Nobody is working in north-east (4)
I believe the answer is:
none
'nobody' is the definition.
(not a single person)
'working in north-east' is the wordplay.
'working' becomes 'on' (on can mean working or activated).
'in' indicates putting letters inside.
'north east' becomes 'ne'.
'on' inserted within 'ne' is 'NONE'.
'is' acts as a link.
(Other definitions for none that I've seen before include "Not a thing or person" , "Not a soul" , "service for monks" , "hour of prayer" , "0?" .)