Agreement from politician blocking company law (7)
I believe the answer is:
compact
'agreement' is the definition.
(compact is a kind of agreement)
'politician blocking company law' is the wordplay.
'politician' becomes 'mp'.
'blocking' is an insertion indicator.
'company' becomes 'co' (abbreviation).
'law' becomes 'act' (I've seen this before**).
'co'+'act'='coact'
'mp' put within 'coact' is 'COMPACT'.
'from' is the link.
(Other definitions for compact that I've seen before include "Mutual agreement" , "Dense; treaty" , "'Condensed, portable (7)'" , "Dense; agreement" , "bargain" .)