Domains filling English politicians with anger (7)
I believe the answer is:
empires
'domains' is the definition.
(I know this)
'filling english politicians with anger' is the wordplay.
'filling' indicates putting letters inside.
'english' becomes 'E' (abbreviation).
'politicians' becomes 'MPs' (Members of Parliament).
'with' means one lot of letters go next to another.
'anger' becomes 'ire' (ire is intense rage).
'e'+'mps'='emps'
'emps' going around 'ire' is 'EMPIRES'.
(Other definitions for empires that I've seen before include "monarchies" , "more than one power base" , "Groups of states under one sovereign" , "Dominions" .)