The most common and most likely answer to this crossword clue is the 14 letter word SACKVILLE-WEST
I've seen this crossword clue in The Times
S
A
C
K
V
I
L
L
E
-
W
E
S
T
More clues leading to the result SACKVILLE-WEST
Buddy explains!
The straight part
We know that "Writer" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case writer = sackville-west.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.