English politician with passion for supreme dominion (6)
I believe the answer is:
empire
'supreme dominion' is the definition.
'english politician with passion' is the wordplay.
'english' becomes 'e' (abbreviation).
'politician' becomes 'mp' (Member of Parliament).
'with' means one lot of letters go next to another.
'passion' becomes 'ire' (I've seen this before).
'e'+'mp'+'ire'='EMPIRE'
'for' acts as a link.
(Other definitions for empire that I've seen before include "Group of states under the control one authority" , "Former British-ruled countries" , "Widespread political or industrial organisation" , "Group of states with a single monarch" , "See 5" .)