Doubt, hell! Former prime minister ultimately moved ahead (8)
I believe the answer is:
distrust
'doubt' is the definition.
(I know that distrust is a type of doubt)
'hell former prime minister ultimately moved ahead' is the wordplay.
I cannot really see how this works, but
'hell' could be 'dis' (term for the underworld in Greek myth) and 'dis' is found within the answer.
The remaining letters 'trust' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for distrust that I've seen before include "Regard (person) with suspicion" , "Stir dust up and be suspicious" , "Lack confidence in honesty or ability" , "Stir dust (anag.)" , "Durst sit with lack of confidence?" .)