Finish back in Widnes (3)
I believe the answer is:
end
'finish' is the definition.
(I know that finish is a kind of end)
'back in widnes' is the wordplay.
'back' shows that the letters should be reversed in order.
'in' indicates the answer is hidden within the clue.
'dne' is hidden within 'widnes'.
'dne' written backwards gives 'END'.
(Other definitions for end that I've seen before include "scrap" , "target" , "SECOND PART OF 24" , "Finished" , "Climax" .)