Discloses secret: distressed staff beg, howl (5,3,4)

I believe the answer is:

blows the gaff

'discloses secret' is the definition.

'distressed staff beg howl' is the wordplay.
'distressed' indicates an anagram.
'staff'+'beg'+'howl'='staffbeghowl'
'staffbeghowl' is an anagram of 'BLOWS THE GAFF'.

(Other definitions for blows the gaff that I've seen before include "Blurts out secrets" , "Exposes a situation" .)

I've seen this clue in The Everyman puzzle in The Observer.

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