In Scotland, nothing but prohibition (4)
I believe the answer is:
oban
'in scotland' is the definition.
The definition suggests a singular noun which matches the answer.
'nothing but prohibition' is the wordplay.
I cannot really understand how this works, but
'nothing' could be 'o' (O resembles 0) and 'o' is found within the answer.
'prohibition' could be 'ban' (synonyms) and 'ban' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for oban that I've seen before include "Port and holiday centre on the west coast of Scotland" , "small Scottish port" , "Argyll and Bute resort" , "Northern port" , "Argyll seaport" .)