Upset the fruit barrel (3)
I believe the answer is:
tun
'barrel' is the definition.
(I know that tun is a type of barrel)
'upset the fruit' is the wordplay.
I cannot quite see how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is present in the answer.
The remaining letters 'un' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for tun that I've seen before include "Large cask for liquid" , "'Large cask, for beer perhaps (3)'" , "Quite enough wine" , "beer barrel" , "One can hold wine" .)