The most common and most likely answer to this crossword clue is the 1 plus 3 plus 1 plus 4 plus 3 plus 2 plus 3 letter word I GET A KICK OUT OF YOU
I've seen this crossword clue in The Times
I
G
E
T
A
K
I
C
K
O
U
T
O
F
Y
O
U
Buddy explains!
The straight part
We know that "Porter's admission a second person's given him the boot" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case porter's admission a second person's given him the boot = i get a kick out of you.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.