Entrance by the Queen, backed by ship’s siren (11)
I believe the answer is:
enchantress
'siren' is the definition.
(I know that siren can be written as enchantress)
'entrance by the queen backed by ship's' is the wordplay.
I cannot quite see how this works, but
'entrance' could be 'enchant' (to entrance is to enchant or bewitch) and 'enchant' is located in the answer.
'queen' could be 'r' (abbreviation for regina, e.g. in ER ) and 'r' is found in the answer.
'ship' could be 'ss' (prefix in ship names eg SS Great Britain) and 'ss' is found in the answer.
A single letter 'e' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for enchantress that I've seen before include "Bewitching female" , "Siren" , "Seducer" , "Female magician" , "Circe, for example" .)