Strict, always, in London area (6)
I believe the answer is:
severe
'strict' is the definition.
(I've seen this before)
'always in london area' is the wordplay.
'always' becomes 'ever' (synonyms).
'in' is an insertion indicator.
'london area' becomes 'SE' (abbreviation for South East).
'ever' inserted within 'se' is 'SEVERE'.
(Other definitions for severe that I've seen before include "Harsh and punitive" , "sober" , "Drastic" , "Very plain in style or appearance" , "Strict and unbending" .)