The Northern cream's gathered – its inhabitants would say! (10)
I believe the answer is:
manchester
'its inhabitants would say' is the definition.
I can't tell whether this definition defines the answer.
'the northern cream's gathered' is the wordplay.
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'gathered' indicates an anagram.
'the'+'n'+'creams'='thencreams'
'thencreams' is an anagram of 'MANCHESTER'.
Can you help me to learn more?
(Other definitions for manchester that I've seen before include "City of the Halle Orch." , "Synthetic cream (anag)" , "English city" , "It was once snarled up with cars" , "See 22" .)