Slippery customer in a debatable election (3)

I believe the answer is:

eel

'slippery customer' is the definition.
(eel can mean a slippery person)

'in a debatable election' is the wordplay.
'in' indicates the answer is hidden within the clue.
'EEL' is hidden in the letters of 'debatable election'.

(Other definitions for eel that I've seen before include "Slippery type" , "Slippery person" , "Serpentine fish" , "Apode" , "Almost scaleless fish" .)

I've seen this clue in the Evening Standard.

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