Conservative in Sofia spinning debacle (6)
I believe the answer is:
fiasco
'debacle' is the definition.
(I know that debacle can be written as fiasco)
'conservative in sofia spinning' is the wordplay.
'conservative' becomes 'C' (UK political abbreviation).
'in' means one lot of letters goes inside another.
'spinning' indicates anagramming the letters.
'sofia' with letters rearranged gives 'fiaso'.
'c' put inside 'fiaso' is 'FIASCO'.
(Other definitions for fiasco that I've seen before include "Ridiculous and total failure" , "Ignominious result" , "Farcical disaster" , "An absolute mess, what a farce" , "Ignominious failure" .)