People in authority have taken back prize money (3,5)
I believe the answer is:
top brass
'people in authority' is the definition.
(I've seen this before)
'taken back prize money' is the wordplay.
'taken back' shows that the letters should be reversed in order.
'prize' becomes 'pot' (as in a jackpot).
'money' becomes 'brass' (informal term for money).
'pot' back-to-front is 'top'.
'top'+'brass'='TOP-BRASS'
'have' acts as a link.
(Other definitions for top brass that I've seen before include "Most important leaders, officers, etc" , "High-ranking figures of authority" , "management" , "senior command" , "Senior military personnel" .)