English party talk is complicated (9)
I believe the answer is:
elaborate
'is complicated' is the definition.
(I've seen this before)
'english party talk' is the wordplay.
'english' becomes 'E' (abbreviation).
'party' becomes 'lab' (abbreviation for Labour).
'talk' becomes 'orate' (to orate is to give a speech).
'e'+'lab'+'orate'='ELABORATE'
(Other definitions for elaborate that I've seen before include "Polish" , "Complicated or ornate" , "involved" , "Develop in more detail" , "Explain details" .)