Storm caused by trial involving English politician (7)
I believe the answer is:
tempest
'storm' is the definition.
(I know that storm can be written as tempest)
'trial involving english politician' is the wordplay.
'trial' becomes 'test' (synonyms).
'involving' indicates putting letters inside.
'english' becomes 'E' (abbreviation).
'politician' becomes 'MP' (Member of Parliament).
'e'+'mp'='emp'
'test' enclosing 'emp' is 'TEMPEST'.
'caused by' is the link.
(Other definitions for tempest that I've seen before include "Violent Shakespearian storm" , "A turbulent storm of wind and rain" , "Play (with rough weather)" , "Shakespearean storm?" , "Violent disturbance" .)