Many Londoners have material (5)
I believe the answer is:
nylon
'material' is the definition.
(I know that nylon is a type of material)
'many londoners have' is the wordplay.
'have' indicates the answer is hidden within the clue.
'NYLON' can be found hidden inside 'many londoners'.
(Other definitions for nylon that I've seen before include "may be damaged by running" , "Synthetic material used in textiles" , "where ladder can appear?" , "Plastic used for stockings" , "Hose" .)