Leader of Opposition helping to produce speech (7)
I believe the answer is:
oration
'speech' is the definition.
(oration is a kind of speech)
'leader of opposition helping' is the wordplay.
'leader of' suggests taking the first letters.
'helping' becomes 'ration' (a ration is a serving or helping).
The initial letter of 'opposition' is 'o'.
'o'+'ration'='ORATION'
'to produce' is the link.
(Other definitions for oration that I've seen before include "A formal or ceremonial speech" , "lecture" , "words" , "A formal or public speech" , "Platform speech" .)