One of the supporters in the gallery (3,4)
I believe the answer is:
pit prop
'supporters in the gallery' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'one of the' is the wordplay.
I cannot quite see how this works, but
'one' could be 'o' (I've seen this in other clues) and 'o' is present in the answer.
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for pit prop that I've seen before include "It's a bit of wood in mine" , "Support in mine" , "Roof support" , "supporter of mine" .)