The most common and most likely answer to this crossword clue is the 3 plus 7 letter word PEN PUSHERS
I've seen this crossword clue in The Guardian
P
E
N
P
U
S
H
E
R
S
Buddy explains!

The straight part
We know that "clerical people" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case clerical people = pen pushers.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.
What does PEN PUSHERS mean?
PEN PUSHERS noun- A person who performs routine office work, involving mainly paperwork.