Journalist's flipping rubbish on Edward I (6)
I believe the answer is:
editor
'journalist's' is the definition.
(senior journalist)
'flipping rubbish on edward i' is the wordplay.
'flipping' says the letters should be written backwards.
'rubbish' becomes 'rot' (both can mean nonsense).
'on' means one lot of letters go next to another.
'edward' becomes 'Ed' (short for Edward).
'rot' back-to-front is 'tor'.
'ed'+'i'='edi'
'tor' after 'edi' is 'EDITOR'.
(Other definitions for editor that I've seen before include "Director of 3 down" , "Rag worker" , "Person who determines the final content of a text" , "Senior hack" , "Person in charge of paper" .)