Army reigns disastrously in foreign city (8)
I believe the answer is:
tangiers
'foreign city' is the definition.
(city in Morocco)
'army reigns disastrously' is the wordplay.
'army' becomes 'ta' (abbreviation for Territorial Army).
'disastrously' is an anagram indicator (I've seen this in other clues).
'reigns' anagrammed gives 'ngiers'.
'ta'+'ngiers'='TANGIERS'
'in' is the link.
(Other definitions for tangiers that I've seen before include "North African port" , "Moroccan port (variant)" , "Moroccan city" .)