting system finished british' is the wordplay.
'voting system' becomes 'pr' (I've seen this in other clues).
'finished' becomes 'over' ('over' can be similar in meaning to 'finished').
'british' becomes 'b' (abbreviation e.g. in 'BBC').
'pr'+'over'+'b'='PROVERB'
(Other definitions for proverb that I've seen before include "Well-known statement incorporating general truth" , "'Adage, saw (7)'" , "Old saying, perhaps by Solomon?" , "Saying of great truth" , "Adage, pithy saying" .)