Many Londoners have material (5)
I believe the answer is:
nylon
'material' is the definition.
(nylon is a kind of material)
'many londoners have' is the wordplay.
'have' says the answer is hidden in the clue.
'NYLON' is hidden within '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" .)