One's told sad story after all banks withdraw safety feature (8)
I believe the answer is:
isolator
'one's told sad story after all banks withdraw' is the definition.
I can't judge whether this defines the answer.
'safety feature' is the wordplay.
'safety' becomes 'isola' (I can't explain this - if you can you should believe this answer much more).
'feature' becomes 'tor' (I have seen 'feature of Glastonbury' mean 'tor' so perhaps 'feature' could also mean 'tor').
'isola'+'tor'='ISOLATOR'
Can you help me to learn more?
(Other definitions for isolator that I've seen before include "Switch cutting off part of circuit" , "The curse of Crusoe" , "(Electrical) switch" , "Switch cutting off electricity" , "Switch cutting off power" .)