Leave on London street (6)
I believe the answer is:
strand
This clue is a double definition.
'leave' is the first definition.
(I know this)
'london street' is the second definition.
(I've seen this before)
'on' acts as a link.
(Other definitions for strand that I've seen before include "Drive (ship) aground" , "Beach; London road" , "Maroon - bit of hair" , "Drive aground on shore" , "that may be found by the sea" .)