Queen Elizabeth follows favourite saint (5)
I believe the answer is:
peter
'saint' is the definition.
(St Peter)
'queen elizabeth follows favourite' is the wordplay.
'queen elizabeth' becomes 'ER' (abbreviation for Elizabeth Regina).
'follows' says to put letters next to each other.
'favourite' becomes 'pet' (synonyms).
'er' put after 'pet' is 'PETER'.
(Other definitions for peter that I've seen before include "emperor" , "Disciple" , "Man's name" , "Fellow < safe" , "Leading apostle" .)