Hold up picnic basket (6)
I believe the answer is:
hamper
I believe this clue is a double definition.
'hold up' is the first definition.
(I've seen this before)
'picnic basket' is the second definition.
(as in a food hamper)
(Other definitions for hamper that I've seen before include "Kind of food basket, maybe for picnic" , "Impede the movement" , "Food parcel" , "Food box; impede" , "basket with a cover" .)