Finish back in Widnes (3)
I believe the answer is:
end
'finish' is the definition.
(come to an end)
'back in widnes' is the wordplay.
'back' says the letters should be written in reverse.
'in' says the answer is hidden in the clue.
'dne' is hidden within 'widnes'.
'dne' in reverse letter order is 'END'.
(Other definitions for end that I've seen before include "scrap" , "target" , "SECOND PART OF 24" , "Finished" , "Climax" .)