A procession of empty protest (6,5)

I believe the answer is:

hunger march

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'a procession' is the definition.
(I know that hunger march is a type of march)

'empty protest' is the wordplay.
'empty' becomes 'hunger' (I can't justify this - if you can you should give a lot more credence to this answer).
'protest' becomes 'march' (marching is a kind of protesting).
'hunger'+'march'='HUNGER MARCH'

'of' is the link.

Can you help me to learn more?

(Other definitions for hunger march that I've seen before include "movement that brings protest" , "1936 Jarrow demonstration" .)

I've seen this clue in The Globe and Mail.

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