Narration, true, about Conservative, just what’s needed (7)
I believe the answer is:
recital
'narration' is the definition.
(I know that narration can be written as recital)
'true about conservative just what's needed' is the wordplay.
'true' becomes 'real' (similar in meaning).
'about' means one lot of letters goes inside another.
'conservative' becomes 'C' (UK political abbreviation).
'just what's needed' becomes 'it' (as in 'that's it!').
'c'+'it'='cit'
'real' placed around 'cit' is 'RECITAL'.
(Other definitions for recital that I've seen before include "(Usually solo) concert" , "Narrative" , "Telling" , "Narration" , "Article found in performance" .)