Great blunder if one Conservative follows Socialist ultimately? (8)
I believe the answer is:
terrific
'great' is the definition.
(thesaurus)
'blunder if one conservative follows socialist ultimately?' is the wordplay.
'blunder' becomes 'err' (I've seen this before**).
'one' becomes 'i' (Roman numeral).
'conservative' becomes 'c' (abbreviation commonly used in UK politics).
'follows' means one lot of letters go next to another.
'ultimately?' suggests the final letters (I've seen 'ultimately' mean this).
The final letter of 'socialist' is 't'.
'err'+'if'+'i'+'c'='errific'
'errific' put after 't' is 'TERRIFIC'.
(Other definitions for terrific that I've seen before include "Excellent; causing fear" , "Excellent - awe-inspiring" , "Fit crier being excellent" , "frightening" , "Awesome" .)