Indian leader back in favour henceforth (5)
I believe the answer is:
nehru
'indian leader' is the definition.
(I've seen this before)
'back in favour henceforth' is the wordplay.
'back' says the letters should be written backwards.
'in' indicates a hidden word.
'urhen' is hidden in the letters of 'favour henceforth'.
'urhen' back-to-front is 'NEHRU'.
(Other definitions for nehru that I've seen before include "First Indian prime minister, 1947-64" , "First Indian PM" , "Student of Gandhi" , "Pandit . . . . ., former Indian Prime Minister" , "Former Indian leader" .)