How it was specified arms should be dispensed with? (4,4)

I believe the answer is:

laid down

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'dispensed with?' is the definition.
Although both the answer and definition are past participle verbs, I can't understand how one could define the other.

I don't understand the rest of the clue.

Can you help me to learn more?

(Other definitions for laid down that I've seen before include "Stipulated - deposited" , "Ordained" , "specified" , "Insisted upon - abandoned" .)

I've seen this clue in the Evening Standard.

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