Senior politician (7)
'senior politician' is the definition.
(eg cabinet minister)
This is all the clue.
(Other definitions for minister that I've seen before include "Member of the clergy or of the Front Bench" , "Servant of state or church" , "One of the clergy" , "Senior politician" , "Cabinet member" .)
(Other definitions for grandee that I've seen before include "European lord" , "Angered over Spanish noble" , "Enraged (anag) - Spanish nobleman" , "Person of eminence" , "A Spanish or Portuguese noble" .)