In short, possible Banksy work is set up (5)
I believe the answer is:
start
'is set up' is the definition.
(I've seen this before)
'in short possible banksy work' is the wordplay.
I cannot really understand how this works, but
'work' could be 'art' (I've seen this before) and 'art' is found in the answer.
The remaining letters 'st' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for start that I've seen before include "Take the first step" , "Jump suddenly" , "Begin to recoil?" , "Begin - opening move" , "Initiate" .)