Perform Queen favourite drowned by chatter (10)
I believe the answer is:
perpetrate
'perform' is the definition.
(I've seen this before)
'queen favourite drowned by chatter' is the wordplay.
'queen' becomes 'ER' (short for Elizabeth Regina ie Queen Elizabeth).
'favourite' becomes 'pet' (synonyms).
'drowned by' indicates putting letters inside (I've seen this in other clues).
'chatter' becomes 'prate' (synonyms).
'er'+'pet'='erpet'
'erpet' put inside 'prate' is 'PERPETRATE'.
(Other definitions for perpetrate that I've seen before include "Act" , "Commit (crime)" , "perform" , "Carry out, commit" , "Be responsible for" .)