Demolish large new English comprehensive (7)
I believe the answer is:
Here is my best explanation:
'comprehensive' is the definition.
('general' can be similar in meaning to 'comprehensive')
'demolish large new english' is the subsidiary indication.
'demolish' indicates an anagram.
'new' becomes 'n'.
'english' becomes 'e' (abbreviation).
'largene' is an anagram of 'general'.
(Other definitions for general that I've seen before include "Non-specialist - army officer", "Not specialised, rank", "Army officer", "Rank; normal, usual", "Enlarge for senior army officer", "Common - army officer", "Military commander", "Of wide application", "Not specialised, like army chief" and "The senior officer is common and widespread".)