Must rewrite internal broadcast (5)
I believe the answer is:
strew
'broadcast' is the definition.
(I've seen this in another clue)
'must rewrite internal' is the wordplay.
'internal' indicates the answer is hidden within the clue.
'STREW' is hidden within 'must rewrite'.
(Other definitions for strew that I've seen before include "Scatter untidily" , "Sprinkle" , "Scatter loosely" , "Scatter, spread around" .)