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' indicates putting letters inside.
'dire' indicates an anagram.
'a'+'st'='ast'
'need' anagrammed gives 'eend'.
'ast' placed inside 'eend' is 'EAST END'.
'in' is the 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" .)