Harsh, always, in London area (6)
I believe the answer is:
severe
'harsh' is the definition.
(I've seen this in another clue)
'always in london area' is the wordplay.
'always' becomes 'ever' (synonyms).
'in' indicates putting letters inside.
'london area' becomes 'SE' (abbreviation for South East).
'ever' inserted within 'se' is 'SEVERE'.
(Other definitions for severe that I've seen before include "Grave" , "Strait-laced" , "Taxing" , "Stern, austere" , "Arduous - dangerous" .)