Right-winger, originally Trotskyist, that Blair, perhaps, welcomes (11)
I believe the answer is:
thatcherite
'right-winger' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'originally trotskyist that blair perhaps welcomes' is the wordplay.
'originally' says to take the initial letters.
'blair perhaps' becomes 'Cherie' (Cherie Blair, wife of Tony Blair).
'welcomes' means one lot of letters goes inside another.
The initial letter of 'trotskyist' is 't'.
'that'+'cherie'='thatcherie'
't' put within 'thatcherie' is 'THATCHERITE'.
Can you help me to learn more?
(Other definitions for thatcherite that I've seen before include "One supporting former PM's policies" , "Old Maggie fan" , "Type of Conservative" , "Conservative politician" , "old political supporter" .)