Boris possibly admitting Tory leader left city (7)
I believe the answer is:
bristol
'city' is the definition.
(Bristol is an example)
'boris possibly admitting tory leader left' is the wordplay.
'possibly' indicates anagramming the letters.
'admitting' is an insertion indicator.
'tory leader' becomes 't' (I've seen this in other clues).
'left' becomes 'l' (common abbreviation**).
'boris' anagrammed gives 'briso'.
'briso' placed around 't' is 'bristo'.
'bristo'+'l'='BRISTOL'
(Other definitions for bristol that I've seen before include "Brief stay" , "'Bolt, sir, to the port in southwest England (7)'" , "English city" , "West country port" , "West of England city" .)