Slip in some London lane? (9)
I believe the answer is:
petticoat
I believe this is a double definition.
'slip' is the first definition.
(I've seen this before)
'some london lane?' is the second definition.
(I've seen this before)
'in' is the link.
(Other definitions for petticoat that I've seen before include "London Lane" , "Woman's underskirt" , "Woman's undergarment" , "Female undergarment" , "Slip" .)