Material many Londoners will acquire (5)
I believe the answer is:
nylon
'material' is the definition.
(I know that nylon is a type of material)
'many londoners will acquire' is the wordplay.
'will acquire' indicates a hidden word (the answer has been acquired or absorbed).
'NYLON' is hidden within 'many londoners'.
(Other definitions for nylon that I've seen before include "Cover for leg" , "Artific ial (stocking) material" , "Tough synthetic material" , "Artificial fibre" , "The first synthetic fibre" .)