The most common and most likely answer to this crossword clue is the 3 plus 3 plus 7 letter word GUY THE GORILLA
I've seen this crossword clue in Financial Times
G
U
Y
T
H
E
G
O
R
I
L
L
A
Buddy explains!
The straight part
We know that "Ian Botham" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ian botham = guy the gorilla.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.