Bag clasp (5)

I believe the answer is:

catch

I believe this is a double definition.

'bag' is the first definition.
('catch' can be a synonym of 'bag')

'clasp' is the second definition.
(thesaurus)

(Other definitions for catch that I've seen before include "Grab hold of - fastener" , "Arrest" , "Something trapped" , "a sort of 22" , "Capture; hidden problem" .)

I've seen this clue in the Evening Standard.

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