Insisted on (8)
I believe the answer is:
demanded
'insisted on' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for demanded that I've seen before include "Insisted upon" , "Requested peremptorily - won't take no for an answer" , "Called for" , "Requested imperiously as if by right" , "Requested forcefully" .)