A street in dire need in part of London (4,3)
I believe the answer is:
east end
'part of london' is the definition.
(I've seen this before)
'a street in dire need' is the wordplay.
'street' becomes 'st' (abbreviation).
'in' means one lot of letters goes inside another.
'dire' is an anagram indicator.
'a'+'st'='ast'
'need' anagrammed gives 'eend'.
'ast' going into 'eend' is 'EAST END'.
'in' acts as a link.
(Other definitions for east end that I've seen before include "Side of London associated with Cockneys (4.3)" , "part of the capital" , "London region associated with Cockneys" , "London Cockney area" , "ockney London" .)