Urban area to west — and London’s east end (4)
I believe the answer is:
town
'urban area' is the definition.
(town is a kind of urban area)
'to west and london's east end' is the wordplay.
'west' becomes 'w' (synonyms).
'and' means one lot of letters go next to another.
'east end' says to take the final letters (the letter on the right or east end of the word).
The last letter of 'london' is 'n'.
'to'+'w'+'n'='TOWN'
(Other definitions for town that I've seen before include "Community group" , "Urban area larger than a village" , "Nelson, for example" , "Person employed to make public announcements" , "Tinsel- is sometimes applied to Hollywood" .)