Big blow for English MP in quiz (7)
I believe the answer is:
tempest
'big blow' is the definition.
(I've seen this before)
'english mp in quiz' is the wordplay.
'english' becomes 'E' (abbreviation as in OED).
'in' is an insertion indicator.
'quiz' becomes 'test' (synonyms).
'e'+'mp'='emp'
'emp' going within 'test' is 'TEMPEST'.
'for' is the link.
(Other definitions for tempest that I've seen before include "Violent disturbance" , "terrible blow" , "Met pets in fierce storm" , "Play (with rough weather)" , "Violent windstorm" .)