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 cannot judge whether this works.
'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' indicates putting letters inside.
The first letter of 'trotskyist' is 't'.
'that'+'cherie'='thatcherie'
't' going inside '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" .)