General worked in government department (6)
I believe the answer is:
franco
'general' is the definition.
(General Franco of Spain)
'worked in government department' is the wordplay.
'worked' becomes 'ran' (eg a machine that works is running).
'in' means one lot of letters goes inside another.
'government department' becomes 'FCO' (Foreign and Commonwealth Office).
'ran' going within 'fco' is 'FRANCO'.
(Other definitions for franco that I've seen before include "Last dictator of Spain" , "Former Spanish leader" , "General . . . . . . was Spain's last dictator" , "Former Spanish dictator" , "was head of state" .)