Ambassador's certificate of qualification produced on time (8)
I believe the answer is:
diplomat
'ambassador's' is the definition.
(I've seen this before)
'certificate of qualification produced on time' is the wordplay.
I cannot quite understand how this works, but
'certificate' could be 'diploma' (academic certificate) and 'diploma' is found in the answer.
'time' could be 't' (abbreviation) and 't' is found within the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for diplomat that I've seen before include "Limp toad (anag.)" , "National representative abroad" , "person with negotiating skills" , "Overseas representative" , "Tactful type" .)