Moaning when the workers' leader is causing trouble (7)

I believe the answer is:

wailing

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'moaning' is the definition.
(thesaurus)

'the workers' leader is causing trouble' is the wordplay.
'leader' says to take the initial letters.
'is causing trouble' becomes 'ailing' (I can't justify this - if you can you should believe this answer much more).
The initial letter of 'workers' is 'w'.
'w'+'ailing'='WAILING'

'when' acts as a link.

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(Other definitions for wailing that I've seen before include "Jerusalem site sacred to Jews for prayer and lamentation" , "Greeting" .)

I've seen this clue in the Evening Standard.

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