The most common and most likely answer to this crossword clue is the 4 plus 8 letter word JOHN HUMPHRYS
I've seen this crossword clue in Independent
J
O
H
N
H
U
M
P
H
R
Y
S
Buddy explains!
The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.