One politician with extremely exceptional drive (5)
I believe the answer is:
impel
'drive' is the definition.
(I've seen this in another clue)
'one politician with extremely exceptional' is the wordplay.
'one' becomes 'I' (Roman numeral).
'politician' becomes 'MP' (Member of Parliament).
'with' is a charade indicator (letters next to each other).
'extremely' means to remove the middle letters (only the extremes of the word are used).
'exceptional' with its centre taken out is 'el'.
'i'+'mp'+'el'='IMPEL'
(Other definitions for impel that I've seen before include "Urge or force to action" , "Constrain" , "Force forwards" , "Force to act" , "Force into motion" .)