Defence of very popular article, in a manner of speaking (11)
I believe the answer is:
vindication
'defence' is the definition.
('vindication' can be a synonym of 'defence')
'very popular article in a manner of speaking' is the wordplay.
'very' becomes 'v' (abbreviation).
'popular' becomes 'in'.
'article' becomes 'a' (indefinite article).
'in' means one lot of letters goes inside another.
'a manner of speaking' becomes 'diction' (I've seen this before).
'a' inserted inside 'diction' is 'dication'.
'v'+'in'+'dication'='VINDICATION'
'of' is the link.
(Other definitions for vindication that I've seen before include "acquittal" , "successful defence" , "Defence - into da Vinci (anag)" , "clearance" , "Evidence that frees from blame, criticism etc" .)