Politician and political staff held up in hole, leaving (10)

I believe the answer is:

decampment

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'leaving' is the definition.
(I know that decampment is a type of abandonment)

'politician and political staff held up in hole' is the wordplay.
I cannot really see how this works, but
'politician' could be 'pm' (short for prime minister) and 'pm' is found within the answer.
'and' could be 'n' (common abbreviation for 'and') and 'n' is found in the answer.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?

(Another definition for decampment that I've seen is " Escape".)

I've seen this clue in The Guardian.

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