Sanctimonious abstainer in politics once (4)
I believe the answer is:
pitt
'politics once' is the definition.
I can't judge whether this definition defines the answer.
'sanctimonious abstainer' is the wordplay.
'sanctimonious' becomes 'pi' (British abbreviation for pious).
'abstainer' becomes 'TT' (short for teetotaller, someone who avoids alcohol).
'pi'+'tt'='PITT'
'in' is the link.
Can you help me to learn more?
(Other definitions for pitt that I've seen before include "William - the Younger, twice PM" , "William --, early PM" , "One of two Tory prime ministers" , "Former Prime Minister" , "Brad --, US actor" .)