Go on tour, initially behind minister (6)
I believe the answer is:
rabbit
'go on' is the definition.
(talk at length)
'tour initially behind minister' is the wordplay.
'tour initially' becomes 't' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'behind' says to put letters next to each other.
'minister' becomes 'rabbi' (I've seen this before).
't' put after 'rabbi' is 'RABBIT'.
Can you help me to learn more?
(Other definitions for rabbit that I've seen before include "Inferior player" , "Hare-like mammal" , "Talk at length" , "one found in the tail" , "Chatter; poor games-player" .)