One turning back from minister and queen twice embracing son (8)
I believe the answer is:
reverser
'one turning back' is the definition.
(a person reversing)
'queen twice embracing son' is the wordplay.
'queen twice' means two substitutions for 'queen'.
'queen' becomes 'r' (r is abbreviation regina. e.g. in ER ).
'queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'embracing' means one lot of letters goes inside another.
'son' becomes 'verse' (I can't justify this - if you can you should believe this answer much more).
'er' enclosing 'verse' is 'everser'.
'r'+'everser'='REVERSER'
'from minister and' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
(Other definitions for reverser that I've seen before include "One who backs" , "He's backing" .)