Lead for one encountered above call centre (5)
I believe the answer is:
metal
'lead for one' is the definition.
(lead is a metal)
'encountered above call centre' is the wordplay.
'encountered' becomes 'met' ('meet' can be a synonym of 'encounter').
'above' is a charade indicator (letters next to each other).
'centre' says to take the centre.
The central letters of 'call' are 'al'.
'met'+'al'='METAL'
(Other definitions for metal that I've seen before include "Gold or silver in heraldry" , "Headbanger's music genre" , "lead as one" , "Gambling token" , "Zirconium, for example" .)