Author O Henry turned up minutes before the Queen (5)
I believe the answer is:
homer
'author' is the definition.
(Homer is an example)
'o henry turned up minutes before the queen' is the wordplay.
'henry' becomes 'h' (symbol for the unit of electrical inductance).
'turned up' is a reversal indicator.
'minutes' becomes 'm'.
'before' is a charade indicator (letters next to each other).
'the queen' becomes 'er' (Elizabeth Regina).
'o'+'h'='oh'
'oh' reversed gives 'ho'.
'ho'+'m'+'er'='HOMER'
(Other definitions for homer that I've seen before include "Weak official" , "Blind man" , "Trained pigeon" , "Type of pigeon" , "Great Greek who wrote The Iliad" .)