Skinner, a past policeman (6)

I believe the answer is:

peeler

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'policeman' is the definition.
(I have seen 'Old policeman' mean 'peeler' so perhaps 'policeman' could also mean 'peeler')

I don't understand the remainder of the clue.

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(Other definitions for peeler that I've seen before include "Old London policeman" , "apprehended by a _____?" , "Old copper" , "Kitchen knife" , "Potato skinner" .)

I've seen this clue in the Evening Standard.

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