Leader of Opposition helping speech (7)
I believe the answer is:
oration
'speech' is the definition.
(I know that oration is a type of oratory)
'leader of opposition helping' is the wordplay.
'leader of' indicates taking the first letters.
'helping' becomes 'ration' (a ration is a serving or helping).
The initial letter of 'opposition' is 'o'.
'o'+'ration'='ORATION'
(Other definitions for oration that I've seen before include "An eloquent speech" , "A formal or public speech" , "A public or ceremonial speech" , "A long ceremonial speech" , "lecture" .)